We have drove this car for 2 year with barely any heat and a temp. gauge that never went above 1/4. So one 15 degree day I decided to replace the thermostat. Wow had awesome heat. I also replaced the temp sending unit. Gauge works also now. Drove home from work and no problems. That night we went out and noticed the gauge started to climb whilst going up a very small grade. So I went up a big hill and the gauge jumped to the red. I kicked the heat on hi and we started going down the hill and it went down to normal temp. If the heat is on hi, it does not heat up as much. I put a lower temp thermostat in (180) and drove it some more and it still raises above half going up a big hill but it is a lot better. I bleed the coolant system and got no air. Is there a lower temp thermostat? Once spring comes put the heat on hi is not a option. When is does overheat and the heat is on hi, I'm afraid the vents are going to melt.

 

put an oem thermostat back in. bleed the cooling system. are there any leaks? what condition are the radiator and rad cap in? is your cooling fan coming on?

 

^this^

also did you make sure to install the bypass in the right direction (up, down, left, right) on 94's i'm pretty sure it goes up.

when you bleed the system again jack up the front of the car a little bit and rev the engine some. also try to sqeeze the coolant hoses to get any other air out.

 

Fans come on when it heats up. I'm pretty sure all the air is out of the system. There are no leaks. I did a timing belt and water pump over last summer and the radiator doesn't have any cold spots on it when its hot. I have a parts car that has a radiator in it . I might try to swap them. Is a ex radiator the same as a lx?

 

The problem was the thermostat I put in. The one I took out was 78c (172F). I put a 195 then tried a 180. I found a 170f and its been fine ever since. Have good heat and no overheating anymore. So if anyone needs a 195f or 180f thermostat, I hook yinz up