Temp gauge going funky, Updated! Changed Thermostat but still does the same prob Options

[reko]

As i was driving on the highway on friday night i noticed that my temp gauge was almost at cold which isnt normal for a sunny summer day.

After rolling for 10mins, it went to normal temp. but started to go slowly from normal to cold back and forth 4 to 5 times after what it stays at the first 1/4.

It did it only once, but then on the next day, it did it 2 times and went back to normal.

Nothing happened yesterday, but still, i dont really like this.

I'm thinking thermostat, but who knows?

Is it bad? I mean I went to school today (which is about 20kms from my house)... should I change that tonight?

**UPDATE**
25/08/08: Changed changed the thermostat... The shaft bent so it was stuck open so I just put one for Camry since the one for Celica 2.2L didnt fit (dont know why but anyway....) Still does the same problem as before... temp gauge isnt stable...

So what's next?
Water pump maybe

This post has been edited by reko: Aug 25, 2008 - 5:47 PM

[Remy]

Yep sounds like a thermostat going bad replace it.

[reko]

Is it dangerous? I mean... can it wait for 2 weeks?

[parriehunter]

you would probably want to get it done asap, they aint hard to replace. when i did mine i didnt even drain all the coolant just a little bit so when i un did the housing heaps of coolant didnt go ever where. half hour job.

Mine was doing the same thing when it went.

[Remy]

As long as the thermostat is not stuck in the closed position as it could cause your motor to overheat therefore it could kill your motor causing a blown headgasket, if its stuck in the open position kinda like what you explain (the temp drops) you will be using more fuel to keep the engine in normal operating temps my advice is to change it as soon as possible but as long as your thermostat is not stuck in the closed position you should be able to drive it for awhile you'll just have a lower mpg.

[GriffGirl]

If you absolutely MUST wait two weeks, you could try removing your thermostat and boiling it in hot water. I've heard this will help unstick it. This shouldn't substitute for replacing it though.

[Batman722]

it's the thermostat stuck open. Cooler coolant is continuing to circulate through the system cooling the engine more than what is should be. It's a bad thing if the stat was stuck closed and there was no circulation and things get real hot real quick.

That's "OK" and doesn't NEED to be changed asap. You could wait a few weeks if need be.

[reko]

it's the thermostat stuck open. Cooler coolant is continuing to circulate through the system cooling the engine more than what is should be. It's a bad thing if the stat was stuck closed and there was no circulation and things get real hot real quick.

That's "OK" and doesn't NEED to be changed asap. You could wait a few weeks if need be.

All good.

It still doing it... temp gauge stays between first 1/4 and normal temp... depens on if I'm on the highway, in traffik or just hitting the streets.

I'll stop by to auto-part after school.

Anyone knows if i can buy the one for the Camry since its the same motor? Because usually they dont hold celica parts... but they do for Camry (I know, it's dumb!)

This post has been edited by reko: Aug 20, 2008 - 9:14 AM

[rjbibeau]

same part number they will be the same thing.

[reko]

$31 tx included with the gasket at auto parts.

Just to be sure, is it located at the botom of the radiator or is it at the end of that hose that goes from the rad and stops halfway through the head where the clamp is?

I'll try to take pics and create a DIY

This post has been edited by reko: Aug 22, 2008 - 9:12 AM

[reko]

All right just changed the thermostat...

The shaft bent so it was stuck open

I just put one for Camry since the one for Celica 2.2L didnt fit (dont know why but anyway....)

Still do the same problem as before... temp gauge isnt stable...

So what's next?
Water pump maybe

[reko]

as i was going to school temp got really hot... almost in the red zone (I'd say it was missing 1/8 inch) so i turned my heater on and it went back to really cold (below first 1/4).

When i came back, i didnt put the heater on and it stayed in the first 1/4

I dont have school tomorrow so it would be the best time to fix this. Any ideas? Could it be the fact that its the thermostat for a Camry and its not the same size has the one for the celica the dude sold me at first??

I forgot to mention that im at 195 000 kms so that means timing belt and water pump in 5000 kms

This post has been edited by reko: Aug 25, 2008 - 5:45 PM

[reko]

I realised yesterday that i hear a weird noise comming out the water pump ... could it be a defect thermostat (even if i just changed it) or is it really the water pump?

My engine keeps on overcooling....

[Dr_Tweak]

If it's still getting too cool then there's still a problem with the thermostat, you need to make sure that it fits perfectly in the housing and also make sure you replace the rubber gasket that goes around it.

