I live up in cold edmonton alberta and just got my car going this year for summer. The temp outside has been around 26 degrees and my car is heating up around the 3/4 mark or higher. I had the coolant flushed last summer and i have a manual fan switch. i pulled the thermostat out and checked if it was working. The fans are working both in low speed but only one in high speed ( dont know if that is normal ). The rad cap seems to be fine also.
Any idea's?

95 z28 6 speed, mostly stock with mild cam upgrade.

 

During what conditions does it heat up to the 3/4 mark? While driving on the highway? Sitting idle?

 

I just had it out. it heated up in about ten minutes of driving around 60km, it does the same thing on the highway. i blew the rad out just before i went for the drive, it didnt help.

 

When you say you blew the rad out, do you mean you flushed it? If so, did you fill/bleed the system correctly afterwards?

Is the air dam intact under the radiator to direct air over it while driving?

 

26 deg C or F as I have a feeling you mean C. Probably need to bleed that thing again as it can be tricky to get all the air out of the LT1 cooling system sometimes.