Strange Temperature Behaviours

[corollarv]

Hi everyone,

My names Luke, i own a 94' Toyota Corolla RV Seca 1.8 Twin Cam EFI, it's auto. I'll describe the issue i'm having as best as possible.

When i start my car, and leave it to warm up, the temperature will get to operating temp fine, but as soon as i start driving at a constant speed, on local roads with minimal stopping, the temperature of the car drops right down to below cold and idles high and is choppy (as all older cars are when cold).

The mornings i do not let my car warm up, and just drive, it doesn't get to operating temperature at all until i stop at traffic lights (which is rare on the first 20 minutes of my trips in the morning), and it takes a long time for the car to drop into 4th gear.

Say i leave home and get onto the motorway when its cold out in the morning, its quite annoying driving on the motorway in 3rd gear with no O/D at 110km/h.

and the fact the heater isnt very good in the morning pains me.

I read another forum and it suggested by other peoples problems this may be my thermostat, i can't tell you the last time it was replaced.

When started cold, and i do city driving which is start stop start stop, the temperature gauge goes up, then down, up, then down... it's quite annoying watching my idle change so much, i've gotten into the habit of dropping the car into neutral when stopped at traffic lights so it can warm up for taking off.

I'd appreiate all the help i can get on this one guys

[Bitter]

thermostat, start there.

[Kiwi-Corolla]

Hey Luke, welcome to Toyota Nation. Definitely start by replacing the thermostat. It's a very inexpensive part to replace and will more than likely solve your problem. Just make sure that the jiggle pin on the new thermostat is in the 12 o'clock position when you install it

[corollarv]

Originally Posted by Kiwi-Corolla

Hey Luke, welcome to Toyota Nation. Definitely start by replacing the thermostat. It's a very inexpensive part to replace and will more than likely solve your problem. Just make sure that the jiggle pin on the new thermostat is in the 12 o'clock position when you install it

Thanks I will try and get this replaced on the weekend! I definately won't be doing it myself, I will be taking it to a mechanic to be done.

If the problem is still there i'll repost,
Cheers!

[mvftw]

Luke, thermostat would be correct, but also replace the upper & lower rad. hoses while you have the anti-freeze out...

[miib14]

hi and welcome mate, as said by the other members try the thermostat first..
afew people i know have had this problem and it was the thermostat...

[blumonster]

I have a similar problem. My heater works well but the temperature gauge never reaches the middle. Always lower and during 25 miles freeway driving it drops to a quarter level, sometimes even lower than that.Only after coming to a stop and idling for a while it goes back to a 2/3 or a tad below half on the gauge.

I have been using Castrol Syntec 0W-30 now and synthetic oil for 3 years. The ambient temperature during my ride is within 35-50 degrees F./ 0-10 degrees C. I had a radiator flush done 2 years ago, and timing belt and water pump replaced 1 1/2 years ago.

I might be wrong but I noticed the remp gauge started being lower than half after radiator flush. It used to be almost at half. It might just be a coincidence.

What do you think? Do I have a problem with the thermostat too?

[Bitter]

replace thermostat.

[1jzdreamer]

8-12 bucks for a thermostat and gasket.

oe is about 25-30 at the dealer. Either way an easy fix.

Listen to Bitter.

[speedy25]

If you have any doubts put the thermostat in a pot of boiling water. There you can see it open and close, or not! usually low temp problems are caused by a partially open or fully open thermostat that stays in that position. Overheating by one that doesnt open or partially opens.

Todays thermostats arent very good quality and are DEFINITELY a replacement item that you might need a few over the lifetime of the car.

-SP