For what it's worth, NAPA seems to have the wrong part listed for the '94 GT, I know that I recently dealt with that and they kept giving me the wrong one, I asked for one for a '96 I think and that was the right one.

Hope that helps!

-Doc

[reko]

If it's still getting too cool then there's still a problem with the thermostat, you need to make sure that it fits perfectly in the housing and also make sure you replace the rubber gasket that goes around it.

For what it's worth, NAPA seems to have the wrong part listed for the '94 GT, I know that I recently dealt with that and they kept giving me the wrong one, I asked for one for a '96 I think and that was the right one.

Hope that helps!

-Doc

That's what happened so i just took the one for Camry's since they are the same engine and it fit perfectly...
The guy had on ly 94-95 in his book so...

Anyway yeah i changed the gasket as well... might only be the fitting part maybe...

Is there a way to put the thermostat i mean... is there a "top" and "bottom" part? Maybe i put it upside down.

The one i had that was broken has a little bleed valve (hole) in it and not the new one, think it cuold result in some issues?

[Remy]

Its only like $12 from dealer for a oem thermostat and make sure its aligned properly, their is a certain way its suppose to be installed. Make sure the jiggle valve is aligned correctly. I don't have a picture to show you sorry.

[Havok1997GT]

First off, its always best to go with the Dealer on parts like this. It may be more pricy, but you know your getting the right part brand new. Also makes it far less likely that the part is defective. Still possible, but unlikely.

Second,(and if im missing a part,step, or im just plain wrong about how this whole things works, please correct me.) the water pump just pumps the water, the thermostat is what regulates how much water it pumps. It reads the Temp of the engine, and cools as needed to keep the engine at normal Temp. Typically, with a bad water pump, its just not pumping to cool the engine, thus the engine over heats. If its running to cold its one of two things:

1, your thermostat is not working right
2, your gauge is broken

There really isnt anything other then that that could be causing a over cooling issue.

Again, this is my understanding. I havnt had to deal with many over cooling issues, lots of over heating issues, but not a lot of over cooling. But that is what you should be looking at as far as i know.

[reko]

Its only like $12 from dealer for a oem thermostat and make sure its aligned properly, their is a certain way its suppose to be installed. Make sure the jiggle valve is aligned correctly. I don't have a picture to show you sorry.

There isnt a jiggle valve on my new thermostat

and how is it supposed to be aligned???

[GriffGirl]

I have to disagree about going with the dealership on this one. I really think a NAPA or whatever thermostat is just fine, as long as it's the correct part. I have one from like Autozone or Schuck's that works just fine.

IIRC the thermostat can really only go in one way, it won't fit if you put it in "backwards". Yes, make sure you replace the gasket. (sounds like you did) Check your coolant level - if you're low, you could overheat. Run the car for a few minutes with the radiator cap off to get excess air out of the radiator. Did you replace your radiator cap? If your cap is old and doesn't hold pressure, you'll overheat there too. Replace your cap.

If after doing this it's still acting up, try replacing the coolant temperature sensor (located on the engine block, should be just below the thermostat if it's the same on a 5s as a 7a). This should run you about $21 at NAPA or Autozone or whatever you guys have up there. One of these things should fix it - if not, it's time to explore other options like water pump or heater core. But rule out the easy stuff first.

[reko]

IIRC the thermostat can really only go in one way, it won't fit if you put it in "backwards". Yes, make sure you replace the gasket. (sounds like you did) Check your coolant level - if you're low, you could overheat. Run the car for a few minutes with the radiator cap off to get excess air out of the radiator. Did you replace your radiator cap? If your cap is old and doesn't hold pressure, you'll overheat there too. Replace your cap.

If after doing this it's still acting up, try replacing the coolant temperature sensor (located on the engine block, should be just below the thermostat if it's the same on a 5s as a 7a). This should run you about $21 at NAPA or Autozone or whatever you guys have up there. One of these things should fix it - if not, it's time to explore other options like water pump or heater core. But rule out the easy stuff first.

No the thermostat is not backward, when i said which way it goes i was talking of that little bar in the middle, should it go like this: l or like this -

Also, the main problem is not overheating, its overcooling...

I'll try to remove the rad cap and maybe change it with the one i have on my other radiator. Also, i also read about the coolant temperature sensor... I found it on my car and i'll try the trick with the ohms