rubyred93

Can someone please set this straight for me? Both the Chilton's Manual and several friends strongly advise against the use of DexCool in a '93 - something about it being detrimental to the alum. heads. Yet others on a different Corvette discussion forum claim it is perfectly safe.

I thought DexCool was a late '95 introduction and isn't supposed to be used in a '93. Does anyone know for sure?

PeteL

GM does not recommend using DexCool in pre 94 vehicles. Here is the TSB from GM on the subject - look down to "back service".

http://www.geocities.com/crackeregg/00-06-02-006.html

I use the green stuff and change / flush every two years. I use distilled water for the final flush and fill.

Good Luck with your choice.

Pete

vettenuts

In the end, the choice is really yours to make. Having stated that up front, I researched the information available on DexCool for two years and then decided to switch my cars over (four in all). I will say there is a lot of mis-information on the product including wive's tales that are beyond belief. Check the Texaco website for product information. Check www.imcool.com for information on cooling problems with GM products and Dexcool (note, the problems were not related to the Dexcool) and look into other technical resources. That is the only way to get factual information from which you can decide to switch or keep the green stuff. I am hesitant to make a recommendation on this one, but the aluminum head story is BS. Dexcool was developed for extended drain capability in multi-alloy cooling systems, with aluminum being one of the primary metals. I also did an inspection of my motor and radiator last winter with an articulated boroscope. All was exceptionally clean with no evidence of problems from using Dexcool. I did this to further convince myself that all I was reading on the message boards was mis-information.

Carroll B

I've had it in my 93 for 3 years now. I like the fact that it is not supposed to contain the silicates that the regular stuff has. The silicates are supposed to be hard on the water pump seals.

rubyred93

All three of the above responses are very interesting. I did recently do a complete cooling system flush and had gone with the "green stuff" as I was cautioned against DexCool. I find it very interesting that some owners are using the DexCool without incident.

Does anyone think that the water pump seals were different in composition for '93, and then changed in some way for model years after that?

Thanks for the replies - you guys are always on the ball.

PeteL

There was a posting on the general c-4 board a few months back, can't remember the person who posted - but they were with Dana corp and said they participated in a study of seals / gaskets for use with DexCool and cautioned against using the product with older seals / gaskets. This is the only time I have heard this mentioned and wonder if this is why GM does not recommend DexCool for older engines.

I have a 99 Suburban that came from the factory with DexCool. It went cloudy, and I had the dealer check it. The pH had gone low (below 7.2) and the dealer recommended a flush. Same exact thing happened to a friend also with a 99 Suburban and he had to flush.

Another story on the Suburban board. 96 Sub with little over 100K miles had intake manifold gasket failure. Shortly thereafter began overheating and found radiator 80% plugged. The coolant had reached the end of it's useful life and had performed well to that point. However the end result was an expensive repair, and lucky it was caught in time before engine overheating.

For interesting reading on DexCool go to the Impalla SS boards or blazer boards, these vehicles seem to have more than their fair share of problems with DexCool gelling. Why?

My personal opinion is that there is something that causes the stuff to "turn", probably air in the system or perhaps hot spots or cavitation. Whatever it is, Texaco / GM is not forthcomming with the reasons that it seems to go bad quickly with the insueing gelling and corrosion in some cases.

There is something going on but don't know what it is. The big trucks use a very similar mixture to DexCool and can get 500,000 miles out of the stuff with proper additives and testing. Not sure why the consumer version of long life coolant is having problems.

My limited personal experience leads me to treat it as a two year coolant. If I had any loss of coolant during that period I would flush it. The radiator on my 99 Sub is also clean as a wistle, but I'm not sure what would have happened if it were not flushed at two years. I check pH at least twice a year, but hate letting air into the system to do so.

I think DexCool has positive attributes, but for me it's not coolant life. Unless and until GM / Texaco can explain WHY the failures happen and how to propery prevent sudden failure I will stay with the Green in cars that came with it and Orange in those that came with it. I also wonder if once the system had the green, if changed to DexCool will there be any improvement on pump seal life?

Finally, with all the leaks and the heat that these cars develop, are we putting DexCool in just the position that it requires to fail? We know the green stuff fairly well and know that it requires flushing every two years. I have enough questions about DexCool to not take a chance at this point.

Sorry for the $2 worth!

Pete

rubyred93

Thanks Pete -

Always appreciate honest and open information. This seems to be an area for debate, I guess. And I don't mind the $2 worth at all, I like to be exposed to as much information as possible, it's a great way to learn about these cars and all of their idiosyncrasies. I appreciate your response. Very interesting.

y5e06

well, I use dexcool now. I used to do a stupid thing. I ran straight water for a year. I'd flush it every two weeks. It ran cooler when I was racing. but, as you can guess my water pump seal went south. When I replaced it I did a complete and thorough flush and went to dexcool. The container said it was safe for all cooling systems. So far no problems. been about a year now. I plan on changning at two years anyway. The car seems to run about 5 degrees warmer with dexcool than the green stuff. but that could also be due to the replacement of the temperature sensor, slight variation in calibration. dunno.

2dogs

OK stupid question time - what brand is the 'green stuff?'

Where can you get DexCool and GreenStuff - don't remeber seeing it.....

2dogs

Hmmm, is the greenstuff prestone....?

GlobalGreg

Yes

vettenuts

The best deal I have seen on any of them is at Wal Mart, including Dexcool.

2dogs

So 50/50 of my choice? We need to run a poll....

Thanks for entertaining my questions also.

vettenuts

Any chance of finding this thread, I missed it.

skeet

I have been using DexCool for about 6 years in my 85 and 1 year in my 88. The inside of the radiators is bright and shiny with zero signs of corrosion. I also change it every 2 years and use a 50/50 mix with distilled water.So what is the problem?

PeteL

Bob, darn it - I replyed to the thread asking for more info. Then had to go on a business trip, when I got back I could not find the thread.

There is a very remote possibility that I copied it to my hard drive, I'll try and find it. Don't think I did as the thread was still active - then dissappeared.

splochocki

what do you guys think about quick lubes doing a flush and fill with your coolant

rubyred93

Personally, unless it is absolutley, posivtively necessary, I do not allow others to work on my car. Too many times I have seen disrespect for other's cars in the type of environment that you speak of. If you can do the work yourself, you can then be certain of what was done and the quality of the workmanship.

vettenuts

I try not to let anyone touch mine either, I figure I can screw it up pretty good myself Seriously, most of those places hire kids that are not familiar with the cars and the requirements. Serious problems can develop if they screw it up, just ask anyone who had to replace an opti-spark unit. I think you are better off spending the money on the GM service manual and the tools and doing it yourself.

DON M

I work with commercial A/C equipment and we use drycoolers to move heat around. The fluid in a drycooler is anti-freeze. In older systems we use Ethylene Glycol which is the ingredient in the green stuff. In some areas we have to use Propylene Glycol (Dexcool)due to environmental concerns. The Propylene Glycol is not as efficient as the Ethylene Glycol in removing heat (less btu/lb), and more expensive. As we all know the Ethylene Glycol will kill dogs and cats and the Propylene Glycol is an ingredient in soft drinks and some cheap wines. They are similar in their reactivity to the system metals and require the same maintenance.
Personally I use the cheap stuff and dispose of it properly.
Don