my gf's 94 corolla hasn't been coming up all the way to normal operating temp. the gauge barely comes up past the Cold line at the bottom, and doesn't get even halfway to the middle line like it typically used to (even when it was cold outside like now).

i really wouldn't care, i mean the car isn't overheating so can it be that bad? but the heat isn't getting as warm as it usually does either, and when its damn 20 degrees outside during the morning commute the heat is nice. so i'd like to get it back to hot like it was.

the radiator is full, and the reservoir is just below the full line. i was thinking maybe the thermostat is stuck open, so the car isn't heating like it should? or maybe theres just a bad sensor or valve somewhere? i was thinkin if there was a radiator or heater core hose blockage the car would overheat. car hvac stuff is pretty foreign to me though, for the most part. any ideas?

1/24/2008 9:49:22 PM

i'm gonna go with a stuck thermostat, it's only about $8 and only takes 10 min to drain the cooling system and change and maybe another 10 to refill it and bleed the air, if you open the cap when its cold, you should see water circulating if it is stuck open, if you cant tell by hat, feel the hoses, he bottom one should be at engine temp near the pump when warming up and the top one should be cool, if they are both the same, you need a new t-stat

1/24/2008 10:09:58 PM

my truck did the exact same thing, never warmed up to the operating range unless I gunned the shit out of it and even then it went back down, ended up the thermostat was broken and stuck open. Cheap part, and easy to get to on my truck, in a giant engine bay between the top radiator hose and the top of the intake manifold, but might be a little tight on the corolla, dunno where it is on those.

[Edited on January 24, 2008 at 10:48 PM. Reason : .]

1/24/2008 10:19:23 PM

My 95 Buick did the same thing coming home the other day. Sunday night so I had the heat running. If I turned off the heat it warmed up perfectly, after I turned it back on the temp dropped to its resting place.

1/25/2008 5:25:18 AM

anyone else? i'll probably try the t-stat first, its only $9 for her car

1/25/2008 2:28:29 PM

Thermostat. You'll probably need a gasket as well, but you can use that "make a gasket" stuff if they don't have one in stock.

It probably won't damage anything, but you're probably running on the rich side and getting bad gas mileage as a result of it.

1/25/2008 2:36:11 PM

turn the heat to ac, then back to air. for some reason that fixes it in my car. I changed the t-stat about 5mos ago too.

1/25/2008 4:30:09 PM