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What technically causes waterpumps to fail?

21K views 89 replies 31 participants last post by  sirwm 
#1 ·
OK, we've all been seeing waterpump thread failures recently, however, no on has really answered what is the technical reason that waterpumps fail?
 
#2 ·
OK

Before TS gets in here. I found several sources of information. This one looks the most useful

COMMON WATER PUMP FAILURES & THEIR CAUSES | FlowKooler Water Pumps - Chevy, Dodge, Jeep, Ford, & more

Exerpt here for your consideration:
1. LEAKING FROM THE WEEP HOLE: To understand leaking from a weep hole let's begin with some common questions and answers.
• What is the purpose of a weep hole?
The two holes you see in the water pump casting are called weep holes. The upper weep hole acts as an air vent. It allows air to evacuate the casting system and prevents the build up of humidity around the bearing. Also the vent allows atmospheric pressure into the pump and the seal remains seated.
The lower weep hole exists to allow fluid to collect or drain out of the water pump to protect the bearing integrity. In a horizontal centrifugal pump there is little space between the bearing and the seal so fluid build-up could potentially threaten the bearing. Weep holes permit this coolant to evacuate the system and protect the bearing. Weep holes also allow atmospheric pressure into the pumps and help the seals to remain seated.
• Does a drip from the weep hole mean seal or pump failure?
Perhaps. Seals will drip as the seal lap in but to understand a more prolonged or intermittent “drip” you have to understand a seal’s design. Seals purposefully drip because capillary action draws fluid from the seal face. As the seal drips, it helps wash loose debris out and reduce the heat load. Most drips evaporate or fall on the road and are not noticed.
Naturally, a more pronounced drip indicates a compromised seal and impending bearing failure.
• What causes a seal to prematurely fail?
High Temperatures:
Mechanical seal have spring-loaded assemblies to keep the carbon seals intact and rubber parts that may disintegrate if the engine runs hot or overheats. If a system overheats to the point of boiling out and the system is permitted to run dry, the polished sealing faces can wear and warp. A worn seal face allows fluids to escape and leak out the weep hole. Most pumps will leak catastrophically shortly after a boil-over.
Electrolysis:
Electrolysis may cause filming and/or crystallization on the seal face and cause the seals to permit fluid into the weep chamber. High mileage vehicle tend to have a greater incidence of seal failure due to pH imbalance that compromises the seal face causing fluids to leak out the weep hole.
Corrosive inhibitors are made up of silicates which plate metal surfaces. The degree of plating that actually occurs varies but as it does, the silicate levels deteriorate over time and the coolant becomes more corrosive. As the corrosion inhibitors deteriorate and the pH of the coolant drops to 7 or below, the result is electrolysis and plating. For this reason most mechanics and recommend a flush & fill at 24 months/30,000 miles. Unfortunately, few car owners flush and fill and radiators and water pump seals become compromised.
Additive Gels:
It seems every few months a new chemical additive for the cooling system comes on the market. Seal manufacturers find concentrations of gel from these additives and/or filming deposits build on the seal face or they find carbon rip out on the ring. These all contribute to premature seal failure.
Abrasive particles
If there are abrasive particles present in the cooling fluid can affect the wear resistance of the seal. Sand is the most common.
2. BROKEN WATER PUMP HOUSINGS AND SHAFTS COMMONLY CAUSED BY: Broken shafts are result of excessive vibration & unbalance and principally due to:
• Bent, cracked, or broken fans
• Fan not squarely mounted on the shafts
• Cracked or bent pulleys due to improper handling or installation
• Overtightened belts cause overload on the bearing and impose a powerful bending force on the shaft causing it to deflect substantially from true center rotation resulting in imbalance and early shaft fracture
 
#3 ·
Having read this, I suspect that some of the early failures are due to heat. A bubble of air gets into the system, that results in cavitation of the pump, the lack of coolant flow allows localized overheating, that overheated coolant begins to move again, travels to the pump area and transfers the heat to the seal area . .. failed seal.

If you have the PH checked, you can tell if you are subject to electrolysis. This is basically the test that my GM tech has been running to identify when the fluid needs to be flushed.
 
