VW header tank cap keeps breaking?!
FASTdan - 4/6/10 at 02:03 PM
This has happened twice now on our header tank. The tank itself is a VW/Audi one, a round tank with a fairly flat cap - the previous builder said it
was a golf header tank, but not certain.
The cap is really stiff to screw on and off - presumably due to the friction between the O-ring and the middle 'neck' on the tank itself.
Over time the first one got stiffer and stiffer until the cap eventually broke. Prior to this it had become so stiff that you almost required grips to
be able to unwind the damn thing!
The same has happened again with the replacement.
Anyone else had this, or have we just got a defective tank or something?
Its a strange failure!
To look at there doesnt appear to be anything obvious at fault.
BenB - 4/6/10 at 02:05 PM
A reasonable thing to try would be some silicon grease to lube it up!!!
FASTdan - 4/6/10 at 02:05 PM
The tank can be seen here:
FASTdan - 4/6/10 at 02:07 PM
quote:
Originally posted by BenB
A reasonable thing to try would be some silicon grease to lube it up!!!
IIRC I think we did that on the first one - although not silicone grease, probably just regular grease lol.
BenB - 4/6/10 at 02:10 PM
quote:
Originally posted by FASTdan
quote:
Originally posted by BenB
A reasonable thing to try would be some silicon grease to lube it up!!!
IIRC I think we did that on the first one - although not silicone grease, probably just regular grease lol.
Could be why it keeps on breaking then 
Non silicon greases can be a bit harsh on plastics....
James - 4/6/10 at 02:33 PM
On my Mk2 Golf it can be blinking hard to get it undone.
I've not been able to undo it sometimes and resorting to using a ratchet extension bar each side of the lid and turning them together.
HTH,
James
Dingz - 4/6/10 at 07:26 PM
The O ring will be suitable for hot water/glycol, not mineral oil/grease, it will cause it to swell up. Silicone based grease will be fine.
02GF74 - 4/6/10 at 08:04 PM
quote:
Originally posted by FASTdan
The tank itself is a VW/Audi one, a round tank with a fairly flat cap - the previous builder said it was a golf header tank, but not certain.
The cap is really stiff to screw on and off -
are you sure it is the corrcect cap?
they are an easy fit, not requiring any lubricant and should only get a bit harder to do when the o-ring gets compressed and you run out of thread.
Or could it be the tank that is at fault.?
suggest looking on ebay for a similar tank complete with cap and swap over.
FASTdan - 5/6/10 at 08:40 AM
quote:
Originally posted by 02GF74
quote:
Originally posted by FASTdan
The tank itself is a VW/Audi one, a round tank with a fairly flat cap - the previous builder said it was a golf header tank, but not certain.
The cap is really stiff to screw on and off -
are you sure it is the corrcect cap?
they are an easy fit, not requiring any lubricant and should only get a bit harder to do when the o-ring gets compressed and you run out of thread.
Or could it be the tank that is at fault.?
suggest looking on ebay for a similar tank complete with cap and swap over.
Yeah I think we'll have to do that - was just wondering if others had experienced this (assuming this header tank is a commonly used one).
Didnt know that about mineral grease though 
[Edited on 5/6/10 by FASTdan]