Engine NOT heating up - any ideas???
 

I just acquirded an 87 GT 5.0 and it has an aftermarket temp gauge. The highest it has ever read was 150, and it took FOREVER to heat up to that 150. Took off the thermostat housing and pulled the thermostat out and it was stuck completely open. I was stunned at first...wondering "what the hell is this thing???" Then realized it was stuck open. Nothing was lodging it open, seems like the something happened to the spring or something. Anyways....changed it out for a 195* Mr. Gasket thermostat. The car heats up quicker but it doesn't go past 150....just like before. I've filled the radiator, bled the system, etc. I couldn't figure out the problem.

Took it to a shop and they said the radiator core was about to blow. It leaks and the radiator also leaks on the side. I never see any green drops anywhere....but there are some white marks, as if it had leaked. The top radiator hose doesn't get hot.

So my question is......would a bad radiator actually cause the car not to heat up and hit the 195 mark? I'd think that since the car was running for so long, the coolant in the block would heat up and at least make my temp gauge (mechanical gauge) to reach 195+. Wouldn't a bad radiator cause the car to OVERHEAT?? If it needs a new radiator, it needs a new radiator....I can get one no problem. I'm just wondering HOW a bad radiator would cause it not to heat up or the radiator hose to stay cold, etc.

RE: Engine NOT heating up - any ideas???
 

Soumds like a bad (aftermarket) temp gauge, or temp sensor. crank the engine and let it run for about 5 minutes. touch the intake with your hand,...(be careful). you should be able to handle the warm intake with no problem. if it's to hot to touch for any lenth of time,..(5seconds) remove the thermostat, or replace it with a 195 or 180 degree new part. If after that you have the same problem, bypass the heater core (it may be stopped up). retest.

you can test the water pump by removing the radiator cap at operating temp (be carefull agian) and looking to see if the water is circulating in the radiator. (it should be a very rapid flow).

Tnx
k4wsp