#6 ·
That is of course always a consideration, but I have to believe that GM provided the mechanical design and the design paramaters. And I would be surprised if the manufacturer built things that are likely to fail like the seal. The seals and many (most?) of the parts making up the pump come from second and third tier suppliers.

Also, since the pump is used in all ecotec motors, I wonder what the failure rate is in other cars with a similar motor. Are Cobalts having similar failure rates? I have not read that they have the same challenges with their cooling systems injesting air for instance.:thumbs:
 
#5 ·
I have to say it's poor design....the undue stress that is put on a direct drive pulley. Has anyone looked at the '02 Vette (I think). They had a direct drive alternator and A/C compressor. Wondering if their failures are as numerous.
 
#7 ·
While I am sympathetic with your statement, I have no evidence other than the current failure rates that its a good design or a bad design. The water pump loading is not a particularly challenging environment, nor are the loads all that high. I guess I would like to understand better what is the basis for your statement.

Maybe the shock loads are higher? But it does not appear that the failures are due to purely mechanical failures but instead the seals are going bad and puking out the coolant in many (most?) of the cases we have seen documented.
 
#8 ·
Hmmm: I just hit the Cobalt Forum and did a quick search. Seems like a lot of familiar territory with over temp/coolant issues. :lol:

But there does seem to be a higher number of PYTs frequenting that particular forum. Perhaps I need to hang out there. :rofl:
 
#13 ·
So after it was brought up about the number of other LNF motors in other models with WP issues, I posted on several other boards. Very FEW in the HHR or Cobalt have had failiures....many of them being over 120k before they had an issue at all. So, what makes the Solstice and Sky so vulnerable to WP failure? Is it the rear wheel drive? hmmmmm.....this is an interesting question. I will do research on the Corvette that had a majority of the accessories driven internally. And repost here in a day or so....
 
#14 ·
If I had to guess I would say its heat. The kappas are more susceptible to overheating.

I would like to see a correlation between over heating and pump failures.
 
#17 ·
In response to GS' comment re: "lowest bidder" - it is incredibly rare that a domestic car maker does anything BUT grant the work to the lowest bidder. It's been a while since I've supplied anything direct to an OEM but a few years back it was common for them to select the lowest price, require annual price reductions, AND have the supplier commit to covering warranty costs. In many cases the supplier will also design the component or system.

The theory is that the supplier knows his business so he's going to design something that is cost effective to build and if he's responsible for the warranty cost, he's not going to produce something that is prone to failure. The problems start when the supplier has to reduce his price every year for 3 to 5 years. That requires greater efficiencies in his process and/or reduced material costs. Remember the Ford/Firestone tire failures? Nobody will admit it, but Firestone left out a wind of wire in order to get their costs down.

I think the thread is headed in the right direction though. There must be an environmental or mechanical reason the Kappa goes through water pumps more than other vehicles. I'd be shocked if the seals and many of the components are not common across many different water pumps and vehicles - possibly even non-GM vehicles.

Shock loads, heat, etc as many of you have brought up would be suspicious. It would be interesting to see a breakdown of GXP versus N/A, auto versus manual, etc.
 
#19 ·
Good points.

In every production program that I have been involved with, there is a lot of discussion about the shape of the manufacturing learning curve. There are a lot of assumptions made on how quickly performing repetitive processes over time will yield lower costs due to efficiencies. Many manufacturers get in trouble by over estimating the cost savings down the line when setting their starting price structure.

Experience curve effects - Wikipedia, the free encyclopedia
 
#18 ·
I agree with Rob. Practically all the Ecotec engines including the 2.2 in my 2004 Cavalier use the same water pump as in the LNF and water pumps aren't an issue there. I suspect it's heat and perhaps cavitation from air in the system that makes the pumps fail prematurely.
 
#20 ·
I am continuing my research. Found this

Gates offers the tool to address the need for a more thorough way to flush radiators, engine blocks and, most importantly, heater cores. Extensive chemical laboratory testing of coolants and their behavior on water pumps showed that improper cooling maintenance adversely impacts the water pump. Cross contamination of coolant and mixing of coolant chemistry can lead to premature and catastrophic water pump failures.
Field testing also showed that conventional flushing methods do not remove enough solid contaminants, which are held in suspension or have fallen out of suspension and remain in the system. These solids damage the water pump seal, the most critical component.

