T-stat problem (I think ) - Toyota Nation Forum : Toyota Car and Truck Forums

bowlofturtle · 02-02-2005, 04:34 PM

I'm having a minor issue with my car. I'll give you background info first off.

I got the raditor, cooling fan and thermostat all replaced when my radaitor blew in June 04. Since then no issues ever happened again. This is the first winter i had my car. After that work, my car hasn't been to the shop. Or had any problems well invovle the cooling system aleast. I did brakes and oil changes myself. My problem started to happen when the weather got colder. Plus i started to use 5w30 instead of 10w30. i dont think it matters. the issue happened about 4 days before i used 5w30.

Now here is the problem.

I hop in my car at 5am daily. Normally in chicago its about 15-35 degrees out side. When i hop in my car and start her up. My temp gauge goes to the middle. like normal operating temp. Instantly its very odd. That is my problem. While driving in traffic where i'm motionless. The temp gauge raises to JUST BEFORE THE RED hot mark and thats when the cooling fans kick in and it drops to normal which is the middle. Its all the same to me. but I get scared since its always up near hot. I get nervous everytime this happened. Doe it sound like a defective T-stat? It sounds like it working properly just opening late. I never had the issue in the summer. Just now i
n the winter. Its been doing it about 3 solid weeks now. at first i thought it was maybe frozen for a short while and it will cure itself but not i dont wanna drive the camry due to this.

Toysrme · 02-02-2005, 04:55 PM

Sounds like a thermostat problem to me. Either it's simply the wrong unit(opening at the improper time), or defective.

Either way... As long as you stay in the bracket of normal operating temperature, you're not going to cook anything. Idling in traffic always causes it to rise anyway. Heater core 'Esq designs are highly efficient cooling devices. They require only the faintest airflow to do the majority of the cooling they are capable of. However, 0 airflow They're fairly shitty. They heat soak fairly quickly and can't radiate heat fast enough.

Also is the fluid mix correct??? Yall didn't put in way too much A/F did you? (like dumping in straight fluid thinking it was a pre-mix, or exceeding 50/50 mix by more than 25%) The heat transferring ability of A/F is shit.

bowlofturtle · 02-02-2005, 07:52 PM

yea i'm targeting the t-stat as well.

actually now that you meantion the fluid. i have more info for you. 2 months ago before the weather got cold. i wanted to check up on all the fluids. So everything was good. i assume the shop gave me the 50/50 blend. Now i noticed the reserivor tank for the coolant looked just sewer shit has been in it. Was clean at one point. Now it was greyish. So i removed it cleaned it off. Put it back in. Then i refilled it eyeballing 50/50 bottle of water and some A/F it seemed like a 50/50 mix.

It was in the brackets but i really hate it going up to ALMOST RED. i had the car overheat once and i was scared as heck, i dont want it remotely close to RED. Any more ideas aside from doing a flush and changing the t-stat.

88 LE · 02-02-2005, 08:21 PM

Quote:

Originally Posted by bowlofturtle

Any more ideas aside from doing a flush and changing the t-stat.

I've had the same problem and it turned out to be a bad/stuck thermostat.

I replaced the thermostat + gasket and everything was fine. The parts were about $20 from a Toyota dealership.

So replace the thermostat + flush and go from there. If that doesn't fix the problem, you'll have to start looking into other parts of the cooling system.

bowlofturtle · 02-02-2005, 08:55 PM

possible that my t-stat is crap? it was just replaced in june

Which hose is it connected to on a gen3 i assume its the lower hose.

I've personally never done this task but i've seen it done on a 90's Mustang fox body. Looked simple enough with the whole coolant coming out and crap.

crah · 02-02-2005, 09:05 PM

Failing T-Stats are quite common. Most importantly, your temp gauge after the car is fully warmed up should be just under half. And that means always. If you are going near the red mark, you definitely have a problem. Narrow down your problems and you should have it fixed no problem. I would definitely check the fluid first and make sure you have the right mix and topped off in the radiator and the reservoir. Then I would check the thermostat. Now you mentioned that your car temp gauge jumps up to half right when you start it right? Does that mean within 5 seconds, 5 minutes, 10 minutes? If it jumps up that high right off the start, then it might me your coolant sensor. Even with a failing thermostat or blocked radiator, the car would have to get warm first before the temp gauge gets that high.

bowlofturtle · 02-02-2005, 09:15 PM

it takes zero seconds for it to go the middle (warm) on start up because once i put it the on postion its up in the middle before i even crack it.

My question would be if its a stuck t-stat. lets say stuck open, that would mean its letting coolant flow thru the block too early, that also would mean long ass warm ups.

