Header Tank Caps

Big lumps of metals and spanners. Including servicing and fluids.

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R0B
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Re: Header Tank Caps

Post by R0B »

I don't think there is as i don't think any other vehicle has our system. But beware of buying a similar cap off eBay.I made this mistake thinking i was getting a bargain as no postage. This one had no quack, you could suck and blow through it. Needless to say i returned it pronto.

Is there an "upgraded" cap available, maybe from another model.
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Re: Header Tank Caps

Post by itchyfeet »

my money is on the seal degraded by something in the cooling system.
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Re: Header Tank Caps

Post by R0B »

It had crossed my mind. But what? Apart from coolant and the remnants of Kseal there is nowt else in there. Maybe it's the local water :?
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Re: Header Tank Caps

Post by itchyfeet »

oil perhaps from a previous contamination?
maybe K seal is enough who knows whats in it?
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Re: Header Tank Caps

Post by R0B »

Methinks Kseal is the culprit.
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Re: Header Tank Caps

Post by CJH »

Rob - what makes you say that it's no good? Is it that it doesn't quack, and that you can blow and suck through the nozzle? I had a new one that was the same, but I realised that the rubber washer that holds the valve in the cap will only seal when it's screwed down onto the bottle. Without that, I think air can get past the washer, and that's more likely I guess when the washer is older and may have shrunk a bit. So as far as I could tell, the suck/blow/quack test isn't conclusive unless you do it in situ, screwed down tight on the bottle. Goes against the common wisdom I know, but now that you've had yours apart, would you agree that it's only the tightness of that washer in the recess that would prevent air passing, but once screwed down the washer will compress and make a seal?
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R0B
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Re: Header Tank Caps

Post by R0B »

Screwing the cap down does not make any difference, i have a spare tank here and have tried that.I can still suck and blow through the cap.
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Re: Header Tank Caps

Post by CJH »

Ah, right. No good then.
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Re: Header Tank Caps

Post by Cecil »

Thanks silverbullet. yes that’s the book I meant.Thanks for showing it.

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Re: Header Tank Caps

Post by Cecil »

After 1years use The Blau cap I dismantled took considerable force to lever apart and traces of blue plastic were left on the black plastic and vice versa. Of the 2 other new unused Blau caps I bought (at the same time ) one has the black part secure and the other loose.Of the 2 (certain vintage) genuine vw caps I have the black part is secure on both.

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Re: Header Tank Caps

Post by R0B »

Do your secure and loose ones quack?
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Re: Header Tank Caps

Post by Cecil »

Yes The new one with loose black part quacks.
The one I prised apart now quacks ,having dismantled and cleaned its valve ,the black part is now loose fitting!
The others quack except the vw original which is why I have removed it.

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Re: Header Tank Caps

Post by lefty67 »

Apparently vw stopped supplying/manufacturing the black caps in December 2017,
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Re: Header Tank Caps

Post by Simon Baxter »

Blau internals are the same as VW, just the outer that's different.
Blau were the OEM for VW.
Quack or lack of quack doesn't mean the cap has failed, once full of coolant they tend to be muted..
Just sounds like there are other issues to me, they aren't called wasserleakers for nothing.
Cap needs to be screwed onto a header tank to compress the valve assembly into the cap to seal it.
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Re: Header Tank Caps

Post by handsmann »

Simon Baxter wrote:Blau internals are the same as VW, just the outer that's different.
Blau were the OEM for VW.

One thing I know for sure, my Blau from Brickwerks bought this week does not dribble coolant down the top of the tank, doesn't hold in more pressure than (I think) it needs to and seems to pull a little coolant (50 - 60 mm) back from the overflow tank when cold. Worth the money and an immediate improvement over a tired original and what seems to be a sub-standard Febi part.

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