Stat - Jiggle pin

[miked]

I believe the little valve/pin on the thermostat is called a "Jiggle" pin (or joggle in USA). I have had trouble in the past when filling up and air locking under the stat?. Even when bled at the heater hose beneath the stat (Plus 2 set up, no valve). I only run a 4 lb cap (save stress on pump seal) and end ups with a surge and bottle overflow at the first opening of the stat. Then the drawback of the entire bottle (and some more). I will fit a 7lb cap now. However the recupe part works like magic after the first stat operation with the 4LB, that?s why I left it in place. I do have a high point with a Car Builder Solutions type top hose filler neck.
I have looked in the archives about this subject and saw Steve WW?s posting about drilling a 3mm hole in stat?s (without jiggle pins available).
Last night I took the housing off to get the stat out, water sat on top! To my surprise I found that on the inner valve was a little brass jiggle pin. It was stuck solid. I cleaned the stat and put it in boiling water etc and have now put it back. I am sure this was one I fitted last year. Can?t recall where I got it from. I do recall from the 70?s etc when you used to see a little nylon ball underneath with a little ?C? shaped tail.
Am I right in thinking that stats with these pins are rare or have I just missed it as it was sat on the inside of the valve part (used to be on teh outer flange part). I have not started it yet but may with the 4LB just to see what happens. Should the system self bleed now I have the pin working? Maybe the heater circuit is the culprit. I always let water come out of the top heater pipe by pulling it off the stat? housing hose tail.
Perhaps the 4lb encourage early release?

Any views?

Mike

[Tonyw]

Mike,

The little jiggle pin as you call it do not useually get seen here in Australia, there is just a small bleed hole, I would think no harm would be done if you simply removed the jiggler and left a hole there so it can just bleed out any air.

Tony w

[GrUmPyBoDgEr]

Hi Mike,

I agree with Tony, a thermostat with just the small hole without the jiggle pin will help bleed the system when filling it.
As you know system bleeding is first complete when the thermostat has opened & of course the coolant has filled the heater system.
Thermostats with the jiggle pin provision should be freely available.
Should you not be able to find one locally I may be able to find a new one in my "box of bits"

Cheers
John

[miked]

Thank guys. I will see how this goes and next time I drain down will check the pin to see if it is still free. If not I will remove it and live with the hole. Meanwhile I will find the spare ones and check them out for this featrure.

Mike

[ardee_selby]

I do recall from the 70?s etc when you used to see a little nylon ball underneath with a little ?C? shaped tail.

Mike

Yes, I recall them. Also seen them, and ones with jiggle pins, referred to as having a valve for air bleeding...but can't think how a one-way valve would be needed in lieu of a plain hole....

Cheers - Richard

[GrUmPyBoDgEr]

I do recall from the 70?s etc when you used to see a little nylon ball underneath with a little ?C? shaped tail.

Mike

Yes, I recall them. Also seen them, and ones with jiggle pins, referred to as having a valve for air bleeding...but can't think how a one-way valve would be needed in lieu of a plain hole....

Cheers - Richard

Hi Richard,
it makes sense in theory but in reality the hole's cheaper, does the job & the system internal leakage over that hole is not even worth calculating.

Cheers
John

[nomad]

A trick I often use to get air out of a system is to give the bottom radiator hose some serious squeasing. Tends to burp air out of the system and get things circulating. Should get air past the jiggle valve.

Kurt.

[miked]

Hi Kurt,

I also do that squeeze thing on the bottom hose.

Update. Started it this morning with a fresh refill and the free jiggle pin. Engine warmed and pushed a small amount out of the overflow into the recupe bottlle then the stat' opened and all warmed through. I took it for a couple of mile run. Temp fine. This was with the 4LB cap on just to see.

So free jiggle works fine with no trapped air under the stat.

Mike