Tests by the American Society for Testing Materials (ASTM) as well as Gates research show that water pump surface material loss does take place in the system and is not limited to the water pump. This material loss is harmful to water pump seals and results in compromised mating seal surfaces. Over time, all metal components in the cooling system can succumb to premature failure.


And


An auto's water pump failure is usually caused by a bearing failure on the pump shaft accompanied by a water leak. The water leak is generally witnessed coming out of the weep hole at the bottom of the pump. There can also be a leak around the gasket located behind the pump. At times, water pumps have be seen to leak at a certain spot on the bearing surface. A water pump definitely does not leak when the engine is shut off, so it must be pressure tested when the engine is running.

Use a radiator pressure tester for this test. Remove the radiator cap when the engine is cold. Fill the radiator as necessary to bring it to the normal level. Pump the pressure tester up to 15 pounds and look closely to the water pump for leaks. If any leaks are present, the pump needs to be replaced. While the pressure tester is pumped up, check for leaks in the radiator, hoses, the top of the engine for intake manifold leaks, the side of the engine for freeze plug leaks and at the heater core.
 
#21 ·
Coolant Chemistry

Plain Water is an excellent coolant (think swimming pool). Naturally occurring, abundantly available and mixes with almost anything. It can be pumped, filtered, heated, cooled, evaporated, condensed and stored. Essential for plant and animal life and the most widely used of all solvents, even though it is a great automotive coolant, it is not without a few draw backs:

First, it has a tendency to freeze at 0C` (32F`). Not considered a desired trait since during freezing, expansion occurs and thick metal castings can be rendered useless. If this does occur, hopefully the freeze plugs allow enough expansion relief.
Second, water will boil at 100C` (212F`). This is definitely not desired. As the water boils, interruption to coolant flow occurs, the steam vapor displaces the liquid capacity, further reducing efficiency.
Third, plain water will allow corrosion to occur on dissimilar metals, and deterioration to accelerate. The best way to insure your self of expensive cooling system repairs is to fill with plain water only!
Ethylene Glycol A colorless syrupy alcohol, HOCH2CH2OH, used as an antifreeze in cooling and heating systems.1 Mixed with water at 50%, it is found in almost all automotive coolants, and is the backbone of (almost) all coolant chemistry. Ethylene Glycol (EG) has very important characteristics that tailor the coolant mix to the automotive application. The current thinking for automotive coolant is to dilute water with enough ethylene glycol and corrosion inhibitors to change the poor characteristics of water, while retaining the good ones. The primary additives are Ethylene Glycol and Di Ethylene Glycol for freeze/boil protection. The corrosion inhibitors used vary widely by manufacture, and by vehicle requirements. The reason for so many different coolants lies in the complexity of the inhibitors used.

The 3 Main Formulations of ethylene glycol coolant exist are: 1) Silicate based also known as green coolant, 2) Organic Acid Technology based commonly called OAT's, which include extended life or Dex-cool, and 3) Hybrid coolants, which is a combination of organic acid technology mixed with a low dose of silicates. Many so-called "universal coolants" are members of the hybrid family.

Green Coolant is almost a thing of the past on newer cars. What's wrong with green coolant? Well, in a word, nothing! Traditional green coolant is mostly ethylene glycol, silicates, and green dye. Newer coolants have basically the same ingredients, but with orange, red, blue, purple or amber coloring, and without the high level of silicates. Why is the trend moving away from green antifreeze? Longer maintenance cycles. These days we want every thing to last longer.

Silicates are a chemical compound containing silicon, oxygen, and one or more metals, e.g., aluminum, barium, beryllium, borate, calcium, iron, magnesium, manganese, molybdate, nitrite, nitrate, phosphate, potassium, sodium, or zirconium. Silicates may be considered chemically as salts of the various silicic acids. 1 In a cooling system, silicates offer metal parts ( especially aluminum ) a high level of fast acting protection against corrosion and pitting that is vital. Silicates "charge up" a cooling system with protection that lasts about 2 years. After two years, the coolant mix needs to be replaced with new coolant and water. New every two.

