I have to agree.
My 6 litre is fitted with a cathouse spares stainless crossover which are not fitted with the valve in question. I have never had a cooling system temp. problem or bleed issues.
Been a few days driving recently with temps in the low 40'sC a/c on and needle does not move.
Seems odd to incorporate a device aimed at controlling the air in a sealed system that should have NO air to begin with if filled properly with coolant.

 

That's the one, yes





Heh heh, I'm left with my head still spinning a bit

I'm gonna remove the valve and 'call it good'.

Cheers
DD

 

Doug, That is exactly what the Wizard of Oz did, and told us to do many posts back! So now that the Sage of the Seattle is of the same mind, we mortals can regard the matter as agreed!
Greg

 

Was noodling around today .....slowly progressing on my V12 project....and decided to install the water pipe. Took the little jiggle valve out, as I said I would. I must say I felt a bit cowardly and wishy-washy doing so.

I sorta feel like I should've "taken a stand" on the issue

Cheers
DD

 

The "Sage of Seattle", LUV IT.

 

Just a thought, maybe the check valve is only there to assist the bleeding of the radiator during filling (in an attempt to make it idiot proof, particularly at the factory) in which case it should flow to the filler, if the system is leak free (air in as well as coolant out) and it has been filled/ bled correctly and maintained there should be no air accumulating at the filler during running and if it does it is inconsequential. If that air does make its way back into the engine it will end up at the top of the radiator and be bled out via the banjo/ venturi set up or bleed from the L/H t/stat housing (via the balance tube) through the venturi tube when t/stats are open.

Thinking about it more, if coolant is allowed to flow to the radiator from the filler it will increase the warm up time, which is unacceptable as far as EPA is concerned.

 

After careful analysis my take is that the jiggle valve does in deed have real application in the system. The best way to explain it is to fisrt note the operation of the
bleed piping on the top of the radiator. At the left side (US cars) there are connections from the left thermostat housing and to the expansion tank.
These two connection produce a venturi effect where coolant is always flowing from the thermostat housing into the expansion tank.......this effectively is a suction pump for the connections on the right side banjo bolt. The banjo bolt connection to the top if the radiator and the fill tube (through the jiggle pin). Effectively the is a suction created from the fill tube and top of radiation to the expansion tank. (suction to expansion tank)

The main purpose is the pull any accumulated air from the top of the radiator and the fill tube. For the fill tube connection the jiggle pin will be open when there is air in the fill tube. In this state the venturi effect will pull the air out of the fill tube while the water pump pressure will fill the tube with coolant. Once the level of coolant hits the jiggle ball the jiggle value will close. In this state the suction is only applied to the top of the radiator. If air enter the fill tube the jiggle opens and the process repeats.

One critical area of this design is to protect the water pump from any air infiltration which would diminish the pump operation. Specifically the jiggle circuit is at the highest point of the pump cavity. Between the suction of the venturi and the pumping of the coolant these two forces would serve to remove air and maintain an adequate coolant level for proper pump operation.

Hope this helps,
--Joe