Rad & Header caps.

[Mountain]

Are these supposed to be the same? In the member's area shop it says they fit both header and expansion tank.

I've noticed mine are very different. The rad cap is new and came on the new rad...it's 1.1bar which I believe is correct. I have a suspicion the header one is wrong....well was wrong.

The reason I'm asking is because I need a new one........Some idiot just lost it
Checked my coolant level, got a couple of hundred yards down the road and realised what I'd done....too late as it's nowhere to be found. Must have bounced into the grass verge somewhere.

So before I buy one the one in the members area it definitely fits the header too?

[missfixit70]

It's irrelevant what's on the rad as it doesn't have anywhere to vent to, it's below the waterline, so you don't want it venting. If it has got a vent pipe, it needs blocking off.
The header cap does all the pressure relief necessary, should be 1.1bar.
Have you checked it's not on the under tray? At what point did you realise

[Mountain]

No vent pipe on the rad.

When I heard a clunk and ran over it with the real wheel(I think)......then the penny dropped

Can't find it anyway, so I'm grounded until it arrives in the post. back on the bus to work for a couple of days then

How stupid do I feel

[Northern Bongolow]

you may need to order several lol as it will be about 6 months before you stop checking the coolant visually, and just rely on your gauges. mind you i think you have every right to be a little cautious with what you have been through

[daveblueozzie]

yellow cap on the expansion tank
red cap on the radiator.

[Mountain]

yellow cap on the expansion tank
red cap on the radiator.

Yeah, that's what I had on, which is why I was concerned about having the rad cap on both

I'm not convinced the rad cap will seal the header properly as the spring and rubber seal were a couple of mm shorter than the one on my rad. I don't want coolant leaking out of the header overflow pipe!

[missfixit70]

As I said it's irrelevant what's on the rad as it's got nowhere to vent to , as long as the top seal is ok, I'v seen straight caps, 0.9 & 1.1 bar on the rad & they all do the same job. Some of the cheaper replacement rads have the vent pipe which needs to be blocked, but you do not want the rad venting as it's below the water level so it'll just chuck water out.

[Mountain]

Don't think I've made myself clear . I'm not talking about the rad cap....that seals fine at the top seal which is all it needs..as you say.

My question is this....

In the members shop it says the rad cap also fits the header tank.

My concern is, the previous and the new rad caps I have do not have a long enough spring to form a seal on the inside neck of the header.

If I put my old or new rad cap on the header tank as soon as any pressure builds coolant comes out of the header overflow......due to the poor seal...due to the short spring.

So do the ones in the shop have a longer spring? I hope so because I've bought one.

[Mountain]

LOL That's the same as the one I lost.

The one on my radiator is different, the seal at the bottom doesn't have the metal 'collar' part and the spring is slightly shorter than the one I lost

I wonder if the depth of the recess is less on some pattern rads? As the rad doesn't need to vent it's only the top seal that really matters.

Can't take it off for a photo as I've just re-bled in anticipation of my new cap arriving!

As long as the new cap has a long spring to seal at the recess it'll be fine.

I was just curious because I have(err... had) 2 different caps.

Edit: Where'd the pics go

[missfixit70]

If you've bought one from Ian, it's a blueprint 1.1bar & it fits the header fine, just put one on mine (& it's not yellow )

[Mountain]

Excellent stuff

I've had to explain why I turned up at work on public transport today too

[widdowson2008]

LOL That's the same as the one I lost.

The one on my radiator is different, the seal at the bottom doesn't have the metal 'collar' part and the spring is slightly shorter than the one I lost

I wonder if the depth of the recess is less on some pattern rads? As the rad doesn't need to vent it's only the top seal that really matters.

Edit: Where'd the pics go

Sorry - senior moment. Here they are

[Mountain]

Sorry - senior moment. Here they are

Not as senior as losing one

[bongomaan]

i have lost two ,its the same one as the one on a shogun and availible from your local motorfactors...

[Mountain]

I think there's a few more that have lost one out there, but they are keeping quite

All sorted now anyway