Pressure in Cooling System?

[AlanJHart]

Dear All,

Just had a fab drive down to Windsor to the Motor Museum in Eton Dorney ... however ...

A bit puzzled! My cooling system seems to be pressurised - even when cold. By pressurised I mean quite a lot of pressure when I begin to release the cap from the expansion bottle ...

Not sure but can these be linked:

1. Pressure in cooling system
2. Car when run for a while has a slight mis-fire
3. Had to replace ignition coil because previous one I think had been overheated

The temp gauge reads normal. Engine was rebuilt about 3K miles ago with new heads, thicker gaskets, new timing gear, new radiator etc ...

I have in my mind that perhaps the gasket is going - hence the pressure and the slight mis-fire?

Anyone had a similar issue?

[wilf]

Do you have a header tank, or the original expansion bottle?

If the latter, how full is it?

You are right in that what you describe is often the symptom of a failing head gasket. Get a local garage to check for combustion gasses in the coolant to be sure one way or another.

[V Mad]

Did anyone retorque the heads after the engine rebuild? If not that may have allowed the gaskets to leak.

[AlanJHart]

Hi,

Many thanks for the quick response.

Yes, the heads were re-torqued after the rebuild and checked again at 1000 miles - with the engine cold.

I have a bottle. It's usually full - but I fill from the top and the car is always "pointing upwards" ...

I'll get it checked out at my local Triumph specialist, Enginuity over in Acton ...

Many thanks

Alan

[stag-phil]

Hi Alan

The expansion bottle should not be full, a third full is normal.

Phil

[AlanJHart]

Hi Phil,

Yes, should be but I think due to the pressure build up it is getting full?

When I release the cap I have to very gradually - even when the engine is cold ... otherwise a big "whoosh" of coolant follows!

Alan

[Andy Rundell]

sounds like it could well be HGF(s), save the guess-work - time for sniffer-test/blocktester

......... Andy