Experienced people know that block testers are unreliable so waste of time and money.




Retorquing the stock bolts usually works.

 

Still no white smoke?
It you replace the thermostat make sure to buy an OEM one.

 

Experienced people also know that a block test is just one easy, cheap test of many tests that one does when diagnosing a head gasket.

 

It doesn't work.

Just like a compression test won't find broken ringlands on pistons.



When you get a bit older............you might figure it out?

 

I had it leak down tested and it showed that the head was just lifting, fixed with arp headstuds

 

I had the SAME EXACT symptoms a few months back. The engine would push coolant under boost. Driving around town and light throttle was perfectly fine all day.

I would highly recommend you pull your head off and have it checked by a machine shop, just throwing studs at it is just a bandaid. Once you start pushing exhaust gases into the coolant system it wipes out the viton seal of the fire rings pretty quickly.

BTW my head was warped about .002" from the overheating.


Here's my old headgasket, note the fried fire ring on cyl 1:




Here's my head after a ~.001" shave, note the warped area is in the same exact spot as where the fire ring was fried:




Another .002" and it was good as new:

 

I had a similar issue on my evo 8. But at a 1/4 mile track day.
I called it head gasket issue.

There is 2 types of head gasket issues.

1 that is severe and mixes fluids.
2 one that only leaks under boost from combustion chamber into cooling system.

Upon removal of head i found that my thermostat was old. The upper rubber that holds thermostat pintle or valve in center was decaying and probably making my tstat stick.

A head gakset tester isnt the best of tests. Ive been working on cars for 6 years in a shop and have successfully found 1 bad head gasket that failed that dumb test of sniffing the coolant and the blue fluid turning yellow. That head gasket was so bad i found coolant in the cylinders.

 

Diagnose it like this.
Leaks? No?
Good compression?
Fans turning on?
Radiator restrictions? Likely no
T stat opening good?

Remove head and youll likely find crusty brunt coolant along head gasket in areas other then coolant passages

 

I have EXACT the same issue, was at Buttonwillow and the evo starts overheating after 2 laps.

Driving on street doesn't overheat but water in the radiator keeps getting lower after I fill it.
I found my t stat was bad (rusty) replaced it, the same issue still there.

 

I threw a bunch of parts at it (radiator, thermostat, rad hoses) and then had a shop do a leak down test; they thought my head studs were stretching. They recommended I put on new ARP head studs, which I did. I went to Big Willow about a month or two later and still had the same issue after about three laps. It turned out to be a hairline crack on the head gasket just enough when driving on the street; there would be no rise in temperature. 4b11slayer was totally right ^