I had a thread titled Termostat issue over the last week or so as my car was in the shop for overheating. Turns out they had to flush the radiator. Then a recent reply in the thread mentioned something anout a class action lawsuit against GM about Dexcool causing all kinds of problems.

http://www.consumeraffairs.com/autom...m_dexcool.html

I'm sure there will be folks out there that have not had any problems with Dexcool. But I'm curious if there are any of you that have switched to something else and had no problems. After reading some of the lawsuit reports, GM says you shouldn't replace with a different coolant other than Dexcool because it will cause leaks, etc. (of course they are going to say that or they would basically be admitting they're at fault). Nonetheless, anyone have recommendations on alternative coolants that they have not had any problems with?

 

After reading the info he refers to, I'd like to know the answer to this as well.

I don't have my owners manual or service manuals right now, so can't look up the real GM requirement for radiator fluid.
AMSOIL antifreeze is recommended for applications requiring the following specifications:
Automotive and light Duty Service (ASTM D-5216 & ASTM D-2570)
Heavy Duty Service (ASTM D-6211 & TMC RP330)

Anyone know if these meet GM specs for the C5???

 

IMHO, the problem with Dexcool is that it is too sensitive to contaminants. Some people, including me most of the time, even go so far to only mix it with distilled water. If you go to your local $20/15 minute oil change place and they 'top it off' with the regular green stuff then you WILL have problems. It won't take long for the liquid to turn to sludge. Just make sure that nothing other than a 50/50 mixture of Dexcool (or equivalent) and CLEAN water gets into your system as long as you run the Dexcool.

Many people have added water wetter without problems, but that's up to you to decide if you feel that it's needed. Unless you run your car HARD, then it's not needed.

There are also a few on the forum that I've read have completely replaced the Dexcool with the green stuff, and don't have any problems. Just make sure that you have completely drained all of the Dexcool and done several good flushes first, then check and change it a lot more often than the Dexcool requires.

 

evans coolant

 

I haven't had any problem with Dexcool but I have changed it before in an F body car.

 

The reply to Tom's post is from a Cadillac engineer that posts at caddyinfo.com.
Jeff






QUOTE (TomCalliham @ Aug 22 2004, 08:30 PM)
About a year or a year and a half ago, I started a topic on this dex-cool coolant.I explained that the stuff was doing damage to all sorts of different engines, including several GM models. The reply that i got was from someone named bbob. He said that i didnt know what i was talking about and more or less said i should just shut up ,in so many words. Several other replies showed up in my e-mail with basically the same reply. So you gentlemen can now EAT your words.

Thomas Calliham
tcllhm@aol.com

p.s. Any more replies about Dex- Cool to me are welcomed


Tom....I don't remember telling you to "shut up" or anything of the sort. I think we covered the same facts that have been presented above. There are obviously different view points on the coolants depending on the experience you have had with them and it is incorrect to blame DexCool for all problems. Each problem you mentioned needs to be root caused to determine the true cause of the failure and to determine if the coolant had anything to do with it.

The DexCool is not harmful to the system and will not wreck coolant systems. It is running in WAY too many cars perfectly fine (including a LOT of 4.3 V-6 engines) for it to be a disaster. I have personally seen a GREAT deal of testing on the DexCool product before and after it was released from production and it has always performed admirably. There have been engines from livery service run to 250K and 300K with DexCool and the cooling systems, water pumps, coolant jackets, etc....look like brand new. DexCool works fine.

When there are cooling system problems the findings continue to point to lack of cooling system maintenance and lack of keeping the system full as the root cause of the problems that have been experienced with DexCool. There have also been some failures due to installation of un diluted DexCool where the owner thinks that straight coolant is "better" then the required 50/50.

DexCool will not eat the impeller off a water pump.....!!!! Not sure how to do that other than running the system low or clogged and causing severe cavitation in the water pump....or maybe running straight DexCool causing a more acidic mixture and greater viscosity and more cavitation.

The reaction in the 4.3 V-6 engines is a bit different in that the engines have a cast iron block and heads. The DexCool does not provide corrosion protection for the cast iron when the system is low and the head surfact inside the coolant jacket dries out . It rusts, the rust then gets washed into the coolant and eventually it gets bad enough that the rust particulates start to plug the system and/or unseat the seal of the pressure cap causing the system to loose pressure and boil easier.

No coolant is perfect. The silicated coolants are somewhat abrasive and cause premature water pump seal wear in some situations. The silicated coolants also gel with time and lack of activity which leads to plugged heater cores and such. Silicated coolants also deplete with time as the silicates are sacrificed to plate the surfaces so they need to be replaced.

DexCool provides very long life...very long corrosion protection since there are no silicates to plate out and disappear. The DexCool needs to have the system full to completely protect any cast iron in the system and prevent rust from occurring. DexCool is also acidic (by design) so if it is not diluted and installed in a 50/50 mix it can also cause problems...including heater core and radiator damage if the coolant is not diluted correctly.

Over the long haul there are significantly less cooling system problems and engine failures due to lack of cooling system maintenance with DexCool than with the previously used conventional silicated coolants. You have to take into account ALL problems including water pump seals, head gasket failures due to corrosion, etc....

 

I have switched several of my cars from green to Dexcool. Stuff works great. Only issue is don't let it get low. There are several technical articles written by GM and Texaco on this subject presented at symposia, and their basic finding with all these problems was low coolant. I have even gone into my block and radiator with a boroscope and found it to be exceptionally clean. Stick with the proper mix of Dexcool and make sure it stays full, you will be fine.

 

I completely drained my system (Radiator/Heater Core/Engine Block) and replaced the Dexcool with Evans' Waterless Coolant...my temps dropped 30 degrees.