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Overheating issues, lower intake manifold?

J

Junixx

New member
Ok folks this problem has been plaguing me since this past spring.

My cars' temperature likes to fluctuate very badly. The gauge will tend to creep up (sometimes to the red line) and while this is happening the heater will stop working, after a little bit it will drop back down to normal temps and the heater will start working again. I have bled it and bled and it when I bleed it seems to work fine for a little while, then it comes right back after driving it around. Also the upper rad hose tends to build up ALOT of pressure and antifreeze will start to spew out from the end that connects to the radiator. I have actually already replaced the LIM gaskets but it still didn't quite help. Here is a list of everything I have done:

Replaced:
Thermostat
Water pump
Upper and lower radiator hoses
LIM gaskets (and everything above it)

Flushed:
Heater core - flowing fine
Radiator - flowing fine

I was starting to think that maybe it was a head gasket but there is no coolant in the oil and I did a compression test and this is what I got:

Cylinder 1 ~ 160 psi
Cylinder 2 ~ 160 psi
Cylinder 3 ~ 190 psi
Cylinder 4 ~ 190 psi
Cylinder 5 ~ 190 psi
Cylinder 6 ~ 190 psi

The first two cylinders were a little low, but still within 15% of the highest.
I'm almost thinking that maybe the torque isn't quite right on the left side of the engine (or front, depending on how you want to look at it) and causing air to get into the cooling system. I am completely stumped on this one. Also in case it might matter, I have switched over to the "universal" antifreeze after flushing all of the dex-cool out.
 


I have seen an HG blow out between two cylinders. Caused no real damage..but man was it odd. I don't believe your numbers show a bad HG, however it's a 3.1 and my opinion on them is low.

Kinda posting to think out loud and also to bump ya back to the top for more opinions/info
 
Yeah if the HG was bad I would assume it would show much lower numbers and on different cylinders, considering 1 and 2 are on separate heads. I have everything taken apart at the moment down to the LIM, im going to recheck the torque on everything and see how that goes.

When I was putting on the new intake gaskets I had to get my car back together and couldn't wait for new intake bolts to arrive, i did use threadlocker on them but could this cause a problem with torque readings?
 
Even when these motors are running perfect there's always something that breaks or needs to be replaced and it always turns out to be the stupidest little thing in the hardest place possible. Well it seems you've ruled out just about everything. While you've got it apart check the coolant passages in the lim and heads, also check to make sure the pipe that screws into the back of the thermostsat housing is free flowing and the return line as well. Other than that I wonder if it could be something stupid like the radiator cap isn't holding the correct pressure or for some reason your fan isn't working or kicking on at the right time. And no the thread locker on lim bolts shouldn't be a problem, unless your going to take them off again it may be difficult to remove them. Taking this thing apart and putting it back together right is not a simple task. So kudos to you on that. Keep us updated on what happens.
 
Also, how do the plugs on your 2 lower compression cylinders look? I recently had coolant seeping into the front left cylinder "the one next to the water pump" check to see if the plugs look steam cleaned opposed to the others, although this is unlikely like mentioned before your compression probably wouldn't be that high....
 


Ok so the problem has been fixed. When I got back down to the LIM all of the bolts were off torque and acted like there was no thread locker on them at all! Anyway I retightened everything and put it back together and after bleeding it I have had no problem with it. So I am saying it is fixed until the next problem comes up
 
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