Silicates offer instant protection to the cooling system. Heavy duty vehicles rely on silicates to give precise amounts of protection, and can be recharged without draining the entire coolant. Silicates do have a life, and it's a short one - two years. If left longer, build up inside the radiator begins, and the silicates actually contribute to cooling system problems. Silicate drop out occurs after the coolant has been "spent", and the inhibitors drop out of solution. Silicates are blamed for deposit build up in radiators and heaters, causing engine overheating and poor heater performance. Once the silicates drop out of solution, dissimilar metal corrosion is no longer suppressed, and metal components begin to deteriorate.

Silicates are deemed to be abrasive in a cooling system, and are blamed for premature water pump seal failure. With the average miles per year per car on the rise, it does seem to be a valid concern. But is it worth the price of a dex-cool clean up? If your water pump is timing belt driven, the water pump may be replaced at 60,000 or 90,000 miles anyway.





Organic Acid Technology or OAT's are coolants that are formulated without the use of silicates. Since silicates have a short life, removing them allows a longer service life. Typically, coolants advertised as 5 year, long life , extended life or Dex-cool are examples of OAT's. Common components to OAT coolants are Carboxylate, sebacate, and 2-ethylhexanoic acid (2-EHA), which are corrosion inhibitors, used instead of silicates. Depending on which manufacturer is filling the jug, the inhibitors may change. Dex-cool uses 2-EHA which among other things is a plasticizer which has the effect of softening plastic. GM intake manifolds are made of plastic........... If it is found that Dex-cool is dissolving the gasket material, it will validate what some folks have been saying for a long time: Dex-cool eats gaskets. We'll see. Prestone doesn't use 2-EHA in it's long life coolant, instead uses carboxylate.

As long as the cooling system is in good shape and the chemistry is balanced, these coolants have demonstrated that in fact they can go longer that their predecessors. However, when the balance is upset, either by improper filling procedures or weak concentrations or improper manufacturing, the OAT can come apart, causing thousands of dollars in repair bills. GM's Dex-cool is a huge problem on some vehicles. Class action suit pending.....

Hybrid Coolants, also known as HOAT's or G-O5 is a OAT coolant with a low silicate charge added. The idea is to reap the benefits of longer life OAT while retaining the positive characteristics of silicates. In areas where hard water deposits have been a problem, the HOAT blend holds up very well. The main inhibitor in popular HOAT's is Benzoate

Most GM cars changed from green coolant to Dex-cool in 1996, while Chrysler went from green to HOAT in 2002. Ford changed to HOAT in 2003. The European vehicles have never been a fan of traditional green, and have been using HOAT or OAT right along. The Asian vehicles switched from HOAT to OAT in 1996. The trend is clear, silicate levels are dropping, and as OAT inhibitors get better, soon silicates may be a thing of the past. Thanks to Zerex, a colorful chart is available to pinpoint coolant types for various vehicles.

Propylene Glycol A colorless viscous hygroscopic liquid, CH3CHOHCH2OH, used in antifreeze solutions, in hydraulic fluids, and as a solvent.1 Although the thermal properties of PG (propylene glycol) are less desirable that EG (ethylene glycol), there is one main advantage- it is not toxic to humans and animals. While EG is sweet to the taste and animals are attracted to it by curiosity and smell. Because of it's taste and toxicity, EG is responsible for many pet deaths per year. PG may be the logical choice if garage space is shared with a pet. Recent formulations of PG include a low silicate OAT with purported 7 year 70000 mile life. We'll see about that.

Waterless Coolants Not enough is know (by me) about waterless coolants to be able to comment on them. However, the idea is this: if we can get rid of the limiting properties of water e.g.: boils at 100C`, freezes at 0C`, allows corrosion, conducts electricity & allows electrolysis to occur, while increasing the thermal absorption of the coolant, ...viola`! We'll see.

