T25 Coolant hose collapsing at high revs

[acornishpirate]

Hi all.

I've already posted earlier about my van misfiring at high revs/under load.

However, I've now noticed another issue which may or may not be connected. If I increase the revs to a certain point....guessing here but maybe 4000 rpm?, the rubber elbow in the coolant pipe back left of the engine completely collapses on itself.

Its the elbow in the run between the water pump and the thermostat housing just ion front of the bulkhead. This happens just before the engine starts to misfire.

Anyone any ideas at all.....I see there is a branch from this pipe which goes to the carb. Could this be the cause of my problems?


Cheers, Howard

[Oldiebut goodie]

Collapse says to me that the flow is obstructed and the suction of the water pump is causing it. I would take off hoses and pipes after where it collapses and check the bores.
Other than that a petrolhead will no doubt have some other ideas.

[boatbuilder]

Total guess but could it be that the cap on the coolant header tank isn't working properly, thus not allowing the coolant to flow from the expansion tank or allowing coolant into the expansion tank at too low a pressure?