We first had the cooling system checked and hoses replaced because we mysteriously were losing coolant. When the problem persisted, we took it back to our faithful mechanic. He gave it a diagnostic and found out at some point the intake manifold gasket had failed and was leaking coolant into the engine oil. We are looking at at least $1055 to fix, possibly $4000 if the water has gotten into the bearings or if the head has cracked (engine replacement). We were having the same problems as another complaintant who posted on this site. No heater and the engine getting extremely hot. We had no warning signs for this, no check engine light. No way to tell because the coolant was leaking into the engine, until the water was so low we could tell by looking in the radiator and seeing no visible coolant!! Also, the reserve tank of coolant was not being drawn into the radiator.My mechanic has told me that the manifold pieces are made of two different types of metal which of course expand and contract at different temperatures, causing friction between the metals which cause stress to the gasket, causing it to fail. To top it off, this was an experiment ( using by GM to reduce the weight of the vehicle I am trying to get GM to cover this under a manufacturers defect, but it does not look good. I have to agree with the other complaint, if this does not get covered by GM, I am going to take my business elsewhere.

Update from Oct 15, 2009: We now know that the most likley cause is a ill designed gasket that allowed Dex-Cool to touch unprotected part of gasket. Dex-Cool(OAT) is highly corrosive to silicone and nylon and also to aluminum (what are your manifolds made of???). There was supposed to be a bead of silicone sealant, but un the faulty designs the bead did not cover enogh of the gasket to protect it properly. I think that Dex-Cool needs to be changed to a HOAT, which is like an OAT, but with " added siilcate inhibitors...that protect the silicone polymer from the type of degradation it suffers with pure OAT(DEX)."- www.imcool/articles/antifreeze-coolant/dexcool2007Part3.php. this is an excellent web site for some insight into the DEX problem. I think any thing coorosive to engine components should not be allowed in the engine! DUH!!!!!!

Update from Oct 20, 2009: I have been talking to GM since 10/07/09 about my blown IMG. Every step, they keep telling me that if I do this, or show that, they will fix the problem. Of course that is not true! After leading me around for almost 2 weeks, they tell me the same story they told me in the begining, I have to wait for a mandatory recall (mandatory from the NHTSA!!!) before they will fix the problem. Well I guess it's on to small claims court!! We'll see how that goes! I love GM!!! Thats why next car IS going to be a Honda!!

If your considering buying a GM product, my family WAS always a Chevy family, remember this: I bought a 2001 Chevy Venture van. At 19,000 miles the rotors dissolved to nothing and brakes and rotors had to be replaced. I bought a Toyota at the same time. No repairs needed. At 26,000 miles, my Chevy required new control arm bushings - won't pass inspection - $300. My Toyota, required no additional repairs at 37,000 miles. At 29,000 miles, my Chevy venture van started to leak antifreeze into the engine via the intake manifold. Add another $1,000 to the Chevy torment. My Toyota at 46,000, no problems or repairs required. I called Chevy last night and they denied all responsibility for a defect that seems to have affected thousands of poor GM owners. Today it was annouced that Toyota surpassed GM as the biggest car manufacturer in US. I'm neither surprised nor will I ever shed a tear for American car manufacturers after what GM/Chevy has done to me. I hope they feel as much pain as I do repairing their garbage.

When the vehicle was still under warranty I lost antifreeze while on a trip to Baltimore. Upon returning home I brought it in to the dealer and they could not find the leak, so they dumped some Bars-Leak in the system. A short time later at a quick-lube the kid showed me where it was leaking and that he worked at the same dealer I had brought the vehicle to and he knew they couldn't find the problem as this was there normal mode of operation, "wait until it was off warranty". Not only is the GM vehicles I own JUNK, their dealers are nothing more than crooks!!! I cannot wait until the day I can scrap the GM junk I own and buy Japanese..... I never thought I would think that let alone write it but I am tired of wasting money on this North American junk! I have never had to replace an intake gasket on any other vehicle I have ever owned, nor has my father and he was a licensed mechanic.