1G Cooling system issues

[turbonitisdan]

recently got a 1990 talon. The car is bone stock. When I got it i noticed the fan was hard wired to be always on. I figured it was just a relay or something the previous owner was to lazy to replace. While driving it home I noticed the temp gauge would barley move in between the first 2 marks all the way to the left on the temp gauge, so barely registering and temp at all on the gauge. while driving and in traffic remains the same just barley moving the gauge. My first thought was the temp sensor was bad. I turned the heater on and it was just barely warm, I also gave the the upper radiator hose a squeeze and it had just a little pressure. I went to check the coolant level ( after driving for 15 mins) and when i pulled the cap it had a little pressure but not much and when it came off it sounded like a waterfall or fluid moving about in the radiator. It was maybe a quart low on coolant so not much and it didnt ever boilover while driving it around. I checked my oil to see if a bad headgasket was the issue but there was no coolant in the oil and the car does not smoke anything idle or WOt. It was cold this morning and after 10 mins I figured to unwire the fan to help it warm up. I did this and after a few minutes the temp gauge actually moved. It went up about a quarter of the gauge (under the temp symbol in the gauge just past the first bracket marks). I turned the heater on and it was warm as well. I set off in the neighboorhood and the gauge came up alittle more. It then started to boil out of the overflow on the thermostat housing into the resouvior. The gauge was still a quarter of its sweep still well below where the gauge normally sits. I pulled over and turned it off, it stoped boiling and the upper radiator hose had pressure in. I rewired the fan up on the side of the road and started off again and the temp gauge went down after a few minutes all the way to just barely reading like it usually does with the fan hooked up. The heater was barely warm like before when the fan was always running but the car ran fine for the rest of the tim i drove it. I confused on what my problem could be I thought the temp sensor might be bad at first but with the heater coresponding with what the gauge says im starting to think its something else. any ideas???
thanks dan

 

[96 420a-t]

Replace your thermostat and rewire fans back to stock or get an aftermarket thermo switch. Do you cap just as pm since they are cheap. If your guage stilldoesnt work look at replacing you sending unit.

Pm= preventative maintenance

 

[turbonitisdan]

i was thinking it might be the cap just how it would lift the cap and boil out the coolant when the gauge would read just below normal oper temp

 

[96 420a-t]

The spring gets weak so the caps ability to hold pressure is weakend. I would point fingers at your thermostat first. If your engine is not warming up then it is most likely stuck open or missing.

 

[turbonitisdan]

so even with the fan on constantly it should still get warm, or atleast warmer then barely moving the gauge

 

[96 420a-t]

Yes, your thermostat should stop the flow of coolant not letting the car cool down. In theory it is supposed to bkeep your engine at a minimum temp.

 

[turbonitisdan]

thanks for the info, now that i look the thermostat housing it has a ton of rtv sealer around it i bet it doesnt even have a thermostat in it

 

[96 420a-t]

That ll do it. Try that first and update.