Overheating when idling. Just replaced blown headgasket "Cometic" been blown in 3 cylinders. Now engine still overheats unless AC is on (2nd fan on).
Would you think its a Thermostat that is acting up? (We let all the air out of the coolant system). Is there anything else that can cause overheating?

Thanks for advise.

 

Check to see if your thermastat is opening.... just feel the lower coolant hose to see if it gets hot after awhile....

 

oh, yeah fan also has to kick in when you bleed the coolant.... and all air bubbles are gone....

 

Is the radiator fan kicking on as it should? Any bubbling in your coolant resevoir? You could try the thermostat since it is cheap and easy to replace. Your positive you got all the air pockets out of the coolant system? If you are sure on those i think you still have an issue with your head to block mating together smoothly. Why did your headgasket blow? Did you get the necessary parts machined such as the head to ensure a smooth surface? Metal head gaskets need a smooth surface to seal correctly (50RA or more). Good luck.

 

HEadgasket blew cause head was o-ringed and it didnt work with cometic headgasket. So now head was redone and looks like a mirror finish. I still have issues for some reasons when I start the car it would misfire for few seconds. then no issues at all.

I got all the bubbles and air out of the system. Can it still be new headgasket? I just cant figure where my coolant would go now, cause i lost about a quart in 50 miles again.

 

Sounds to me like you still have a sealing issue. Did you make sure the block surface does not have any imperfections also? Good luck.

 

1.) Make sure the radiator fan is coming on
2.) Do a compression test.
3.) Dump the contents of oil and examine to see if any coolant has mixed with it.
4.) Dump the contents of your coolant and examine to see if any oil has mixed with it


If everything checks out with the above 4 steps move on to step 5:

5.) Check thermostat operation:

 

A couple things.
If you have an 03 the fan controllers were problematic, IIRC there was a recall on some.

You have ARP studs in there? What torque did you use and how hot have they gotten?
YOu need 85 ft lbs. of torque IMO with that head gasket. If the ARPs were reused and got hot they are possibly overstretched now.

 

Sounds like fan not working. DID YOU PLUG IT BACK IN?

If it doesn't overheat with the AC on, its because the AC fan is sucking enough air to draw heat from the radiator.


Fix your fan.

Then put in a stock headgasket.

 

Check the plugs to see if they have a greenish tint to them. That is a sign that you are burning coolant within the combustion chamber. Does the car blow white smoke? Also, the fact that you lost a quart of coolant may just be the system getting rid of all of the air. Fill up the reservoir and mark the level with some tape. If it no longer goes down when the engine is cool then you have no leak and the system has been purged. This was very common on my Z when I would drain the coolant to have it continue to drink from the reservoir until the air was gone.

As people also stated, check to make sure the secondary fan is kicking on at the desired temperature.

 

My car was recently overheating at idle and also losing coolant.. I kept a close eye on it and every few days I'd have to top it off.. Finally, I started noticing larger puddles of coolant under my car in the garage every morning, and the water pump had started to let a constant few drips leak out... Had the water pump replaced under the TSB and no more overheating problems... Might be worth checking out..

 

Ok, Thanks for advises.

Here is whats going on. When Idling temperature would go up to over 100C (boiling point of water). Fan Kicks in, but when iverheating does not seem it blows hot air out, so it might be thermostat.

Also brand new OEM headgasket was installed, and it still goes through qt of coolant in about 50 miles. (head was resurfaced).

There is no coolant in the oil. So far I am confused of where my coolant goes and if it get in the cilinders then why?

ideas pls.

 

are you leaking any coolant??? also i would just order a new thermostat and replace that... also maybe get a cleaner for the cooling system... also check your water pump see if that is leaking.. when it goes bad it starts to weep...

 

NOp no leaking anything. Looks like the problem is bigger. Today did cooling system pressure test to like 25PSI and cilinder 1-3 got coolant in. So looks like my Buschur Ported head been defective. Looking back this condition always been there as it had been pain the axx to tune with aem cause coolant temp would flucuate. Sad thing is I only have like 5,000 miles on it with low boost 22PSI or so.

 

This doesn't neccessarily mean the head is "defective". Its sounds like your block to head mating surface is warped. Was the head resurfaced? Who installed the head studs? How did they install them? Was the block decked or checked for warpage as well? The coolant is getting into the cylinder because the headgasket isn't sealing correctly.