6G Celicas Forums

We'll i just picked up a 170 Degree low temp. thermostat for my 3s. I was wondering if anyone else was using one and how they liked it. I bought the Gates 170 Degree Thermostat, looks like a quality thermostat, hopefully i can put it in tomorrow, but i wanted to post up on here first and see who was using one and how they liked it. not just the 3sgte but the 5s, 7a, any motor.

I used to have one in my 5s, the engine ran a little cool most of the day then would run very very cool in the mornings on the freeway, then I was telling my boss (a former NHRA pitcrew mechanic) about how much I liked it and how cool my engine was running. He said that it isn't good to have the engine run as cold as mine was running in the mornings, the gasoline needs to be a certain temperature to explode efficiently, the cooler it is the harder it is for the gas to vaporize, in carb'd cars it's more of a problem because there is nothing to spray the gas into a mist, so with our cars the injectors help, but injectors don't vaporize the gas as well when they are cool compared to when they are hot. So the gas mileage could go down a little bit if it runs excessively cool. I tried searching everywhere for some kind of documentation that tells the perfect temperature for gasoline to explode, I can't find anything, the only thing I found a lot of was how gas doesn't vaporize well when it's cool. So I can't tell you if a 170 degree thermo is bad, when compared to a 180. I've heard the 3sgte naturally runs hotter than other engines, so if you're running a little hot then I would put one in. But if yours runs as cold as mine was in the mornings (needle was 1/4 of the way from Cold) then I would put the stock one back in.

3S does run a little hotter, i have a 72 deg.C in my 7th gen and it runs at 72 on the Power FC commander. what the NHRA mechanic said is true but the 10 degree difference wont matter.

What he was referring to was how cold I said mine was running in the mornings, it would run like I didn't even have a thermostat until it got hotter later in the day. I wish I had an actual "temperature gauge" instead of a gauge that said "H" and "C" that way I could say the temperature in the mornings, it was almost at C it was so cold, and it stayed there until I sat in traffic or if it was a hot day.

This post has been edited by match220: Aug 25, 2009 - 9:09 PM

with just a C and a H you cant accuratly tell how hot the engine is so no point in going off that.

im running a TRD 77 deg one and its brilliant, sits on 77 solid on the highway.. Especially good for these hot little 3s'

right, but I knew my car before the low threshold thermostat, and the gauge always sat in the middle of C and H, then when I put the low threshold thermo in it would run a little cooler in the day time and in the mornings it would be abnormally cold 30 minutes after running. that's all I was saying.

i'm running no thermostat. won't work on my setup.
170 and up is fine for the 3s depending on where your sensor is.

Ahhh thats why my gauge sits a little lower always wondered why

well k i guess i have a lower temp thermo

Just picked that in one of my old threads:

The TRD thermostat lower engine temp by 20degreesF and transfer the temp into the radiator. This has the effect to cancel a little the fact that this is reducing engine bay heat, because the hot air draws back into the engine bay, but it is not a major problem, or major cause why the intake is so hot on the 3sgte (I have a power fc to monitor it).
The more important point is that reduce conduction and radiant heat on cold intercooler pipe and intake manifold, so it DOES reduce intake manifold air temperature which the primary heat source is metal to metal contact with the engine...
it doesn't reduce engine bay convection heat (average temperature ambient air in engine isn't lower)
it improve heat absorbtion into the combustion chamber because of the greater difference of temps between hot gases and coolant
it also improve conduction heat transfer between turbine and coolant, which is very good for a ceramic turbine...

why? if your engine is running too hot on your setup, then try adding an oil cooler, if you already have one, try to find a better one or relocate the one you have. There is a reason cars have a thermostat, I've never considered running without one. And I don't consider it an option if the engine is running too hot unless there is no other option.

you could also drill a 1/32 hole in your stock thermostat, its way better than running no thermostat at all

i have a very modified setup. don't worry about my special needs for my motor. i'm not quite sure why i typed that in there. at any rate 170F and up is fine for the 3s motors.

I was used a TRD low temp thermostat (I think 72C) in north Greece on 3sgte engine. The engine temperature at the commander was 80 – 84C.
Now I have changed it with a stock (genuine) one to try it. The engines temp is 88 – 92C.
So I will change the stock thermostat again with the TRD.

the only problem is that with the stock ECU fuel map, there is a fuel correction of about 10% between
50 and 80 degrees C of water temperature

so think of a standalone if you want to run colder than 80 degrees

I´m using the C-one 69degees C, thermostat on my celica st205 and it is very good. the good side of colder thermostats is that, the local boilings that i belive caus alot of 3s-gte block cracks is not that close.
Beqaus you run the engine coolder you have alot more room for the heat to rise some befour it gets to dangures levels.
But this is just my opinion.
But i cannot se why so many manufactures have them if they dont work....

has anyone using a colder thermostat seen a drop in their needle between hot and cold? i put the thermostat in and i guess 20 degrees will not make that much of a difference but i thought the needle would drop a little bit.....20 degrees as in F..i have seen no change in where my needle sits, still at the same spot as with the stock one in. Now its not reading in degress i know that, so maybe its just the stock gaugle cluster..i guess if i put a temp gauge on it i would see a difference

it makes a difference, the C point on the needle is about 50F and the middle is 92F
so between 84 and 74 (TRD thermostat effect on my car) i saw the difference on the needle

I don't know the exact number of our stock gauge cluster, but I think you might mean 192F not 92F.
The middle point on our gauge cluster has a big give and take difference. This is done so that the customer wont run back to the dealership when he saw his needled slightly higher than the day before with the changes in weather. You would really need an after market gauge to see the actual temperature difference.

Some car manufactures do things differently and actually do provide and accurate gauge. I've driven a new GM car that did that, and it still had a big zone marked off in the middle to show you whats considered acceptable, but our cars dont do that.

That was in celsius, and I HAVE an aftermarket temp gauge (POWER FC)
the needle drop 1/4inches between stock thermostat and TRD thermostat (10degrees drop) and it's easy to see

This post has been edited by domyz: Sep 20, 2009 - 9:23 AM

st185's run at 190F...i have a 170F thermo. i have seen no change...where did you get your TRD thermostat at? because i couldnt find one