Coolant Additives are not coolants themselves, and must be used cautiously. They change the chemistry and properties of the coolants so that desired "behaviors" are achieved. The biggest sought after behavior is the reduction of surface tension. Other goals include pH reagents, electrolysis suppressors, water soluble oils, increased alkalinity reserves, the list goes on and on. While very useful in treating a specific conditions, it is not recommended that a person put one of everything in a cooling system. Not only would the coolant be diluted, but the chemistry might be quite interesting!
 
#22 ·
And GM response to DEXCOOL problems

GM’s Jay Dankovich and Equilon Enterprises’ (Texaco) Stede Granger directed a 2-year study of thousands of DEX-COOL cooled vehicles. Armed with the results, they really didn’t have anything bad to say about the coolant. In fact, they strongly defended the product’s reputation. What they revealed to the audience is that specific models of GM vehicles have specific cooling system contamination problems. And essentially, that DEX-COOL is not the culprit!
Their presentation started with a 14-minute video that is now being circulated to technicians at GM dealers nationwide. In the video, GM’s trainers succinctly described the problems that have been found and the corresponding corrective actions to be taken by technicians.

Here’s a recap of their entire presentation.

1. Keep the cooling system filled. In fact, fill the reservoir bottle to “Hot” level when the system is cold. Problems arise when a system’s coolant level is not maintained. (Fleet vehicles receiving regular maintenance, and with reservoirs kept slightly above normal, do not show signs of contamination. This even applies to the specific “problem” vehicles.)

2. The coolant problems found in this survey were caused by system contamination, and not due to the breakdown of DEX-COOL.

3. Check and keep the pressure cap clean and functioning. A contaminated and/or malfunctioning cap causes low coolant levels, which in turn causes overheating and a greater loss of coolant: the notorious vicious cycle. No matter what the vehicle, if the cooling system acts suspiciously, test the pressure cap.

4. On the ST vehicle models mentioned in the GM DEX-COOL video, you “must” replace all suspect radiator caps, especially those with a Drop-Center design, with a Stant Model 10230 or 11230 (Spring-Center type). (Just do it.)

5. Make sure that the coolant is at a 50-50 mix. Often, the flush water was not being removed from the engine block. Consequently, when a 50-50 mix is added to the system the resultant mixture could approach 30-70. Like any fluid that has been diluted beyond its recommended levels, the lowered level of inhibitors will not be able to protect the coolant system effectively. Low levels of inhibitors can cause pitting on aluminum surfaces and general corrosion of cooling system metals.
. A safe method of achieving a true 50-50 mix is to first determine the actual capacity of the system (use the owner’s manual). Then add 50% of “that” amount of undiluted DEX-COOL (or any coolant), and top it off with water.

7. Mixing a “green” coolant with DEX-COOL reduces the batch’s change interval to 2 years or 30,000 miles, but will otherwise cause no damage to the engine. In order to change back to DEX-COOL however, the cooling system must first be thoroughly drained and flushed.

8. Bacteria cannot live in a hot, Ethylene Glycol environment and is therefore not a threat to DEX-COOL.

9. While there have been intake gasket failures on CK Series, V8 powered vehicles for various reasons, DEX-COOL has never been found as a cause.

10. Use a refractometer to check the condition of DEX-COOL. Its inhibitor package is strong enough that if the batch still provides proper freeze protection, it is probably still providing proper corrosion protection as well.

11. DEX-COOL can handle the minerals in hard water better than silicated conventional chemistry coolants. Drinkable water is suitable for top off.

12. In ST Blazer applications where the radiator cap is mounted at an angle to the ground, the vehicle is more susceptible to radiator cap contamination and its related problems. The Stant 10230 is a wise choice for these vehicles.
Forward - DEX-COOL 2007
 
#23 ·
Another interesting article I found.

Under Pressure: Underhood Service
The Dex-Cool Issue
Mention the word Dex-Cool and some motorists see nothing but red. General Motors has taken a lot of heat about their orange-colored organic acid technology (OAT) long-life coolant clogging radiators. There have been numerous class action law suits against GM over the issue, and a lot of rhetoric and misinformation circulated on the Internet blaming Dex-Cool for a variety of cooling-related issues including radiator clogging, engine damage due to overheating and intake manifold gasket failures.

