SR Overheats

[DataXUnknown]

Well recently I just finished my SR20 swap into my s13. It drives nice locally, but when I get onto the freeway the temperature slowly starts to rise, eventually just about all the way. Then if I stop and let it idle on the side of the road, it does not go down. It will only go down if I turn off the car and wait it out.

It's wierd because I drive locally just fine, but its like when I hold a constant 60mph or above it will rise. I have a stock radiator, it's a bit banged up but still works with no leaks, I burped the radiator, the only thing that I noticed is that I am leaking a very small amount of coolant. In one of the hoses behind the engine (right near the heater hoses) there is a bit of rust on the actual metal of where its leaking. To fix that I am either gunna get some more hose to cover it, or buy some leak stopper stuff at wal mart.

any other ideas of why it only overheats on the freeway? i have a smic but i cut a hole in my stock bumper just for that.

[sac]

could be your heater core is toast.
if your heater core is not flowing coolant like it should, it will restrict the coolant flow. It can happen even when not running the Heater. But not likely to. Could be a T-stat not opening up enough.

dont know if that will help. Just giving thought since nobody else is.

[IRN]

check your thermo? kinked heater hoses? faulty temp sensor?

[g6civcx]

Check coolant level. Carefully retighten heater hoses so you don't crack the fittings.

[DataXUnknown]

the heater hoses are just recirculating. I am not running heater or AC. I took out all of the heater components and AC components. coolant level is good. gunna check temp sensor next. thermostat i believe was checked already by my buddy but i will double check. thank you for the input guys.

[DataXUnknown]

i dont have a heater core or a BOV (still waiting from Apex >=\) and i think maybe the thermostat is getting stuck. my radiator is a bit banged up but it should still be good..

[eulalia]

if you have a leak it means, air is going into the system

your sr hateeeeeee air!!! they will over heat super fast if there is air in the system

fix that leak and that could help the situation

[yfz460]

Sounds just like a buddy of mine's Liberty. When the engine was revving higher (highway speeds), the actual impeller would slip on the water pump shaft because of the resistance in the cooling system and it would overheat until he slowed down and shut the engine off... so long story short, if all else fails, check your water pump!

Yes, I realize our impellers aren't pressed on plastic fins, but hey it's a possibility (after all others are ruled out of course).

[JFoxx]

i have the same issue....only overheats on the highway at a constant speed for awhile......i have koyo rad, no leaks, good coolant level....its been that way for months....no idea whats wrong.....(and i know its not the sensor)

[legacy927]

what do you consider overheating? My temp gauge (STRI) is showing btwn 180 and 190..some say its over heating, some say its not...I've been driving it since last Nov. and the car didnt act up..

[fliprayzin240sx]

+1, if coolant is leaking, then you're introducing air into the system.

[stupid nissan]

when it is cold take off the rad cap and start the car. let it warm up to temp and fill till full. thats how i get the air outta the water system. also check your water pump.