Overheating 2003 GTC, 2.7 :confused:

[bwinterstine]

OK, I'm new to Sebrings but I couldn't pass up this car for $1500.00 even though the previous owner was honest and told me about the overheating problem. At first, I thought that a combination of a mostly water coolant mixture and improper bleeding of the system was the cause. I thought it was boiling due to either the air in the system or too much water vs antifreeze. I also replaced the radiator cap just in case it was part of the problem. I replaced the coolant with a 50/50 mixture and bled the system best I could given that the bleeding valve is stuck (a common problem). The car was much better. However, after driving for a while and then parking; it overflowed a few minutes after shutting down the engine. Strong rushes of bubbles and fluid into the overflow container and this overwhelmed the radiator cap. I also checked that the thermostat opened correctly, the radiator fans operated and that the water pump was pumping coolant. I also checked the plastic housing on top of the engine for leaks ... all good. I figured I didn't get all the air out the first time so I got creative and used a wide mouth funnel that fits tightly into the overflow container (so I can raise the level of the coolant above the bleed valve), I raised the passenger side of the car (so any air in the engine would move more easily toward container) and I rigged up a clear hose bleeding line off of the top 3/8 inch hose near the stuck bleeding valve (top of the engine). The air never stopped running out of the top hose and the faster I ran the engine, the more bubbles appeared. I ran the car for an hour and the same amount of air kept running through the clear hose. The bleeding hose dumped into an empty coolant jug under the car and I kept the funnel/reservoir full during the entire hour. After I gave up, I smelled the coolant recover jug (from the bleed line) and it smelled like exhaust. There is NO oil in the water and there is NO coolant in the block...that's the good news. I think I have a very small head gasket leak of combustion gases into one of the coolant ports in a head. The strange part, I don't notice any white smoke and the car doesn't miss when first started. I don't think coolant is getting into any of the cylinders. I know I have to replace the timing chain and I was planning to do the water pump at the same time ... the chain is noisy. The car has 108K but runs well and is in good shape. Looks like I need to pull the heads while I'm at it? Any thoughts?

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[TNtech]

That was a big risk you took. If you have head problems you're going to end up deeper into it than it's worth. My advise would be pass it along to someone else, cheaper if necessary...take the hit...and lesson learned. In the future stay far far away from 2.7L. Some will no doubt disaggree with me on this.

[bwinterstine]

$1500 is not that bad and I needed a winter project. If I pull it apart and don't see any evidence of a bad headgasket then I'll be worried. It runs too good to think its anything more involved and there is not any water in the oil or oil in the water. I think the block is good.

[bwinterstine]

OK ... here's an update I made some progress last night.

Was able to remove all of the spark plugs, #1 was seized and resulted in stripping the aluminum threads. I've attached 3 pictures. All of the plugs, a close up of the back plugs and #1 and a close up of the "normal" front plugs. You'll see the threads from the head on #1 very clearly.

Onto the compression test. I know that I was not able to seat the compression test hose on the number 1 cylinder so I'll have to assume it was leaking some. Otherwise, it appears that either 1 and 2 are possible cylinders leaking compression gases into the cooling system. Also, I believe #3 is higher because some of the penetrating oil probably made it into the cylinder ... I had to soak all three of the back with penetrating oil to remove the plugs. Basically, the back 3 (numbers 1-3) had a "wet" test vs a "dry" compression test.

I suspect my head gasket issue is either between number 1 and 2 or between either of them and the coolant passages.

#1: 120 lbs
#2: 170 lbs
#3: 210 lbs
#4: 190 lbs
#5: 205 lbs
#6: 190 lbs