I'm installing the 170 deg thermostat that came with my URD fuel kit and I notice that it doesn't have a jiggle valve. Isn't a jiggle valve important? Should I drill a small hole in the flange?

 

I've always thought so, and the mechanic I did my timing belt with thought so when I pulled a new thermostat out of a box and it didn't have one (so we didn't put it in).

Some random words about on the pin:
http://www.are.com.au/feat/techt/thermostat.htm
http://www.arrowheadradiator.com/pre...m_failures.htm

 

Good links Mark, thanks. Were you able to find a 170 deg thermostat that has a jiggle valve or are you running the stock Tstat?

 

Great question and great links.
I've had the same questions since I purchased my Napa 170 degree thermostat.

 

Funny this came up just a week or so after I did my thermostat. When I pulled out the thermostat and it had no jiggle pin I wasn't sure what to think. Looking back on it, a 1/8" hole might be a good solution. As it was, I installed as'-is (With no jiggle pin).

EDIT - anyone have a comparison - say the 160F TRD thermostat?

further edit - interesting note. Instructions say to put the jiggle pin at 12:00. I pulled my and found it at 6o'clock (factory).

 

I agree, it will not hurt anything to put in a 1/8" hole in there

 

I never looked for another one. The one that's in there is (I think) a 180 which is stock (right?). I should probably add that to my list of things to do.


Yeup... all the instructions I've ever seen says that the pin/hole needs to be at the top. I'm not sure of the physics, maybe just to stay out of any sort of sediment? But then I can't imagine that being an issue in a cooling system like this.

 

Yeah my factory jiggle valve was between 5 and 6 o-clock. I took a pic before I removed it.

 

My 2001 FSM says to install the T-stat on the 5VZFE "with the jiggle valve downward".

 

hmmm... WEEEEEEEEE!!!

http://aarc.epnet.com/application/9316/9316.htm
- "Engine and Engine Overhaul"
- "Engine Mechanical"
- "Thermostat"
- "Removal and installation"
- Fig 8: "If so equipped, the thermostat must be installed with the jiggle valve at the top".
- Also, point 4 in the text. "Some thermostats use a jiggle valve that must be installed at the top or 12 0'clock position"

 

i used the trd one, it had a jiggle thing

 

Was it 170 deg?

 

As well my 96 FSM states that the jiggle valve 5VZE is in the 6 oclock position . Interesting enough the 3.0 is supposed to be at the 12:00 position.
I think the TRD thermostat is 160 degrees.

 

Gadget replied to my e-mail so I thought I would pass the info along. He said hundreds of people have installed the thermostat "without any issues at all" and "there is no reason to believe you will have a problem with it. You can drill a hole in it if you want, but it is not necessary."

 

Well, the general consensus of the rest of the 'net is that having the hole there is a good idea.

It's of course your decision on the information source you'd like to follow, but I know which way I'd go.

 

Yeah I'm going to drill a small hole in it if I can't find one with a valve already. But then who do I believe about the hole being up or down, LOL.

Anyone know for sure what temp the TRD T-stat opens at?

 

The sole purpose of the "jiggle" valve is to help drain the block when you drain the coolant.

Without it, it will take a little longer to drain the block. That is it.

Gadget

 

Now that would explain the downward position, if you believe the valve should be downward.

 

I usually pull my thermostat anyway when I drain the block during a coolant flush. I am surprised at some sources stating the jiggle valve being down because airlocking can be a pretty serious condition on some vehicles. I am not sure I totally agree with Gadget on the fact it is for block drainage only in all cases, but I think it is safe to say that as long as you had a jiggle valve or have put a small hole in there for air relief/coolant drainage then you should be fine. I have mine in at 12 o'clock, but I see that the FSM has it in at 6 o'clock on the 5VZ-FE yet they call out within 15 degrees of 12 o'clock on the 2RZ-FE and 3RZ-FE.

Only thing I can come up with is that the thermostat is located down low on the 5VZ-FE (it connects to the inlet from the radiator) and on the 2RZ-FE and 3RZ-FE the thermostat is up high (they connect to the outlet hose going to the radiator). So on the 5VZ-FE it's for coolant drainage and for 2RZ-FE and 3RZ-FE it's for air relief? I am not sure I can come up with a rationale for this....

I'd have to defer to the FSM on that one.... :pat:

5VZ-FE
http://www.deserted1.com/FSM/Repair_.../ther/inst.pdf

2RZ-FE and 3RZ-FE
http://www.deserted1.com/FSM/Repair_.../ther/inst.pdf

 

Yeup... and see above for other links that were posted pointing to defining the purpose of the valve/hole.

If we're talking air bubbles, then it would make sense to have it up high - the bubble will want to float on the coolant.