As many who know me here, I am not against new technology or product improvement. There have been numerous posts about Dexcool and it's benefits over conventional coolant. I have been an advocate of longer life engine coolant for a number of reasons. However in the last few months I have come across an alarming number of intake gasket failures on cars with less than 50K miles, all GM and all using Dexcool engine coolant. it would appear that cars running Dexcool seem to have a propensity for premature intake gasket failures, sometimes as low as 20K miles. This has to be more than coincidence. With bi-metallic engine components there is more of a likelyhood for gasket failure because of chafing from materials with different coefficients of expansion, but GM seems to be way ahead of the pack and they use Dexcool. I think until it is brought to light in one way or another it may be wise to stay away from extended life coolants until the jury is out. 6 GM vehicles from friends and family including my Blazer very early intake failures. There is more to this than meets the eye.

 

I have used Dexcool in my 86 transam for a few years now with no problem. my friend has a 97 mailbu he bought new and has 120k on it now and our 98 mailbu all with dexcool and i guess we have been fortunate.

after i installed a new radiator and water pump when i first bought my bird is when i switched over to it.

 

i've got that stuff in my car now, been in for the last 10000 miles. didn't really notice any difference from water other then the price.. going to swtich back to water and use some kinda anti-corrosive stuff when it come time to change again

 

Think the problem has more to do with GM assembly than the antifreeze. Our new Blazer started leaking into the crankcase at 12,000 miles. Trips to two dealers and the fix was cooling system sealer - sawdust - in the radiator. Seems to me that GM no longer can build a decent car, and won't fix their junk either. Which is why I bought the 88 Camaro for a daily driver. Something I can work on and enjoy driving to boot. Also notice that the only anitfreeze I can find now is the extended life type that is compatible with all types. The Dexcool is probably a good product though.

 

I'm with Tom3 on this, I don't believe it's the coolant. Chemically the new coolants are far superior to the old stuff.

 

I have DC in everything including my sportbikes. 4 GM cars, however there was a post here by a guy who supposedly attended a seminar about this and he stated that DC attacked plastic parts over time. The intake on the Blazer and most late GM vehicles is a low torque type, 11ft/lbs to be exact after the final pass. They let the gasket sort of float around to eliminate chafing from the different metals, aluminum to cast iron. The gaskets seemed OK on my Blazer until I inspected the coolant passage area. It seemed the gasket which is some sort of composite plastic with rubber seals imbedded broke down at only the coolant section. I have talked to many dealer techs and they simply won't use it. By the way, all GM cars come with sealing tablets which is basically Bars Leak in tablet form. It will be interesting to do some more research into this.

 

Going back for almost 20 years, GM has required the use of sealing tablets in cars using aluminum heads. I had an '86 Cadillac that clearly had it posted in the engine bay that anytime the cooling system was drained, sealing tablets needed to be added to the system.

This may have changed at some point though. I don't recall seeing any such label on my current '96 Cadillac.

I do know that Dex-Cool can cause other problems. The biggest one being that it can start leaving an orange/brown sludge in the cooling system. This can cause the system to clog up and wreak havoc.

My Cadillac has a nice layer of brown film all over the recovery tank. There are also countless stories on the Internet describing the "orange goo" caused by Dex-Cool. Any reputable dealership will also tell of the horror stories they've seen. For some people it seems to be okay, while for others it's a mess.

I ran DC for a time in my GTA, but recently switched back to traditional coolant. During the switch I found about a tablespoon's worth of the orange gunk in my recovery tank. I won't put Dex-Cool back in my car ever again and I am considering removing it from my Cadillac.

