Coolant Pressure, no heat Head Gasket?

[Scott Glewwe]

Go figure, 101,000 miles and my 2002 won't blow heat (and it's only -16 outside). Temp guage goes up to 180 then drops to zero and stays there. Coolant runs out the overflow and low coolant light comes on. Pulled into shop, replaced thermostats and pressure cap then filled / purged system following the factory service manual directions. Still having same problem. Sounds like I have the same blown head gasket / cracked block problems others have described. I am taking it to the dealer tomorrow. I have a couple of questions for the experts. I had the infamous injector problem at 74725 miles. They were replaced under warranty. Can the injector problem cause a hydrolock in a cylinder creating a crack that leaks combustion gasses into the coolant only under very cold temps (my thinking is the additional contraction of the aluminum block at subzero temps opened the crack enough to create a larger problem. ) My truck has lost a little coolant since I took delivery. Brought it in under warranty and they replaced the thermostat housing. Rather than fight with dealer, I have always just added coolant when the low coolant light would come, on once every six months or so. I suppose it is obvious where I am going with this. Both dealers I have talked to told me that the 100,000 mile warranty won't cover the problem. GM apparently is not extending any "goodwill" on the 6.6L motors (so I was told). Do I have a case to argue for warranty coverage or am I basically SOL? I am going to have the dealer check for gasses in the coolant etc. If cracked block what are the options? Is this DIY project I can tackle with a reasonably well equipped shop or am I looking at a junk yard motor, a GM long block, find a quality rebuild, or is my best option a home equity loan to have the dealer do the work?

[Kennedy]

101,000 shouldn't matter a good dealer will get you covered. Sounds like a gasket or a cup seal. Not too catastrophic, and easily (time consuming) fixed

I'd look for another dealer OR if you are at the dealer where purchased contact the General Manager or owner.

I'm sure I could find a dealer to cover it for you...

[Scott Glewwe]

Thanks John. I am bringing it into a third dealer tomorrow. It's a GMC dealership close to the chevy dealer that gave me the "no goodwill" story. The dealership that sold me the truck, Ryan Chevrolet, is across town (an hour and a half drive on a good day) told me they can't (won't?) cover the cooling problem under warranty. Maybe tomorrow will bring better things.

[DmaxMaverick]

Did they say the wouldn't cover the cooling system because it's the cooling system, or because you were over mileage or time?

The cooling system is covered under the engine warranty, which is 100K/5 years. The radiator and hoses aren't covered. The head gaskets and injector cups are most certainly covered. There is a $100 deductible.

BTW....
Only the heads are aluminum. The block is cast iron, and very stout.

[Scott Glewwe]

They claim the only thing covered past 100K are the injectors. Still waiting to hear from GMC dealer. Hopefully they will give me a good diagnosis. Then I plan to call the dealer I purchased it from again with more facts as to what is wrong. Maybe GM will stand behind their product even if it's 1K over the warranty. Especially with a head gasket (or worse a head) breaking at 100K miles. This stuff shouldn't happen on a bone stock truck that has been used to tow under 5000 lbs probably three times.

[Mark Rinker]

Call the Service Manager (Tully) at Saxon Chevrolet in Elk River if you continue to get the run around. His number is 763.441.1922. Tell him Mark Rinker sent you from TDP and be very straightforward about your issue - and get your current mileage documented quick before its 102,000.

Tully and I are working through a 'low coolant' issue on my 2001, following injector and water pump replacement last fall. (No abnormal water temperatures, or overflowing coolant, however.)

We replaced thermostats during the injector service and coolant overflow cap when this started to occur shortly after the two services. The next swap is going to be the low coolant sensor itself. I noticed yesterday that the light was staying lit for hundreds of miles, even when I added more coolant to the top of the tank...

Keep it simple - look for the obvious - don't assume the worst just yet. At worst it sounds like you have a very fixable - and probably warrantied - fix.

[Scott Glewwe]

Thanks Mark,

The GMC tech replaced the thermostats and said "it heats up now". I gotta be a little skeptical here. To have the thermostats go bad, then be replaced by new GM parts and have them be bad seems pretty unlikely. The drive home was warmer but in the twenty minutes it took me to drive home, after warming up to normal temp, I lost heat for about 5 minutes, could smell the coolant. Engine temp didn't drop to zero and stay there, only dropped about 40-50 degrees. That's different from initial problem. The engine did warm up to normal again - but heat was lukewarm at best. I am hoping for the best and chalking the temporary loss of heat up to trapped air that will work itself out. Other posters here have noted similar temporary heat problems after opening the cooling system. The next couple of days should tell the story.

BTW: I noticed that to get the low coolant light to go off, I had to not only fill the surge tank but stop the engine, turn the key to off and open the drivers side door. When I was trying to diagnose this problem I was driving the truck when the low coolant light came on. Leaving the truck running, I pulled over, popped the hood and added coolant. Low coolant message never turned off but tank was full?? A little trial and error and I found my answer. Hope it helps.

[Scott Glewwe]

Took truck back to dealership - no heat again. Not a thermostat problem. I told them (again) that it was probably a blown head gasket and that GM should cover it. They said if it was a head problem they would try taking to GM.

[Scott Glewwe]

Head gaskets are blown!

They are replacing both and are going to cover it under the warranty! Big cudos to Arrow Pontiac/GMC. Another thanks to the guys on this board. My faith in GM has been reaffirmed.

[Mark Rinker]

Good news on the warranty extension!

Now - I have to ask - has there ever been a power adder, boost fooler, any mod that would increase cylinder pressure over stock on this truck?

[taznj63]

Good news on the warranty extension!

Now - I have to ask - has there ever been a power adder, boost fooler, any mod that would increase cylinder pressure over stock on this truck?

See thread number 5...