Losing water Cerbera 4..5

[mangante49]

Noted last night that the temp was running too high on a run out only to get back and have steam from expansion tank.
Reading up it seems that this can be a common fault of the tank. Some people think it could be that the top is not secured on but wondered what other issues it could be???

[Gazzab]

There are two key contenders 1) Buy a new cap or 2) the pipework and connectors under the tank need attention (eg there is a 3 way plastic connector that can need replacing)

[jackwibble]

The cap has a built in release valve set at a specific pressure they can malfunction, it doesn't help to screw the cap on as tight as a hub nut as that doesn't effect the valve and can split the cap, its best to fit a genuine VW Polo cap if your replacing it.

From alternative parts list....
http://www.alexjudd.com/cerbera/parts/

EXPANSION TANK CAP
VW part # V443 121 321 "K41C Cover", also from German, Swedish, French (GSF) 174VG0130. £3 inc Vat

[FarmyardPants]

If it's the original rad they have tendency to develop small cracks that only leak under pressure. If a new cap doesn't fix it then that could be the root cause

[TimJM]

Have you recently topped up and put too much water in?

Mine runs around 1/3rd full when cold. When I put more in (just above half way) it blew some out - I replaced the cap anyway for a new one but only topped up to 1/3rd way and now the car is bone dry around the expansion tank and will sit in traffic for hours without issue at around 90deg (I have an ali rad and cooling mod chip so fans come in lower temp).

[Simonmiddleton]

Hi Mangante49,

I had a very similar problem a few weeks ago when the car had cooled down i topped up the expansion tank and left it for a few hours, when i returned the level had not dropped and no puddles under the car?
I put the expansion tank cap on then ran the engine, got the torch out and gave the accessible parts of the cooling system a check over, squeezing hose etc, and regularly checking underneath for drips and exhaust for steam (possible head gasket).
It wasn't until the thermostat opened (indicated by top radiator hose getting hot) that the drips of water appeared again, they were coming from the engine bulkhead area,
I traced it back to the white plastic 10mm 'T' piece which joins two 10mm cooling hoses from the manifolds on the heads and returns to the expansion tank via another 10mm hose.


I turned the engine off and when i pressed the plastic T it poured out, i let the engine cool then removed the T, i ended up replacing the three 10 mm hoses and jubilee clips as well, the T had gone very brittle from all the heat and i needed the car back on the road so i made up a temporary copper one using 3/8 copper pipe, its a lot better than the plastic one and wont go brittle so i may end up leaving it on there

[morebeanz]

You can buy an upgraded metal Y piece to substitute for the T piece already. I added it when I replaced my water hoses for silicon ones and the front water pipes for stainless.

[wiggycerb]

morebeanz said:

You can buy an upgraded metal Y piece to substitute for the T piece already. I added it when I replaced my water hoses for silicon ones and the front water pipes for stainless.

Can you remember where from ?

Thanks

[Mad Mark]

i bought my replacement 'y' piece from a local corner car shop. But Power sell them as the others i believe.


My expansion tank split at the top where the small hose enters it. But it was surprisingly easy not to spot it.

[Tanguero]

I got one from fleabay

http://www.ebay.co.uk/itm/BRASS-BARBED-METAL-Y-PIE...

[Supateg]

Tanguero said:

I got one from fleabay

http://www.ebay.co.uk/itm/BRASS-BARBED-METAL-Y-PIE...

Me too, also got one for the breather four way line too

[Mr Cerbera]

Had exactly the same symptoms with the same cure.
(I bought a plastic 'Y' piece from a garden centre until the brass one arrived via post)