Truck won't heat up

[1993x]

Now that it's colder I've noticed my '93 ex will not warm up. The car had an overheating problem last summer which resulted in a blown head gasket and me doing a complete run-through of the cooling system.

I thought it might be a stuck stat but the heater blows luke warm and the needle stays at C no matter how long the engine runs. I take the car over the pass into Denver twice a week and even the high rpm in low gear type driving won't budge the needle off cold. I'm stumped.

 

[cloaked_chaos]

I'm betting that you have a bad water pump, which would also contribute to it overheating in the summer. When was the last time the water pump was changed?

 

[1993x]

After it overheated in the summer. That's not to say the new one isn't bad though.

 

[awdsixbolt]

had a similar problem in my 93 ex, flush the heater core and push fluid through it you probley have air trapped in there, sounds odd and dumb but i took a shot and it work out great, dont have to remove the heater core just disconnect the hoses to it hook up to random hoses to it and push fluid through till it clear (clean water) and then connect the heater hose that pushes the fluid to it and us the random hose on the other nipple start the ex with heater on high and wait for fluid to start coming out and its hot. turn explorer off reconnect heater hoses and you should be set

 

[92exp4x4]

Did you replace the sending unit? Over time they can get lazy and your truck could be running at the right temp, and if your heater core is plugged then you may be mistaken to it running cold.

My green '94 does what yours does, but it has good heat.

I put a new Motorcraft unit in my 94 Eddie and the difference in the gauge movement was surprising. It will climb from N to almost M and oscillate with the opening of the thermostat now, when before it acted just like yours.

 

[wood1]

I always thought that a thermostat stuck open would cause an engine to run cold.

Excellent point about the defunct sender unit though.