Club 80-90 Forums

I seem to be getting through these about one a year.I have always bought the cheaper of the two from brickwerks. Maybe i should be buying the more expensive ones in future.

R0B wrote:I seem to be getting through these about one a year.I have always bought the cheaper of the two from brickwerks. Maybe i should be buying the more expensive ones in future.

Yup.

no problem here with the cheaper oem manufacturer on two WBX
maybe indicates another problem?

I wonder what other problem could be ok for about a year before rearing its ugly head. Any suggestions?

Dunno just thinking outside the box

I think cooling system runs at 1 bar ish lets say you had a minute compression leak and were running slightly higher presssure or hotter., maybe that would be enough to kill the cap.

or maybe somebody put radweld in and its damaging the cap, or previous oil contamination eating the seals?

previous mix of pink and blue coolant causes sludge

only you know the history of the cooling system?

What happens when it fails Rob ?

Water overflows from the top up tank and the cap loses its quack.I can suck and blow through it. I am pretty certain there is nowt wrong with the cooling system.

OK, so coolant is being allowed to flow from the header tank into the topup / expansion tank to the point where it overflows

So, one of two things is going on, either

The 1 bar rating of the header cap has failed and coolant is being allowed to pass at normal system pressures, or
The cooling system is operating at more than 1 bar and so the pressure valve in the cap is working as designed.

As you know the lack of quack is indicative of the failure of the cap.

I assume that you buy a new cap and everything works as expected. Sounds the right thing to do to me. This time it might be worth fitting the new one, confirming all is OK again and then refit the old one and confirm that all is not OK ?

From what Brickwerks say the "Blau" product should be functionally the same as Genuine VW, as they are the OEM supplier. Why not see if you can get a replacement under warranty ?

The new one is acting as it should. It's not worth putting the old one back on as i know its given up the ghost. Not sure about the warranty as i bought three about two years ago to save on future postage costs.

This time it might be worth fitting the new one, confirming all is OK again and then refit the old one and confirm that all is not OK ?

Oh well, at least having them on the shelf means no delays in fixing your T25

Next decision, how many to buy next time ?

Heat degrading the rubber?

There is no rubber in the valve mechanism.

I have noticed that there is a max mark on the expansion (darle k )tank.maybe filling it to the brim is not what vw intended and maybe causes debris from the cooling system to collect in the darle k valves or wears them out because coolant passes back and fourth more often . I have noticed with my van that in practice an amount of air space can be left in the expansion tank and not be automatically replaced by coolant by the top up tank. I can’t work out if the top up tank is there to accommodate for lots of expansion/contraction or as a reserve in case of coolant loss.
E D I T- maybe the top up tank’s only function is to provide a way to top up the coolant from the cat flap.

I found that by reducing the level of coolant in the tank and fixing all those little leaks (drips) make a big difference. I still loose the coolant out of the over flow tank but think it’s got a crack in maybe? Not enough to worry about.


Sent from my iPhone using Tapatalk

The tank should be full to the brim from cold. This quote is from the Bentley manual.

add coolant until expansion tank is full and close tank with cap