My setup right now is an 1989 ef with b16a high compression.

my car currently overheats with i drive for more than 10-15 mins on the highway at the speed of 100km/h or more and when i drive up hill. The car is fine in the city during stop and go traffic going at a pace of 60-70 km/h. I do have the fan running on constant.

I have replaced the Thermostat but not the temp sensor. and my coolant runs low ever so often.

Does anyone know what my problem is??

 

Sounds like you should check the water pump.

 

if your coolant is disappearing, it's either an external leak or leaking into the cylinders, the cylinder in turn puts air into your coolant lines restricting flow and causing your engine to overheat.

Your headgasket is probably blown. Also do check your waterpump, after you remove your head and replace that headgasket.
And if your temp needle has hit that lil red line, (which you should never let it do) you need to have your head resurfaced and hopefully it won't be warped beyond repair.

 

waterpump is probably going, and leaking out of the weephole in the pump

 

That is interesting to know....Thanks for the advice. so the temp. sensor has nothing to do with this.?

 

yeah dude check your waterpump

 

on average no,
1. replace coolant, look for oil in coolant
2. with car running take off ur radiator cap and see if thiers a steady stream of coolant going along
3. does ur car smoke at all, turn on ur heater while driving and see if ur temp needle goes down.
you've checked everything else so its eather ur headgasket or water pump i would believe.

 

the needle does go down when i blast the heater. and i do replace the coolant and top it off once or twice a month.

so maybe i'll do the water pump first then if its still over heating i guess i'll have to replace the head gasket too.

 

The car doesn't smoke at all??

 

are ur fans turning on???, might as well check the water pump.

 

FANS are always on and there is no oil in my coolant

 

yeah well then i'm gonna go with water pump..

 

Thanks for the advice guys i will go ahead and change my water pump and hopefully my overheating will end so i can drive my car without having to blast my heater in 100 degree weather.