Thread: Overheating with the A/C on on extremely hot days trick

Anything over 90 degrees on the highway it pegs 250 on the guage and the factory guage is up there. I have a MS Design bumper cover but the airflow is the same. Trust me with the headers under there it is an inferno. I opened the hood a few days ago and a friend was like DAYUUUM! LOL.
I need more cooling, I am going to try Thermo-Tec header jackets to see if that helps with heat control. It is like stale are not circulating at certain temps.

I have had a Modine, CSF (Pure leaking crap) and this Silla. The Silla actually pegs a lot faster than the prior, but the sme sympton none the less...

Hmm thats odd, def have some kind of issue. I personally would have the headers ceramic coated, looks good and cuts heat. Unless you have HotShot headers which I believe were already ceramic coated.

Also at speed on the highway the fans wont come on since the airflow should be sufficient to cool the engine. You could have a failing water pump since it only happens at higher speeds.

Had the water pump replaced and still the same issue. It has been this way every summer for the past 9 years...

Kind of a stupid question, but are you sure your gauge is accurate?

Very. Cause the A/C compressor cuts off as well.
The Autometer pegs before the factory guage. That sucka is hoooottt.

Does this look like a restriction?

Over a 9yr period you've done what most have probably already suggested. My thought would have to be to look at parts that are the same and consider them possible issues. One thought I have is your block, well cooling passageway(s) in particular cause it seems you've got some kinda restriction somewhere. The head gasket thats on there, could it be blocking the wrong hole and its just held over time? Im sure ya see my point, Im just saying there has to be a "why" it overheats after 9 yrs, after all sorts of things have been done... Im not saying what your problem is but offering up some other idea, well other than your car is possesed by some kinda heat demon! LOL

@NX2KTuner I totally agree. I just put a header jacket on and it still pegs, but the underhood heat is totally cut down:


The A/C compressor did not cut off though. So that may have helped some. I know I need a new motor. That will come in time. I just need this dead motor to run as good as possible to make room for a tight one.

Googling "overheating at highway speed with A/C on" comes back with a lot of hits and different solutions. BTW, did I mention it does not overheat at night? Only during the daytime.
http://www.ultimatesubaru.org/forum/showthread.php?t=62061

One thing I observed yesturday. The NX has the powersteering lines in front of the condensor. And they get really hot. Would that contribute to extra heated airflow?