Strange over-heating problem.

[Turbo Juice]

lets start with some background. fresh block, new HG & studs, new thermostat, last time i checked compression was good. stock radiator, new fans, not terribly large IC but pretty sure there is plently of room for air to go above it. also my car is very conservative right now. 14b with all supporting mods. but i dont drive it hard anyways.

ok so most of the time my car does not get too hot. this is only happening when i am on the highway for about 30+ minutes. in an instant the temp will shoot up and piss out coolant. after that it is low on coolant it and the temp get dangerously high pretty quickly.

i cant figure out why it gets that hot only on the highway and after a long period of time.

please this is driving me insane, because i make trips often!!!

 

[talon96tsi]

Is it the stock thermostat?

 

[eclipse_20g]

When the last time the car has had a complete coolant system flush? I'd start with that.

Next, I'd check connections and sensors on the thermostat housing, and the thermostat itself.

 

[GOTLAUNCH?]

Another vote for the flush here. But if your stock radiator has enough miles and gunk it in it could be clogged period. How does your Upper radiator hose look like? does it get all bloated up when you overheat? let us know

 

[500orbust]

Also, did you burp the cooling system correctly? What kind of fans are you running, and are they wired in right?

archie

 

[Turbo Juice]

well at the begining of the summer i drained the cooling sytem and put fresh fluid in. thats when i did the thermostat. i got one that was 10 deg cooler. so is that 170 i think. yes it is the stock radiator with 80k on it. yes the upper radiator hose plumps up a little.
and yes i think i did the system right. you are just suppsed to let the car run with no radiator cap on it right.

oh i forgot to mention i have a greddy rad cap.

 

[ITSME4G63]

did you run the car with the heat on for the first 10 mins after warm up? this lets the coolant cycle, the point of it is that when the coolant cycles you can top it off after the cars been cooled down preventing air to be trapped in the system.

 

[gsxeclipse102]

if your overflowing coolant into your overflow bottle then either your head gasket is blown(most likely) or the radiator cap is bad. do a leak down test and see if you see bubbles in the coolant.

 

[GstRacer]

i would put the oem t stat in there, those auto zone 170s are junk. also i would drill at least one hole in the outer ring of the new t stat that will help out a lot!!!!. it sounds to me like after long driving the t stat is just sticking closed, because its no a good brand. drill a hole or 2 and a new oem t stat and you should be fine. thats what i did and i run like 180 on the highway and i have a 12" by 24" by 3.5" FMIC

 

[Eclipsethis90]

I run an OEM with holes drilled also and it lowered my temps about 2-3 degrees after i installed my FMIC. Then a little ducting inder the radiator to channel air though the rad and I have a rock solid temps city and highway.

 

[blue1]

Stick with the stock thermostat and just check if the fans are blowing or sucking through the radiator when they switch on!!

 

[fourreGsixty3]

Jack the front end off the ground, and let the car run with the rad cap off, this will let the air come out of the coolant system quicker. Like the others said go back to an OEM T stat, and drill 2-3 holes in the outer ring, like shown in the picture. Also do you have ac? If so do you use it? If not, I would pull it and get that crappy ass ac condensor out of there, that will allow more air to get the radiator. Also look at the radiator, if it is going whitish in area's it is time for a replacement. Also pressure test the coolant system to make sure there are no leaks and no hoses are ready to burst. Also you said that you installed new fans. Are they pushers or pullers? What is the cfm for them rated at? Also do you have the stock heat shields on? Both lower and upper? Also put some water wetter into the radiator.

Dustin