The latest GM technical service bulletin on this subject (00-06-02-006C) dated May 1, 2006 covers the use of Dex-Cool in all 2007 and earlier GM passenger cars and trucks (including Saturn), 2007 and prior HUMMER vehicles, and 2005-’07 Saab 9-7X.

First and foremost, GM does not approve using any brand of antifreeze that claims to be “Dex-Cool compatible” unless it has been licensed by GM. Approved brands include Dex-Cool coolants made by Chevron, Shell, Prestone, Valvoline, ACDelco and GM Vehicle Care. GM says using a non-approved virgin coolant or recycled coolant may void the cooling system warranty. What’s more, adding non-approved coolants to a vehicle may degrade the integrity of the cooling system making the coolant incapable of lasting five years or 150,000 miles.

In spite of all the controversy over Dex-Cool, GM continues to stand behind their coolant and blames most of the problems that have occurred on cooling system contamination and improper maintenance. GM says the integrity of the coolant is dependent upon the quality of the antifreeze and water. If poor quality water is used with Dex-Cool, it may cause problems. So GM recommends using distilled or de-ionized water with Dex-Cool.

GM also frowns on the use of sealing tablets in the cooling system except in special circumstances. The tablets should not be used as a regular maintenance item after servicing the cooling system. Discoloration of the coolant may occur if too many sealing tablets have been inserted into the cooling system. This can occur if sealing tablets are repeatedly used over the service life of a vehicle.

GM also advises to only use Dex-Cool if a vehicle was originally equipped with Dex-Cool. In other words, don’t switch back to a conventional green coolant or a hybrid OAT coolant that contains silicates.

Mixing conventional green coolant with Dex-Cool will degrade the service life of the coolant from five years/150,000 miles to two years/ 30,000 miles unless the contaminated coolant is removed from the vehicle. GM says the cooling system must be flushed twice immediately after the contamination, and then refilled with a 50/50 mixture of Dex-Cool and clean water to restore the enhanced corrosion protection and extended service life of Dex-Cool.

After five years or 150,000 miles (whichever comes first), the coolant should be changed, preferably using a coolant exchanger. If the vehicle was originally equipped with Dex-Cool and has not had problems with contamination from using non-approved coolants, the service interval will remain the same and should be good for another five years/150,000 miles.
 
#24 ·
and
Orange Sludge
So why does the coolant turn to orange sludge in some vehicles? The problem has been blamed on a combination of factors including low coolant level due to a faulty radiator cap or lack of maintenance, oxygen in the cooling system, using water contaminated with minerals or salts, and adding non-approved coolants to the vehicle. Sludging problems, says GM, have not been caused by Dex-Cool breaking down. The sludge is typically iron oxide produced by rust inside the cooling system.







GM has a training video available titled “Understanding Radiator Cap and Cooling System Contamination,” which is free but you do have to pay a small shipping and handling charge. You can request a copy of the video by calling GM’s technical training fulfillment center at 800-393-4831 and ask for part number 2578000100, or kit number RADAPK.

To avoid sludge problems, the cooling system must be kept full. GM advises filling the reservoir bottle to the HOT level when the system is cold. Keeping air out of the system is the key to preventing problems down the road.

Close attention also needs to be paid to the radiator cap. A cap that does not seal properly or is contaminated with rust or dirt can allow coolant loss and air to enter the system. The cap should be pressure tested and replaced if it fails to hold pressure. The GM training video also recommends the OEM “drop-center” style radiator cap with a Stant Model 10230 or 11230 “spring-center” cap. If contamination forms inside the cooling system, the debris tends to gum up the pressure relief valve in the drop-center style caps, especially on vehicles like Blazer trucks where the radiator cap is mounted at an angle. This may prevent the valve from sealing properly, allowing a loss of pressure in the system, coolant loss and additional air contamination that only accelerates corrosion even more.

Nissan has also issued a radiator cap-related service bulletin for its 1999 and later vehicles. TSB #NTB04-018 says overheating and coolant loss problems can be caused by a radiator cap that does not seal properly. The bulletin advises technicians to inspect the gasket on the underside of the cap to see if the gasket is swollen (enlarged) as this can prevent the cap from sealing properly.

