Thermostat Jiggle Valve on 3.4L 6 Cyl TRD

After replacing the thermostat I was browsing through my repair manual and noticed that the jiggle valve must be up plus-or-minus 15 degrees. I don't recall in which position I installed the thermostat.

How important is the location of the jiggle valve and if it is not up what will happen?

 

If air is not bled from system it can overheat. Purpose of jiggle valve is to bleed system of air without having to do it manually.

 

I'm getting a little tired of posting this, so for one last time.
The Toyota FSM gives that spec for the 4 cyls and "down" (6:00) for the 3.4.
It is has been widely documented on this and many other forums that placing it "up" on the 3.4 results in about a 10* increase in the ECT sensor reading.
Read this entire thread before commenting. http://www.yotatech.com/f2/5vz-fe-r...ing-belt-pictures-pleasure-249481/index2.html

FSM for the 3.4

 

I was actually just wondering this the other day... You da man

 

10-13 degree difference in temps is what I got.

 

When I removed the thermostat, the jiggle pin was at the 12 o'clock position and when I installed the new thermostat I placed the jiggle pin at the 12 o'clock position.

I bought the truck brand new in January of 1998, BTW.

 

I just replaced rad hoses and thermostat. I was confused after reading in my Haynes manual that it should be at 12 o'clock. Mine was coincidentally came out with it at 7 o'clock. I was confused as I'm the original owner and it's other original thermostat, so I searched here. I trust y'all and the FSM that was referenced so, I put it at 6. Strange about the typo in the Haynes though been using those for 20 years...

 

I just picked up a Gates 170 degree thermostat to replace mine and it doesn't have a jiggle valve. Do you guys think this will lead to problems?

If so, does anyone have a part number for a toyota 170 degree thermostat for the 3.4?

 

Does it have a little "bite" out of the outer circumference? If so, put it in with the bite at 6 o'clock. Or, pays your money at the dealer.

 

PN

$29 90916-03075 Thermostat

90916-03075

Toyota part.

 

I know it's an old thread, but I just went through this, not enough definitive info on it at one place, the jiggle pin goes at the top for the 4 cyl. engine and at the bottom for the 6 cyl. engine. in the Tacoma. So that is why the confusion exists, too many folks comment without telling their engine size and it's very confusing. And don't stress about torque for the bolt and two nuts, you can't get most torque wrenches in there, it's a job for a stubbie ratchet for sure. but it would be about 6 ft pounds if you did, very little force needed, just tighten up and stop. if you drop one of the nuts you might add an hour to the process, took me two hours total. if the tstat was clogged with rubber pieces, someone probably used USA antifreeze marked, use in ALL cars. it has stuff that will destroy Japanese components, always use the Japanese stuff, it's a delayed damage and nobody gets it. and a year after someone changed the anti freeze good luck convincing them they used the bad stuff and now owe you repairs. the bypass line had to be replaced also, due to the same issue.