Under Pressure?

[PeterC]

Can anyone absolutely confirm the right working pressure for the cooling system of a TVR Chimeara 4.5? Which probably means all TVR's using the Rover V8 engine.

The SH bible makes reference I think to TVR using the pressure cap from a MkII Golf which is rated at 12-14 lbs/in2.

However the Quinton Hazell parts reference book suggests that the MkII Golf pressure cap is rated at 1.3 bar which is 19 lbs/in2 in old money? And I am reliably informed that no other has ever been used.

Neither the original TVR cap or the QH after market cap appear to have any pressure rating stamped upon them. Can the higher rated cap be safely used?

The existing pressure cap is dribbling coolant when hot. This would suggest that a higher rated cap would offer a solutiuon. But will an increase of over 40% cause other problems with the radiator, gaskets, hoses etc.

[MickC]

Are you sure the existing cap isn't just broken?

I replaced my pressure cap with one bought from my local VW dealer (exact replacement as per the P/N on the cap) and have had no further problems (yet!)

[jonnyb]

Why dont you ask a TVR dealer? Then you will get the right one and its only about £6 anyway.

[PeterC]

I own two TVR sourced caps already, the original and one bought a few months ago. I have tried both without success, so thought I would try a different tack and hence the question that has arisen?

[peteA]

PeterC said:

I own two TVR sourced caps already, the original and one bought a few months ago. I have tried both without success, so thought I would try a different tack and hence the question that has arisen?

is the car overheating as the temp increase could result in a pressure increase? this would mean that the cap is working and the fault lies elsewhere?

[FunkyGibbon]

You might want to check that you are not overfling the expansion tank. With mine if the fluid is topped up above the seam (as they do on a service) the system will spit out coolant till the level is just below the seam. Once there it is fine.