I'm at my last resort with making a thread on this topic, I tried everything I could find to solve my overheating issues. Here is a summary of the situation

My new engine and turbo setup has never once gone above normal temperatures until a week ago when the temperature reached 95 degrees (for Maine, this was incredibly hot). I was boosting around that day and didnt even notice my temps until it was almost redlining the gauge. I let it cool off and checked my coolant and stuff. Everything seemed fine. Since then, every time I boost hard (4th gear redline) my temp gauge shows slightly above normal temps, about half way up the gauge. As I continue driving, the temperature decreases to normal as long as I dont boost. Now yesterday I took a long 30 minute drive in the car almost completely staying out of boost. After about 20 minutes of driving my temp gauge began to creep up to halfway and stayed there until I pulled over and let it cool down.

On the highway while doing hard 3-4 gear pulls, on long trips in hot weather, and occasionally at random, my cluster water temp gauge will rise to about 1/2 up the meter. The car will cool down at moderate speeds if I stay out of boost. On multiple occasions, the car reached 1/2 temp just from idling.

What I have tried so far:
Manual radiator fan switch constantly running
Compression test (perfect results)
Adding coolant with 50/50 mix
Tested thermostat (diaphragm opens in boiling conditions. also tried running car with thermostat out and car overheated at idle)

My last idea was to test my radiator, but I'm not sure how to do that. Right now there are zero signs of a blown headgasket other than the overheating. Can anyone help? Thanks in advance.

 

The main reason why I am so confused is that this just happened for the first time suddenly, and has been happening constantly since then, so it leads me to believe that a part is broken. I just cannot figure out whats wrong.

 

this is what happend to my b16 suddenly while street tuning. we got it tuned enough to take it to the dyno. while on the dyno the temp was rising and falling just like it had been. just like yours. mine even blew my radiator in half. we replaced the radiator because it was the stock plastic one. not 20 mins later on the dyno then engine locked up. The culpret was the oil pump. It must have been going out for some time causing my temps to rise

 

It might over heat with the t-stat out because the water circulates to quick to let the radiator cool. It could be a problem with the sensor or gauge but it is unlikely by the sounds of the symptoms.

 

possibly your fan just isnt blowing as hard as it used to

 

Thanks for the replies.. but wouldnt the fan be irrelevant at 60+mph? The fan blows well but blows very hot air.

 

Have you checked yor water pump?

 

Is there a way I could test it?

 

Drain the old and see if it looks milky. If it is you might have a bad head gasket.

 

There is zero coolant in the oil, and zero oil in the coolant. Thanks for the suggestion though.. compression came up good so I can only assume the headgasket is still good.

 

check your rad cap.

 

I have been "checking" the cap every time I have the radiator open.. but is there a test for it?

 

Reinstalled my thermostat today. Refilled coolant. Overheats almost immediately on hard pulls. I cannot find any signs that something is wrong. I will be installing an oil pressure gauge tonight to test oil pump. I am planning on going to an event with the car on Saturday. Can anyone help me preform some other tests to find out whats wrong with this piece of $hit?

 

if you live next to an advance auto parts or auto zone go and rent the coolant pressure tester and test your system. if you have pressure drops you have a leak somewhere or something else is wrong

 

you can also test the coolant it self for combustion, its a little strip of paper you dip in the rad. when my car was doing this, it was due to a crappy t-stat. installing a oem honda one solved the issue IMO 40 bucks well spent even if it turns out to not be that

 

Are you sure you can trust the guage? Maybe try installing a new coolant temp sensor.

 

Thanks for the replies. I'll get a combustion test kit, a pressure tester, throw in my old gauge cluster, and try to find a friend with a coolant temp sensor tomorrow and report back.

 

I second doing the exhuast gas test. sounds like your head is lifting under boost. have you considered running arp head studs?

 

my vote is headgasket related. had the same thing happen to me on my old boosted y8. new hg and some arp studs fixed it

 

My car STILL to this day just doesn't like hot weather. Car runs fine until 85-90+ degrees outside. Its not my coolant temp like I thought, but instead air temps. I put a SPAL puller fan on with a shroud, and run it constant, and put in a mishimoto low temp stat. My coolant temps dropped DRAMTICALLY, but still air temps were too hi. I am so fustrated with how things flow and what not, so I took my bumper off and the car NEVER overheats now.

Make sure you do the basics, and make sure the coolant is bled properly, make sure cap and stat are working right, etc.....

You should NOT be running 50/50 mix, if your running @ event you ESPECIALLY should not be running that much coolant. You only do that in the winter time for the street. You need to run 90/10, 90% being water and the rest coolant. That alone should help, when it's that hot out.

Try running the bumper off the car and see what that does, fixes my problem, at least for the track. If you are able to hook up a laptop and look @ the settings, look @ your coolant temps, and air temps to see what is what. You may be heat soaking (air temps), and not actually overheating the coolant. Try that stuff, and if your worried about the head gasket try a sniffer. But yea you should DEF. be running head studs......

 

Yes the car has ARP head studs and less than 500 miles on the headgasket. The overheating no longer has anything to do with the weather, it over heats at all temperatures. I will add more water to the coolant mix.

 

you need to completely drain it out, and re-do it 90% water. How are you bleeding it? If you don't have the bleeder nipple on the coolant neck how are you doing it?

You need to put the fan back to run off the stat, top off the coolant on a cold motor. Leave the cap off, and run the motor until operating temps. Let the motor run until the fan kicks on, as the stat is now opening and flowing the coolant. I usually let the fan kick on at least 2 times, then after or during the second time, you slam the cap back on and should be good to go.

It is a poss. bout the gasket. What did you torque it to?? Arp's should be about 80lbs i beleive. Try putting a low temp stat in it if all else fails, they aren't that much, and it will help coolant temps reguardless of the situation.

 

pull off your front bumper and drive it around and see if it still overheats. i had a boosted sohc ef and drove around w/o a bumper, as soon as i threw it back on it would overheat =(. this was in 90+ degree weather.

 

I second this, if the block is not sleaved and you are boosting it is building pressure that is getting by the head gasket causing overheating. are you blowing coolant thru the overflow bottle.

 

Okay.. I've finally found something wrong. When I first pressurized my radiator, I immediatly found that the upper radiator hose was loose and leaking where it connected to the engine. I tightened the hose clamp as tight as it would go and drove the car. At first, I thought everything was fixed. The car took TEN 3-4 gear pulls before it started to overheat. And, when it did go above normal temps, it dropped back down to normal VERY quickly.

I am now in the process of testing the radiator again. I pressurized it to 15lbs and within 60 seconds it was down to 14lbs, then 13, and lower and lower. Does this make sense that a leak in my coolant system would cause overheating like what I've been experiencing?

How can I find the other leak? I do not hear or see anything leaking.