As a bonus, they can leak the coolant into one of the intake ports, causing hydraulic lock. Note that Ford 4.2l V6s in the trucks suffer this same problem, and they do not use Dex-Cool. (And follow the torque spec/sequence religiously!)

There are updated gaskets available that use metal backing instead of plastic, they aren't cheap but they don't fail every 30k miles either. The plastic just sort of biodegrades and the rubber shifts around and it leaks. Pretty much ALL 3100/3400 with the 'flat' intake manifold (not angled like the original 2.8/3.1 FWD port FI setup) have the plastic composite lower manifold gaskets that WILL fail with regularity. If by 'bad batch' you mean 'every single one of them' then yes. This is not normally a problem, but GM had a bad batch of intake manifold gaskets on one of their common V6s that allowed air into the cooling system, which caused the Dexcool to turn into pudding and made many owners quite unhappy with it. Second, it is apparently fairly volatile and does not like being used in a non-sealed system. Late in March 2008, GM agreed to compensate complainants in the remaining 49 states. The first of these to reach a decision was in Missouri where a settlement was announced early in December, 2007. Class action lawsuits were registered in several states, and in Canada, to address some of these claims. It is casually linked with intake manifold gasket failures in GM's 3.1L and 3.4L and with other failures in 4.3L engines. (see last link)ĭEX-COOL specifically has caused controversy. Its known to be crap, even GM and Texaco are admitting it. I could go on, but I'd just be listing a different class action suit for each state, and then regurgitating a million different forum posts. Behind the scenes people are suing the crap out of GM and GM is subsequently suing the crap out of Texaco. On the outside they are saying what wonderful stuff it is while dropping billions on warranty repairs. GM signed a very long contract with Dexcool. It uses any opportunity (especially around leaks or if excess air is in the system) to drop silicates out of suspension, turn to orange jello, eat water pump packing and bearings, and otherwise become acidic without warning. A decade-long study of GM owners, warranty data, and speaking with a few folks who work for GM, Dexcool is just terribly unstable stuff. As far as I'm concerned, Dexcool is satan spawn.

Dexcool coolant gm