Cooper04

I have a 1996 Toyota 4-runner sr5. It has 148,000 miles on it and I recently had a rebuild at 138,000 miles. I now get a roar when I accelerate and my car temperature guage is not heating up to it's regular temperature when the heater is on. The termostat has holes drilled in it (Solved overheating problems after rebuild). I was wondering if it could be anything else or is it definetly the thermostat. I was wondering if this can cause any harm to my car's engine?

Tacoma Dude

Now I could be wrong here but I believe when you have the car heater going the heat transfers from the engine to the cab.
This is why they say the best thing to do when you're driving in hot temperatures and in danger of overheating is to turn on the cab heater.

This will slow down the temperature climb of the engine compartment at least.

Anyhow, that's what I THINK is the reason - I'm sure someone else can pitch in and let us know if I'm right or wrong

TechWrench

Just a thought, you mentioned a 'roar' when accelerating along with the temp problem. Maybe you have the fan clutch stuck/frozen. If the fan is turning at 'full' speed all the time, this would explain the roar and the low radiator temps.