Another company that has noticed radiator cap issues is BMW. They actually issued a recall (#98V178000 in August 1998) covering a radiator cap issue on 1995 5 series BMWs. The OEM radiator cap apparently holds too much pressure, and may cause the heater core to burst if the engine overheats. The fix here was to replace the original cap with one that vents at a lower pressure to reduce the risk of passengers being burned by hot coolant blowing out of a ruptured heater core.

Volkswagen had a similar recall on 49,273 Jetta II models. Recall R1995/089 covers the possible leakage of coolant into the passenger compartment due to a burst heater core. Vehicles affected are VIN 1GLW16006 to 1GMW826935, built August 1989-’91. The fix here was to install a bypass valve in the heater core inlet, a non-return valve to the system, and lining the heater box with absorbent foam. A similar recall was also issued for 200,000 1983-’89 Jettas (recall R1995/013).

Wrong Coolant Mix
In some instances, coolant sludge can occur if the coolant contains way too much antifreeze and not enough water, or there is not enough antifreeze in the coolant and corrosion takes over. The recommended coolant mix is almost always 50/50. But if the radiator is drained and refilled without flushing the system, mixing new coolant with old may result in coolant that is too diluted or over-concentrated. Over-diluted coolant (too much water) may prevent the chemical inhibitors from stopping rust, allowing metal surfaces to corrode. GM recommends using a coolant refractometer rather than a hydrometer to check the strength of the coolant.







Heater Core Failures
GM is not alone when it comes to certain vehicles that have experienced repeat heater core failures. Some of these failures have been blamed on sediment circulating with the coolant causing abrasive wear in the heater core, while other failures have been blamed on electrolysis corrosion. Most of the failures have been with aluminum heater cores, rather than copper/brass cores.

GM tech service bulletin #05-06-02-001 dated Feb. 24, 2005, says aluminum heater core failures in 2005 and earlier cars and light trucks may be due to a variety of causes, including erosion, corrosion or insufficient inhibitor levels in the coolant. Other parts that may also suffer damage include the radiator and water pump. In such instances, the strength and condition of the coolant should be checked prior to installing new parts. If the vehicle’s coolant level is low, has leaked out, or the customer has repeatedly added coolant or water to the system, the cooling system should be completely flushed to remove all possible contaminants.

GM also says to inspect the coolant flow restrictor if the vehicle is equipped with one. Too much coolant flow through the core can cause erosion inside the core.

You also need to check for electrolysis in the cooling system. This test can be performed before or after the system has been repaired using a digital voltmeter set to 12 volts. Attach one test lead to the negative battery post and insert the other test lead into the radiator coolant, making sure the lead does not touch the filler neck or core. A voltage reading over 0.3 volts indicates that stray current is finding its way into the coolant. Electrolysis is often an intermittent condition that occurs when a device or accessory that is mounted to the radiator is energized (such as a poorly grounded electric cooling fan). Broken, missing, loose or corroded ground straps between the engine and chassis may also force electrical currents to flow through the coolant as a ground path.
 
#25 ·
Wow this thread got allot of information thrown at us.I used to be a manager in a sheet metal production shop that also made parts for GM.I know as a fact that GM is constantly pushing their vendors to make things more cost effective like for instance automation and stock control.They want the best product with the stringiest quality control they can possibly get.I have seen their quality specs and controls so I know they really want the best.The issue here is that in some cases,mind you some and not all ,metal suppliers sell their metal to who ever pays more,an example the company was at the time making the back panel for the Cadillac that fits in the trunk and holds some relays or whatever.The company had a very hard time buying the metal for stamp production because China was paying premium prices for metal.Not all metal is produced the same so manufactures had to purchase what they could to get the product out,which means that quality get affected but production goes on.I seen battery trays,trunk parts,fuel rails and many other parts produced in this same factory.Business is tough to say the least.

Now all that being said,lets look at the car manufactures,they need to stay in business .Part of that is when they produce a product like any other company they know the life expectancy of that product(business 101).Do you think GM would be in business if they made a product that works or never fails?If a radiator last x amount of years well that just makes more return business for the manufacture and mechanics.

