Ok so I just recently purchased a 92 hatch with a b18c. The car drives perfectly fine and has no codes but as soon as I hit vtec the temperature rises to about 3/4 and goes back down if I pull over. The temp goes back to normal quickly and it doesn't overheat if I idle for a long time. It's also a 2hr drive from where I bought it so no overheating problems during the long trip. The car's temp only goes up when I hit vtec. I also checked the fan and it doesn't come on at all. Does it have to do with the fan not working? Please help! TIA

 

you just answered your own question.

 

If it has to do with the fan then how come the car does not overheat at all when I'm not engage in vtec? It can idle all day long and drive 2hr+ and the temp will not rise at all.

 

have you bled your cooling system? checked for leaks?

 

No I haven't done any of those yet.

How come the car doesn't overheat if the fan doesn't turn on but temperature only rises during VTEC and drops back down as soon as I pull over.

 

because your not putting stress on the engine. just hard wire the fan and tell me it didnt work.

 

Do you understand what VTEC actually does??
It's not a magical switch that when you goose it makes it go faster, its changing the valve timing by flat out disengaging portions (or whole) of your camshafts, this effectively adjusts some if not all of your valves causing your engine to operate differently, this could include but is not limited to increasing comp ratio, possibly advancing timing some and many other things.

In short, when you floor it, engines get hot... if you don't cool them properly, they will asplode'.

 

Get your fan working properly. Check the fan/fan switch.