Runs Too Cold

**LingLing** · 03-29-2006

Hey everyone. Well, here's the problem.

1990 Plymouth Laser RS-T..STOCK

Our temp gauge is suppose to sit straight up and down when at normal operating temperatures, right? Well mine sits right above the 1/4 hash mark on the gauge. Sometimes it will creep towards straight up and down, but really only makes it to a position similar to 10 o'clock. I thought my thermostat may be stuck open, but when I examined it, it's clean, and looks like it was replaced before I got a hold of it. The engine doesn't smoke and shows no signs of overheating. I do have a SMALL coolant leak coming from one of the heater core hoses, but I don't know why those would contribute to an engine running too cool. Suggestions are good! Thanks for reading! Sorry it's so long.

-Jason

**Kracka** · 03-29-2006

Replace the thermostat again with a quality Mitsu one, a lot of the time the aftermarket ones are pretty crappy and wear out quickly. I've encountered a few that were junk right out of the box. Have you tested your coolant to make sure its near a 50/50 mix? Also wouldn't be a bad idea to hook your car up to a Datalogger so you can get an exact coolant temp reading, maybe your temp gauge sensor is just faulty.

TheBlizzard · 03-29-2006

Do you have good heat?

joesushi · 03-29-2006

The night that I drove the car the temp was ok, it rose to the 50.99% mark (every turbodsm i have ever owned/driven has operated similiarly)

it got pretty dropped down to ~45% when i drove it, but i assume that was because of a bad thermostat.

But this was a week ago, and I am curious as to WHY it is misbehaving now......you can put your hand on the engine, and if it is really running that cold you will be able to tell, but if it hurts your hand, then its probably running at normal temp, AND SINCE WE JUST DID AN ENGINE PULL, THE SENSOR/WIRES COULD HAVE BEEN DAMAGED/BROKEN -just a thought...

but for now, replace those gay ass OEM coolant lines with new ones, and get t-clamps for everything....I assume that those old hoses are the ONLY place your engine is leaking now (aside from the valve cover gasket leak)

so fix everythign you can, hammer out the easy things, did you get the wheel bearing replaced yet?

**LingLing** · 03-29-2006

Quote:

Originally Posted by TheBlizzard

Do you have good heat?

yep, good heat.

i will replace my thermostat tomorrow and get back to you all. If that doesn't work, I'll try to find someplace/someone with a datalogger and work from there. Thanks for all the suggestions.

-Jason

GVR-4579 · 03-30-2006

If you want to test a thermostat you can just stick it in a pot of water on the stove. Just incase you do want to test it

**LingLing** · 03-31-2006

and at a certain temp. it should open, correct?

**Kracka** · 03-31-2006

Quote:

Originally Posted by GVR-4579

If you want to test a thermostat you can just stick it in a pot of water on the stove. Just incase you do want to test it

Unless you have an accurate thermometer in the water that won't show much of anything. We already know its opening since the car is not over-heating.

Febo · 03-31-2006

Too cold of a thermostat range, or the thermostat is just staying stuck open. Hear about this alot actually. Heck, my GSX is doing it right now.

**LingLing** · 03-31-2006

Quote:

Originally Posted by RLFebo

Too cold of a thermostat range, or the thermostat is just staying stuck open. Hear about this alot actually. Heck, my GSX is doing it right now.

So, maybe I have the wrong kind of thermostat in? But why would it be stuck open? Wouldn't it be stuck closed, if anything?

Febo · 03-31-2006

Well, stuck open... weakend to where it will open at low temps... same thing. But if your not over heating, its not stuck close, its just not closing period if your overcooling.

**LingLing** · 03-31-2006

Okay, well I'll throw in a new thermostat Sunday, and see what happens. But I also have to re-do my oil cooler lines too. blah...I'm truely experiencing the begining of the DSM curse. lol

Febo · 04-01-2006

Oh, god, you just dont even know.... may as well replace the upper and lower radiator hoses... and the radiator, you know, just as some preventative maitnence.

**Kracka** · 04-01-2006

The thermostat is a good place to start at least since its cheap, easy to do, and a wear item that needs periodic replacement anyway.

**LingLing** · 04-01-2006

Great, thanks for all your help guys. I'll report back when I get my FMIC piping worked out and such.

-Jason