Thermostat replacement / jiggle valve should go up or down??

Thermostat replacement / jiggle valve should go up or down??

 

Thank you!!

does it make any difference?!

 

I got a code p0168 that’s why I’m replacing it, should I replace the temperature sensor as well??

 

yeah that's a fuel temp code, I don't think it has anything to do with the thermostat but I could be wrong. Quick google search says to suspect the fuel sensor, wiring or IAT sensor to name a few.

 

2.4 & 2.7 = Up (+ or - 15)
3.4 = Down (+ or - 15)

 

Replaced the thermostat but the temperature goes up within 5 minutes on

 

This is the old one

 

Not true. My buddy wanted to test the theory if it will make a difference if the jiggle valve is at the 12 or 6 o'clock position. Drove it around for a couple of days at 12 and changed it to 6 o'clock and temp remained the same on his scan gauge at both position.

 

P0168 is the fuel temperature too high.

https://partsavatar.ca/p0168-obd-ii...high-solution-pcm-fuel-temperature-iat-sensor

 

I had the thermostat replaced when the timing belt and all other stuff in that area was replaces. They put the jiggle valve up and my running temp went up 10 degrees.

When Toyota replaced my frame, I asked the mechanic to check.the t-stat and put the jiggle valve down. Running temp dropped 10 degrees.

That was per my Ultragauge...

 

That jiggle valve should always be at 12 o'clock, any air that enters the system during replacement needs to escape to the radiator somehow....there are probably engine designs/thermostat locations that it might make less difference to cooling system function than others, but generally it's a rule of thumb that a mechanic should know. A simple Google will tell you it's function and clock position.

 

Mine doesn't even have one and it's been fine for years.

 

It's likely not because of position but that the second mechanic bleed the system more thoroughly than the first. All the valve does is let's trapped air pass through to the radiator. But think about it... When the thermostat opens the air will pass through anyway which is why some people say up, some day down and it seems according to people's experience it doesn't matter. Mine doesn't even have a jiggle valve and it's been just dandy for years.

 

Originally the factory service manual stated to put the jiggle valve on top in the 12 o'clock position. Toyota later sent out an update for the FSM that stated the bleeder valve for the thermostat of the 3.4L should be placed in the 6 o'clock position.

Nope...system was bled perfectly both times. The first time was by a good friend of mine who does mechanic work on the side and he is very meticulous. The second time was by my local dealership during my frame replacement, and they were gracious enough to let me look things over throughout the entire process, which was really cool.

 

Code is p0128

 

https://www.engine-codes.com/p0128_toyota.html

 

No shit, didn't know that! I appreciate your correction, I did some searching and was unable to find out the "why" but you're definitely right. If you have any more info about why they switched it (problems with air behind the thermostat or for cooling issues) I'd appreciate you sharing.

 

No problem

I agree with you, as everything I was ever taught said bleeder valve in the 12 position, and I think that stands true when the t-stat is on top of an engine. I think the difference is, and this is my own observation, since the t-stat of the 3.4 is lower on the engine, as you fill the radiator with coolant, it bleeds through from the lower hose to the engine. Essentially back filling into the motor and pushing air up through the engine.

Other than that, I have never found an explanation. The Toyota engineers found some reason to change it.

 

I was curious about the downward jiggle valve as well. I verified in the FSM that it is indeed installed downward (b).