Lower Intake manifold gasket replacement

[slentz71]

Has anyone had the joy of changing the intake manifold gaskets on the aztek. We were having an overheating problem, thought it was the thermostat and changed that. Problem came back. I have the upper and lower manifolds off now, but the old gasket does not look bad and I have fears that it is the head gasket. No coolant in the oil, but we were burning a bit of coolant when the overheating problems surfaced. The lower manifold bolts took no effort to remove, an easy turn with the ratchet and then I could practically turn them by hand. Do you think this was the problem and a new gasket and proper torque on the bolts will fix it, or should I look at the head gaskets too? ( I really do not want to tear this engine down any farther)

2001 Aztek 3.4l engine

[Airjer_]

the 3.4 had a lot more issues with head gaskets especially in the minivans and suv's. If you didn't see any external leaks and there was no milky oil than I would put money on the head gaskets.

Pull the plugs and see if any of them are cleaner than the others.

Also are you sure the cooling system was operating properly. Fans coming on, plenty of flow, no debris built up on the outside of the radiator?

[wafrederick]

It could be a bad thermostat too,stuck closed.When getting the new intake gaskets,get the Dorman kit which comes with new intake bolts and GM says to replace the intake bolts.Dorman's kit comes with every gasket and O rings needed.The Dorman kit is cheaper than Fel Pro's kit and Fel Pro's kit does not come with new intake bolts.

[Airjer_]

I think the only difference between the old bolts and the new bolts is the threadlocker/loctite on the new bolts.

[slentz71]

Finished disassembly this afternoon. When I actually removed the intake gasket, I noticed it had deteriorated on the back side. I also have one intake valve and passageway that is very clean and the plug in that cylinder was clean. I think coolant was getting sucked into that cylinder and being burned. (I hope) I can't see that one valve being clean and the others being dirty without something running through there. Gonna take a shot and just change the manifold gaskets and torque them like they are supposed to be. There hasn't been any loss of power and nothing to indicate exhaust or oil getting pushed into the coolant, so here goes nothing.

[Airjer_]

Originally Posted by slentz71

I also have one intake valve and passageway that is very clean and the plug in that cylinder was clean. I think coolant was getting sucked into that cylinder and being burned.

Cylinders 1, 5, 2, and 6 are possible for this to happen.

[slentz71]

Got the gasket changed and the smoking and rough idle went away. Coolant temp gets too high about every 4 or 5 times we drive the vehicle. I didn't flush the cooling system like I should have and I only drained it from the radiator drain, so I am hoping a good system flush will fix the overheating. Acts like it is getting clogged from time to time.

[slentz71]

Had the system flushed and filled at a mechanic. Temps were consistent and good heat for the day. Car sat for a day and when I drove it today, no heat and temp was running toward the higher end of the range. It would actually get cooler when I revved the engine up, so I'm wondering if it could be a bad water pump or another problem.