Freelander 1 1.8 Inlet Manifold - coolant pressure device

AFS1 · Mar 1, 2018

Hi experts...... on the 1.8 K series the inlet manifold has a 'ball bearing' type (possibly pressure) device that controls the coolant (and attaches the coolant hose from the inlet manifold back to the expansion tank). Understand this sometimes gets corroded and stops working and I assume this then creates some type of back pressure and creates venting of the coolant via the expansion tank cap. I wonder what the thinking was behind this device and I'm aware a number of people just remove the ball bearing, and again I assume therefore that the coolant circulates from the inlet manifold to the expansion tank continuously. So anyone know how it was designed to work, and why and secondly, is removing the ball bearing a good or bad idea or should one just free the ball bering and de-rust it?

Thanks in advance.

Colthebrummie · Mar 1, 2018

All of that is news to me. I. Ist have a look when it stops snowing. My thinking would be to free the ball bearing if it is stuck.

Col

AFS1 · Mar 1, 2018

That's one option, although to free this, one needs to remove the inlet manifold, to get to the part. So do I remove it to prevent re-occurance?

rob_bell · Mar 1, 2018

It's what Rover called the "jiggle valve". It is there to bleed air bubbles safely back to the expansion tank. It's a useful function, and their getting stuck is thought to contribute to HGF.

To free them up is a case of removing the inlet manifold from the block and cleaning out any congealed gunk. I abused a jewelers screw driver to do this!

Removing the ball bearing will lead to a continuous coolant flow and pressure drop across the return rail. Probably not enough to cause significant problems with the thermostat, but not ideal. After all, Rover never did anything that would cost them another 1p in production cost...

AFS1 · Mar 1, 2018

rob_bell said:
It's what Rover called the "jiggle valve". It is there to bleed air bubbles safely back to the expansion tank. It's a useful function, and their getting stuck is thought to contribute to HGF.

To free them up is a case of removing the inlet manifold from the block and cleaning out any congealed gunk. I abused a jewelers screw driver to do this!

Removing the ball bearing will lead to a continuous coolant flow and pressure drop across the return rail. Probably not enough to cause significant problems with the thermostat, but not ideal. After all, Rover never did anything that would cost them another 1p in production cost...

Is it possible to check if it is working by removing the return hose from the outside of the inlet manifold - would one expect a continuous flow of coolant, a dribble of coolant, no coolant or something else?

rob_bell · Mar 1, 2018

I don't think that would help you particularly - but I think some have disconnected the pipe and then connected up a syringe full of coolant and tried to push this back into the coolant rail. It's a one way valve, and it should be possible to push fluid in that direction (to be honest, I've not tried! I've only spotted this as a problem on removing inlet manifolds) - if nothing moves, then I suspect you have a gunged up jiggle valve.

Nodge68 · Mar 1, 2018

The jiggle valve or giggle valve as I call them is designed to reduce the flow of coolant returning to the expansion tank, without impeding any air that needs to vent. Basically if there's air in the return, the ball drops under gravity allowing air to pass. However the ball is semi buoyant in coolant, so lifts up to impede the coolant returning to the tank.
To be honest I normally take the ball out, preferring the constant flow of coolant to the tank to help evacuate all air in the system.

The V6 uses the same manifold blead system as the 4 pot, but it doesn't have jiggle valves. In the V6, the coolant continually flows out of each manifold bleed to the tank, taking any air with it.

AFS1 · Mar 7, 2018

Nodge68 said:
The jiggle valve or giggle valve as I call them is designed to reduce the flow of coolant returning to the expansion tank, without impeding any air that needs to vent. Basically if there's air in the return, the ball drops under gravity allowing air to pass. However the ball is semi buoyant in coolant, so lifts up to impede the coolant returning to the tank.
To be honest I normally take the ball out, preferring the constant flow of coolant to the tank to help evacuate all air in the system.

The V6 uses the same manifold blead system as the 4 pot, but it doesn't have jiggle valves. In the V6, the coolant continually flows out of each manifold bleed to the tank, taking any air with it.

Having looked at this recently, the jiggle valve ball is a steel 'ball bearing' (although the early models it may have been plastic), so can't see how this would work, as a steel ball bearing couldn't be semi-buoyant in coolant - or could it?

Nodge68 · Mar 8, 2018

AFS1 said:
Having looked at this recently, the jiggle valve ball is a steel 'ball bearing' (although the early models it may have been plastic), so can't see how this would work, as a steel ball bearing couldn't be semi-buoyant in coolant - or could it?

I believe the ball in the jiggle valve is some form of alloy.

Freelander 1 1.8 Inlet Manifold - coolant pressure device

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