tt4wd runs to cool

[gotama]

i put a new rad in from rock auto..sweet deal..but now it runs to cool..i put a 180f thermostat in and now a 190f..around town its ok but soon as im flying down the hwy it cools off and starts to miss ,,my toy likes to run hot..midway on the gauge..i had to block over half the rad to get it perfect..also in the morning takes like 15 mins at 70f to warm up!!..anyways any suggestion wud be appreciated...thanks!

[Petros]

a properly working thermostat is supposed to maintain a constant temperature, no matter how large the radiator. it regulates the temp by controlling the flow through it. It is not just an on/off switch. do you buy quality thermostats? not the cheap ones made in communist factories in the orient. good ones are in the $14 to $19 range in cost, cheap ones are like $5.99 and not worth owning, many are junk out of the box, or will fail too soon and your risk heavy engine damage when it does.

you can buy 190 deg t-stats, but that is higher than the factory spec. the temp gauge should stabilize just below half way. On long climbs in hot weather it may move to just above half way. and it should always stay withing this range during normal driving.

check over your whole cooling system, including the sensor and gauge, to make sure it is not something else. the simplest way to verify if you sender and gauge are accurate you can buy an after market temp gauge and install it and compare running temp, warm up time, etc. They do not cost very much.

All of the Tercels I own when running properly operate this way with the temp staying in the middle 20% of the gauge range.

[gotama]

they were both "stant" ..cheap??

[gotama]

the gauge is fine..moment it goes over halfway mark fan comes on and gauge drops down..and i got good heat coming from the heater..when it on the hwy going 70 mph it drops to around a 1/4 mark and runs like crap and blows cold air on the heater..ill look for the most expensive thermostat i can find when im back home..thanks petros

[Petros]

the Stant brand used to be US made, who knows these days however. the best t-stat would be from the toyota dealership. I think both NAPA and Autozone sell a lifetime guaranty premium t-stat you might look into if there are no dealers nearby.

[ARCHINSTL]

I've used both Stant and the Toy brand in the past and just now a FailSafe (the latter was all I could find at AZ: ADV, O'R, or any Toy dealers in STL did not have anything in stock for a T4WD and I needed it now)! We shall see, as I was hesitant, given opinions here over the years, but I needed it NOW!
The AZ "premium" brand, #15758DLG, is not stocked in any STL stores. Ditto with any of the NAPA stores (including one at $33 ).

My history on tstats - all were 180º:
05/2005 - ? brand from AZ on buying Goldie - cost was $12
11/2008 - Toy brand from dealer - $18
06/2014 - Stant Super Stat #45758 from ADV $10. No prob, but removed the radiator to do vinegar flush, so it seemed prudent
06/2016 - Ditto as above, same price and vendor. No prob, but removed the radiator doing t-belt, so it seemed prudent.
01/2019 - FailSafe #7214 $14 from AZ. Needed, as above stuck open in Winter!
Tom M.

P.S. Look for my report on 8%#@*! replacing the t-stat outlet and hoses a few weeks ago

[Petros]

likely you will have to order ahead any of the premium thermostats for a car this old.

one time I had one start to give me trouble with slowly increasing set point (it was about 4 years old so about time for a replacement). I went to I think Autozone, all they had was communist made thermostat in stock the Tercel atr $6. I bought it and installed, temp returned to normal. But perhaps 7 months later the temp was fluctuating while steady state driving, drift up and down on the gauge, each day the temp swing was a bit more. I figured the thermostat should not be bad already, but either my gauge was going out, or the "new" thermostat was already getting marginal (remembering it is was a cheap one). I bought a quality US made thermostat and installed it, temperature fluctuations went away.

Not worth risking your engine on a Chinese made thermostat. Some are junk right out of the box, and even if it outlasts the 30 day warranty, not worth the trouble of having to replace it at less than a year.

[The Professor]

the Stant brand used to be US made, who knows these days however.

Just bought a Stant radiator cap, lifetime warranty, but made in Mexico... On RockAuto it had the same part number and photos as the Gates (I think it was Gates) cap, but that brand only had a 30-day warranty.

[irowiki]

Kinda sounds like both your thermostats are junk and stuck open.

[splatterdog]

Kuzeh is the OE stat supplier.

[ARCHINSTL]

splatterdog mentioned Kuzeh as OE t-stat supplier, so I checked Amazon:
https://www.amazon.com/Kuzeh-W0133-1635 ... automotive
And ADV:
https://shop.advanceautoparts.com/p/kuz ... lsrc=aw.ds

Tom M.

[Petros]

Kuzeh is the OE stat supplier.

I did not know that, thought it would be an Asisin. Advance Auto sells the Kuzeh with a one year warranty for the Tercel for $23.

https://shop.advanceautoparts.com/p/kuz ... lsrc=aw.ds

[teranfirbt]

I never trust anything but OEM T-stats and radiator caps anymore. I bought a Stant that had a weak spring, so at lower engine speed it would be fine, but once you got on the highway the water pump would build enough pressure to force the stat open and it would run cold. I chucked that in the trash and got an... AC Delco? I can't remember, but it was worse, it would only hold closed below about 2000 RPM. I chucked that in the trash as well and bought an OEM stat and have had zero problems since.

[Petros]

I had a recent experiance, it just arrive today in fact from Rockauto.

I needed a new water pump and thought I should change the t-stat while I am at it. I order a Gates water pump (a US company) and a Gates thermostat. Rock auto also had the Aisin thermostat for about $5 more, so I bought one just to get a look at it.

The water pump arrive, it looks good, in the Gates box. but the plastic bag the pump was in inside the box said "made in China". The Gates thermostat says "made in USA", and looked similar to other t-stats I have used. the Aisin thermostat was made in Japan, and it really looks like a robust piece of equipment, heavier, uses a rubber seal on the valve, robust construction, high quality surface finish on the parts, it looks like stainless steel, heavier spring too.

I am not sure what to do with the water pump. fortunately they are not too hard to replace so I might just use it and return the 4 year old one in it to NAPA for a replacement (supposedly lifetime guarantee, we will see). That way I will have a spare one, if they honor their guarantee.

[Mark]

I've bought several thermostats over the years. I've learned to ignore the name brand on the box and look at the name brand on the thermostat itself. It seems that the brand name on the box and the brand name on the thermostat hardly ever match.