I know I spouted off a little here and I will soon have my head handed to me also , but it all makes good business sense for them and like anything else the consumer ultimately pays out the wazoo.
 
#26 ·
With everything posted....im gonna simplify my earlier post about poor design. The waterpump sits under the turbo and right infront of the catalytic converter. All of this heat dries out the seals and is extremely hard on the bearings. There is NO airflow in this spot either. Thus the reason GM moved the turbo and converter to the other side of the motor for the Regal, but more important the rwd ATS.
 
#27 ·
Ghost, I really think you are on to something here.

The heat is shortening the life of the water pumps, and if you combine that with any other factor, from low coolant, to contamination, or air trapped in the system that inhibits flow to the pump impeller then you have a very bad environment for your water pump.:agree:
 
#28 ·
Wow, good info to digest (and not sure I understand it all).

According to the Evan waterless vid water boils at 212 degrees, Evans waterless 375 degrees, plus doesn't have the same corrosive properties associated w/normal antifreeze's (plus is lifetime of vehicle). However, the website also seems to indicate going from antifreeze to waterless is a "conversion". Which means to me first you have to find an Evans dealer and than find a shop to perform the conversion? I did email them and ask it that assumption is correct.

BTW, here a PDF link from Evan waterless coolant website regarding how Evans waterless coolant was tested and seals: http://www.evanscooling.com/assets/Uploads/Evans-Coolant-1000-hr.pdf
 
#29 · (Edited)
Um....maybe if DDM Works is listening, they can design a heat sheild for the waterpump!! I would DEFINTELY buy one!!!!

EDIT:

Watch yourselves with waterless coolant. I just spoke to a former tech who has had experience with waterless coolant. He said that waterless coolant runs the motor WAY hotter. Like also stated here, the other con against it is that you can't just add water when you're low. The other thing was with the higher boiling point, the pressure doesn't build up like a water based system does. I will talk to an engineer for GM this weekend and see what his recommendations are on this.
 
#30 ·
Excellent, Rob. Thanks! Know more now than I ever did. Especially since I also own one of the Slanted cap vehicles. I wonder if plastic intake-equipped vehicles want their engine running as hot as a waterless coolant could allow.
 
#31 ·
The chemistry involved says that as long as the PH is "neutral" that is around a value of 7, it is not corrosive.

Effect of pH on General Corrosion Rate
The effect on Corrosion of the pH of water to which iron or steel is exposed is influenced in the following manner.
The potential of hydrogen or symbol (pH) is defined as the negative logarithm of the hydrogen concentration, represented as [H+] in moles/liter.
pH = -log [H+]
The pH value is used to represent the acidity of a solution
In chemistry, pH is a measure of the activity of the (solvated) hydrogen ion. p[H], which measures the hydrogen ion concentration, is closely related to, and is often written as, pH.[1] Pure water has a pH very close to 7 at 25 °C. Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline.


For corrosion to occur, the Ph value of the coolant needs to be greater than or less than 7. If you test it and its at 7, corrosion is not ongoing.
 
#32 ·
Here's the response from Evans waterless coolant:

The conversion does not have to be done by an Evans conversion center. If you have mechanical ability, or have a garage that you normally work with that would be inclined learn the product, a conversion can be done there. The best way to do a conversion will depend on the vehicle you will be converting, and we would be more than happy to walk you or your mechanic through.
In short; the entire cooling system needs to be drain and flushed either with the Evans Prep Fluid or clean water. Depending on what type of anti-freeze/water mixture you have in the vehicle at the moment there may be another step of having to run a chemical flush through the system. Then you would be able to fill with the Evans coolant.
At the moment we do not have any converting dealer in MI at all. As mentioned, if you have a garage you work with or would want to convert it yourself, we have a large distributor in IL that can ship you the coolant quickly and at a cost effective rate.
Thank you for your inquiry! Please let us know if you have other questions,

Evans Technical Support
888-990-COOL

I should email them and ask about concerns regarding higher engine heat because that is a good point. However, the DIC does reveal engine temps.
 
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