 

Thanks for the reply. GM in thier TSB's say that use of sealing tablets is not required on routine coolant changes but does suggest them when a chemical flush is done especially when Dexcool problems are encountered. Every time I did a flush and did not use sealer I lost the water pump within a month. I use them every time I service a cooling system in my cars. The problem with Dexcool seems to be when the system leaks or gets low and the water component of the coolant boils off. You are left with that brown mud. The only way to get rid of it is a chemical flush, GM says 2 flushes are required and to use 2 rad caps. DC seems to plug up the cap and not allow the rad to draw coolant from the recovery tank collapsing the rad hose. Happened in my daughters Cavalier. I am finding from my contacts at the dealers that most of the guys simply will not use it. One of my close friends who works at a Chevy dealer drains it out before he takes his new car home. I am considering taking it out of all my vehicles, but I wanted to hear from the field. I have even seen potential class action about this stuff, course the lawyers always salivate about things like this. Like to hear from more dealer guys.

 

I worked at a local garage for a while and we saw the same car twice in one year for the same gasket. There are good reasons for a multiple class action law suits against dexcool. Just head over to google, type in dexcool, and be amazed (link).

It may not be the coolant, but I would say as far away from it as possible just in case.

Consumer Affairs
Class action lawsuit
Lawsuit overview

Also, on that orange sludge. Some of it is rust...

 

Somewhat on this topic...
I bought a Griffin Aluminum Rad and it came with all sorts of paper work highly recommending Dexcool be used with it...????

 

its not the dexcool- im a tech student for GM- its more likely the use of the composite intake manifolds and such. i have done quite a few intake gaskets on impalas- and alot of stuff with the 3.4s in it. i think its more or less the intake design. If it was such a big problem GM would have written up a TSB about it. the engineers such as the ones on TAC at the dealers didnt say anything about dexcool contributing to the short lift. Dexcool is great i use it in all of my car- on the boiling point charts they list dexcool to have a higher boiling point- i think it rocks- just my 2 cents though

 

I disagree. On the 3.1, 3.3?, 3.4, and now 3.5 it was a poor intake design. It is supposed to be fixed now.....We'll see. Ever since Dex-cool became the standard in GM vehicles I've done twice as many cooling system repairs. I'm not complaining though, it's more money in my pocket. When our 3.0 first came out we were doing oil cooler covers to the tune of 2-3 per day. Really low miliage too 5k to 15K miles. The cover holds the cooler itself in a coolant bath in the "V" of the block. There was a bulletin released saying to use a different sealer on the cover as the old sealer isn't compatible. The Dex-cool was eating the old sealer away.

They won't. Try asking when it's off the record.

One day Dex-cool will be great, It already does have some great benifits, but it needs better gaskets, sealers, and other cooling system componets that work with it.

 

i dont know its still up in the air- ive converted to dexcool on all of my cars- one has 100K worth of dexcool driven miles without a problem maybe its that the gaskets and dexcool arent compatable. i just think they would have come up with a fix by now for it- yeah i have seen alot of impalas in lately getting intake gaskets- but as you said eh i dont care its money in my pocket.

 

INteresting reading here: http://biz.yahoo.com/bw/041014/145371_1.html

Looks like GM has dropped the ball on this gasket design after all, but we all know who's going to pay for it. That'd be us.

 

go to the GM teck link and go to the bottom where they have the fix it right the first time write ups- http://service.gm.com/gmtechlink/ima...e.html#story26 i guess some dealers were replacing the assembly but yeah it is just the dexcool combined with certain gaskets.

Century, Regal, Lumina, Impala, Monte Carlo, Grand Prix, Intrigue with 3.8L L36 Engine – Coolant Leak
Replace upper intake manifold gasket only.

i dont know about you guys but ive been doing this on alot of the v6s not just the 3.8

 

Not only does it cause problems with plastic manifolds, it causes problems with the aluminum components as well. Nearly every 3.1 and 3.4 I've worked on had the aluminum eaten away, pitted.

Its not just related to gaskets/manifolds. Heater cores have been clogging up like never before seen with the traditional green coolant, especially so on the s-series vehicles.

Regardless of anyone else's positive experience with this coolant, I believe it ALONE is the source of the problem. You don't see anywhere near the amount of problems with the propylene glycol. Nearly every GM tech or state inspector I've talked to agrees.