1992 Mitsubishi Galant heat not working well in cold weather

[ronbinmo]

Since the cold has hit, I'm noticing a problem with my car. It's a 1992, 2.0L SOHC L4. The cooling system seems to work too well, and when I turn the heat on, the temp gauge drops dramatically and the air becomes cold again. I also try to use the A/C for defogging the windows, but have to shut it off because even with the thermostat on hot, the air starts to cool. It has 99,000 miles on it, in mint condition, otherwise it has not a flaw and runs beautifully. Can someone give me an idea? Also, while it's idling, you can hear a slight mouse squeek in the belt....could that have anything to do with it? THANKS!

[mr bishi]

it sounds like your thermostat is jammed open (there designed to do this to prevent overheating)

[ronbinmo]

I kind of figured it out, but have not yet tackled the job. Usually I can coax some heat out of it, but I'm curious, would it make my fuel economy that bad if it's overcooling?
Has anyone changed an air filter on these cars? Who designed that HUGE PAIN IN THE REAR??

R

[mr bishi]

it can effect your fuel ecconomy as your car still thinks its running cold and is not up to its optimum temp

[ronbinmo]

Yeah, but I have a 16 gallon tank, and at MOST, when I went on a long trip, it got 400 miles to a tankful. That seems awfully low. How much do you think it would improve after I replace the thermostat?

[mr bishi]

i wouldnt like to say and there's no garentee that is the problem but sounds to be most likely. There are that many things can effect the running of the car due to computers and to many bloody sensors but if you take the stat out you should be able to see any gap as there supposed to shut fully when cold

[jsinton]

No, you guys are all wrong. My car also has a hard time warming up. But I think it's because it takes so much water to fill this silly little 2.0 L engine. It takes TWO gallons: It's simple physics... The motor is tiny. I'll bet if you run it down the highway for a while it's not so bad, right? And the thermostat will come up to the operating range, right? Yup.

[ronbinmo]

My car's coolant system is full. What you stated might make sense if, when I got the car warmed up on a stretch of highway, it stayed that way, or even within normal operating range. I actually tried this last night, and after having driven 35 miles, only got my car to heat up by allowing it to sit for a period of time idling. It's actually gone from mid guage all the way to just a 1/4 of the gauge (towards cold) in less than a minute when the thermostat starts to stick.

My fuel economy is also AWFUL. I filled the car up yesterday afternoon, and today, after having driven 90 miles, am already at a 3/4's of a tank. This car is mechanically, except for it seems the thermostat, in fantastic mechanical shape. It now has just a little over 100,000 miles on it.

Again, the only reason I haven't is because the air filter was such a pain in the butt, I want to make sure I have all the facts straight before I tear into it.

Thanks for your replies, does anyone happen to have the technical pages walking someone through replacing the thermostat in one of these finely Japanese crafted automobiles? (Mind you, I do LOVE this car!)

If so, please email them to me at ronb@cebridge.net.

Ron

[jsinton]

Ok then, sound like I'm wrong. The thermostat is really easy to change. Simply remove the two bolts holding the thermostat holder to engine block (It's at the end of the radiator hose on top of the engine.) Take out thermostat. Soak up some of the antifreeze with a rag or something. Clean the thermostat housing, and the place where it meets the engine block. Pop in your new thermostat. Buy some silicone gasket in a tube, and squirt it around the edges. Carefully put the housing back, making sure you have enough silicone around the edge to make a good seal, while not putting so much silcone to make a big mess. If you mess up, whipe it off and start again. Let it dry. Replace the antifreeze you lost.`

A test you might try is to slip some cardboard in front of the radiator to block the airflow. See if your car runs better, gets warm, and has better gas mileage. Then replace the thermostat.

[ronbinmo]

I will try that this week before my road trip and let you know how it goes, thanks!

R

[ronbinmo]

Ok, it's done and what a difference. Damn thing holds the temperature perfectly. Thanks everyone!