temporary water coolant loss - pushing all out expansion

[droppedvalve]

This is a curious problem. Recently fitted new water pump and thermostat from Brickworks. All running fine for many miles (run to Dawn to Dusk 24 hour enduro in the hills near Neath as crew chuck wagon so 500 miles or more without problem).

Until this week however, for some reason I ended up with all my coolant in the rear, expansion, bottle. This happened after a long run from Dunkirk, I dropped down into Boulogne (long uphill followed by long downhill) and the led light started blinking, temperature guage normal. Pulled over to find the rear bottle overflowing, took engine cover up and all seemed OK, engine bottle half empty (it had filled expansion bottle) and no hoses/joints leaking.

Rad was clearly emptry, no pipe leaks or unions off, no leak from pump or thermostat housing.

It is as if the pump had temporarily failed, or something had temporarily gone wrong with system pushing all out as expansion without raising the gauge.

It took some time to get rad filled, it was empty, left it running until happy to move on and it appears all fine. No light flashing. Seems fine again since.

Interestingly this happened once before to my old AAZ engined bus and as it happened only that once without repeat I never worried too much.

But here it is again, with my JX and I'd like to know what is going on, the science behind this happening.

Has anyone else had this occur and anyone an explanation and solution?

ta

[Titus A Duxass]

Firstly welcome, you'll probably get a ticking off for not saying hi first.

Second, your JX Head gasket could be on the way out (sorry).

[Red Westie]

Replace the radiator pressure cap as a matter of cause, check the thermo rad fan is operating correctly (a little over half way) and the thermostat is correctly opening by feeling the pipes.
This maybe a head gasket but rule other things out first.
Martin

[droppedvalve]

Firstly welcome, you'll probably get a ticking off for not saying hi first.

Hello all, I have been trying to get my registration sorted for many months and perhaps I may be a few brain cells short as I did find it extraordinarily tricky.
Anyway it now works so fine and thanks for the reminder prompt.

Good to be here.

Laurence

[droppedvalve]

Second, your JX Head gasket could be on the way out (sorry).

New head, new gaskets, new head bolts, new thermostat, new pump, new rad fan switch. All less than 1000 miles.

I do wonder about the rad pressure cap though. Could this explain it? does it fail, letting it air and then reseal itself?

If I can't narrow this down I may have to lift the head to check it all out again as not happy as it is, though it may not happen again (as with my AAZ)

before I go to such extremes need to work out all possible causes. Thanks for being brutally honest, appreciated!

[Titus A Duxass]

In that case it may be worth giving it a good bleeding then.
There's an article in the wiki about bleeding - https://club8090.co.uk/wiki/Co ... ing_system

I said head gasket from experience.

[droppedvalve]

This maybe a head gasket but rule other things out first.
Martin

Thanks Martin and I wonder what you may say the signs of a blown head gasket may be?

I know lack of power, oil in water/water in oil (but not always).

I wonder if such a funny thing happening may be a clear sign of something. What could cause the water to 'expand' out in such a manner?

Why is the head gasket a possible? (Science please, if you've the time that is)

Heard of water pump failure as a possible cause, though it is working fine now, and was new 500 miles ago.

No visible signs of any water loss anywhere other than the overflowing expansion bottle at the back. and now it appears all happy again, power is normal, oil normal.

ta

[Titus A Duxass]

Why is the head gasket a possible? (Science please, if you've the time that is)
ta

Combustion gases being forced in to the cooling system and pressurising the whole system and forcing the coolant out.

Mine did this several times before the head gasket really let go. What was interesting was that the temperature gauge hardly moved through the whole performance. We worked out that the temp. sender was no longer in coolant only air (coolant level dropped too low).

[phredd]

Just a thought >>> Have you replaced the Dalek Cap ??

It may be blocked in one direction only and not letting coolant return to the engine.

Phredd

[droppedvalve]

Just a thought >>> Have you replaced the Dalek Cap ??

It may be blocked in one direction only and not letting coolant return to the engine.

Phredd

Right, said Phredd, I will get a new one.

Happened again to me on way back to ferry. No flashing lights. More bad smoke for a few miles after. Ran back to town with the heater on full (ready to bleed more air from the system) and found it did not suffer the same so that appeared to relieve the pressure in the system to avoid throwing the coolant out the back.

Going to check right round and fit a new cap but may lift the head to check out what may be going on with the gasket.