If my t-stat is stuck closed that would mean no coolant is flowing to the block meaning it should warm up like normal and then overheat.

I dont have any of those issues, therefore i dont consider really a t-stat. I mean yea trial and error is the best way but i don't think this would be one that would make sense. I dont have a block radiator either. The Coolant sensor is one to think about. but why would the coolant sensor read warm coolant on cold ass warm ups.

Maybe this info would help. 5am my car sits there over 8 hours. I put the car in on postion but didn't crank it yet. Coolant sensor reads middle already. Reguardless if it sat there for 8 hours or 48 hours.

Toysrme · 02-02-2005, 09:31 PM

Quote:

it takes zero seconds for it to go the middle (warm) on start up because once i put it the on postion its up in the middle before i even crack it.

That is simply wrong...
Even in a warm garage with a block heater, you couldn't heat the coolant that fast.

Take your Haynes and check the coolant temperature sensor.

bowlofturtle · 02-02-2005, 09:38 PM

Quote:

Originally Posted by Toysrme

That is simply wrong...
Even in a warm garage with a block heater, you couldn't heat the coolant that fast.

Take your Haynes and check the coolant temperature sensor.

tell me about it. Just in the ON postion its warm already.

I dont have a manual

is this something hard to change up or get to.

karugs · 02-02-2005, 10:47 PM

It could also be a thermostat installed the wrong way.

You mentioned that the stuff in the coolant reservoir became dark like sewer crud, could it be oil? I'm just speculating since your problem is heat-related, and that you ran the car at near the red mark for some time. Coolant could be getting into the oil or vice versa.

I hope it's not the second one, check your thermostat first. Yes I know it's freakin' cold but if I were you I'd rather get out there in the cold garage/driveway and check your thermostat than be stuck in the cold miles from home.

bowlofturtle · 02-02-2005, 10:53 PM

well the t-stat was on there since June 04. I didn't have any overheating problems period after that. Then i saw this issue happening 2 weeks ago.

THe stuff in the coolant looks more just dirt and junk like that. Not really like oil. It might be i really dont know. I guess i'll just grab a T-stat for now. since its the cheapest attmept. Just to confirm it is on the lower raditor hose. On the end towards the block right?

Normally what is your resevior tank suppose to look? Mines was never as green and as clear as the stuff in the radiator. The stuff in the radiator freaking clean as can be from what i can see. And its very toped off.

Where is my coolant sensor? Someone help me out with a diagram or something?

88 LE · 02-03-2005, 12:48 AM

Quote:

Originally Posted by bowlofturtle

Just to confirm it is on the lower raditor hose. On the end towards the block right?

Correct.

Heres somes pictures of it from my 3S-FE. Its the same for a 5S-FE.

Quote:

Where is my coolant sensor? Someone help me out with a diagram or something?

Its (ECT (engine coolant temp)) on the neck that bolts to the right side of the cylinder head. The upper radiator hose is connected to it.

Yours will look a little different then mine (from a 3S-FE).

Repair and troubleshooting info:

ECT
-------

http://www.autozone.com/servlet/UiBr...3d8013e283.jsp

Thermostat
----------------

http://www.autozone.com/servlet/UiBr...3d8013e98f.jsp

bowlofturtle · 02-03-2005, 02:04 PM

thanks 88 . i found both of them pretty nicely.

I got the specs from all-data today. And morrow i shall be testing out the ECT with my DVM and possibly changing my t-stat

This might not be big factor but i recalled around the same time i had this issue i went on a mini drifting day. Not really drifting but sliding. And i hit the curb hard. Front driver wheel banged up and hub cap cracked and flew off. Steelie was minorly damaged. Would that cause something like t-stat to move or something??

88LE can you give me a detailed list of the problems you experienceds?

88 LE · 02-03-2005, 05:24 PM

Quote:

Originally Posted by bowlofturtle

Would that cause something like t-stat to move or something??

No.

However running into curbs is not good.

Quote:

88LE can you give me a detailed list of the problems you experienceds?

My problem was that the temp gauge would fluctuate up and down as I'm driving.

The needle would be in middle (normal operating temp) and almost go up into the red. Then it would go back down to the middle and repeat the process. It was all random though.

First thing I suspected was a stuck/malfunctioning thermostat.

bowlofturtle · 02-03-2005, 08:57 PM

mines isnt really fluctuating like yours. It does it but its more controled. It goes up and fans kick in then goes back down.

But you didn't have my startup issue did you?

Hopefully my test works out well and i can pin pount what it is and why is it. Good thing is i have people to guide me.