pressure cap seal

[BERGS2]

got a new 15lb pressure cap for the swirl tank over the weekend -

seems to have a pressure seal on the sprung piece but not one for the main body of the cap.

I've got a vague memory of people making washers out of innertubes to fit these...

does the top of the swirl tank need to be sealed or does the pressure release seal do the trick?

[WildfireS3]

Does the spring compress? Mine didn't and I was advised to use a 10lb one with extended spring. I bought a second cap, took it to peices and also got a new seal in rubber. This way the spring extended out and actually compresses on the swirl tank.

Best make one out of an inner tube as well there.

[Rower]

The extra rubber washer does the trick, I have a few, if you email me via my profile I will send you one.

[greenv8s]

You should have a blank cap on the swirl tank and a pressure cap on the expansion tank. The reason the pressure cap doesn't fit the swirl tank properly is that it wasn't meant to! Having said that, people fit the caps both ways round without major problems - getting both caps to seal is probably the most important thing.

[shnozz]

oh dear, the pressure cap debate once again

i swapped mine to a 15lbs cap from halfrauds and mine was always on the swirl tank no problem. I replaced it due to hearing a bubbling sound from the engine bay after the engine was switched off and on closer inspection it was water escaping to the expansion tank.

[Le TVR]

shnozz said:

oh dear, the pressure cap debate once again

Dont go there, please.....

[peter m]

I recently bought a QH FC49 rad pressure cap for the top of the swirl tank, long reach 10lb. The cap did not come with a large washer to seal the top, so when the pressure gets up the cap would leak instead of overflowing to the expansion tank. An old washer from another cap solves the problem. I don't know why they don't provided these anymore.

Pete