WATER/COOLANT LEAKING FROM EXPANSION TANK

[KOMET CREW]

Hello everyone (first post),, I have a t25 Komet 89 reg 1.9 petrol engine,, during a recent trip to northwales,, on arrival noticed water dripping fron van,, on looking it was coming from the expansion tank,, drove home and didnt occur again,,next weekend drove about 150 miles no problems,, last weekend did about 50 miles ,,when i got home there was the drip again from the expansion tank,,on feeling the water it does seem to have a viscous feel to it,,but i do put the correct vw coolant in the system,, the water is around the rubber(think its a scensor) in the top of the tank and on the platform under it,,there is no oil in the water and no water in the oil so hopefully not a head gaskit,, the van is running fine,plenty of power and as i said have done a few miles since i discovered the problem,,was wondering if it could be a faulty thermostat or does the whole expansion tank need replacing,,, the tank is full to the top as it should be,, thanks in advance for your replies,,, Chris

[Smiffo]

Do you mean the header tank? ( The one with the coolant level sensor in it. )

If so, it might be that your `dalek` cap isn't allowing coolant to flow to the expansion tank when needed?
Or it could just be the sensor seal is naff and that is the weakest point, so leaks when pressure rises?

My coolant has a viscous feel too - it's 50:50 mix, so that doesn't mean anything is wrong with yours per se.

[California Dreamin]

Dito..coolant level sensor seal although carefully examine the tank for cracks as they are common. I would also check the darek cap for correct operation and replace if in any doubt what so ever...

Martin

[Oldiebut goodie]

I had a sensor that leaked up through the two metal prongs. Hard to spot that!

[CovKid]

As I recently discovered,the spout on the dalek cap can develop a tiny crack (often hidden) which will let water out under pressure or they can leak via the threads. They do go brittle after a time. If there, its hard to spot as it can pool around sensor making the sensor seal appear suspect when its actually the cap. The tank itself can also go brittle and split. Also. cheaper expansion caps (the one with the blue triangle embossed on top) are so badly made you'll only get one in every 50 thats any good or that will last. GSF only sell those ones. I wish they'd give up on them. The ones made by Blau are the best made ones. I'm not particularly brand mad, but the cooling is crucial. Any probs with the cap and the water level will regularly drop in that tank and the excess in the other won't get sucked back in, and then the coolant light will start flashing again.

[KOMET CREW]

Thanks very much for all the very useful replies,, much appreciated,, looks like the culprit is the Dalek cap or seal,, so will renew both,, if i was to go ahead and renew the whole expansion bottle,, is it a big job and do you have to bleed the whole system again,, thanks,, Chris,,

[kevtherev]

buy a brickwerks cap to ensure you don't get a useless one

[CovKid]

I just bought the same one (Blau) from ebay for under a tenner (yes it quacks) but think I got the last one. As I mentioned, avoid those with a triangle embossed on them. Loads of those around but its a false economy.

Ah, found another http://www.ebay.co.uk/itm/VW-Transporte ... SwbdpWarVf" onclick="window.open(this.href);return false;

Simplistic rule of thumb seems to be:

Triangle (poop)
Circle (OK)

You'll need to bleed cooling system too as the level at radiator end will almost certainly have dropped too.

If its any consolation, I had similar issues. New cap and bleed should fix it - unless you are sucking in air somewhere else in the cooling system.

[KOMET CREW]

Thanks for replies .. Have now ordered a new tank from heritage people which includes a new cap.. Also bought a new tank level sensor to go in it.. Bit worried about bleeding the system though.. Any info much appreciated.... Cheers Chris...

[California Dreamin]

Clamp the pipe off going to the tank, remove the old one, fit the new, fill to the brim, undo the clamp....I'd be surprised if the tank needs more than an egg cup full to take it back to the brim again, fit the darlek cap, ensure the overflow tank is filled to the line...NO BLEEDING as you have not introduced any air in to the system.

Martin

[KOMET CREW]

Thanks for that martin... Will save me a load of hasle.. Sorry to be a pain.. But what sort of clamp would I use to block the pipe off with... Could I just bend it up on its self and tie it up while change tank..Chris..

[multisi]

Thanks for replies .. Have now ordered a new tank from heritage people which includes a new cap.. Also bought a new tank level sensor to go in it.. Bit worried about bleeding the system though.. Any info much appreciated.... Cheers Chris...

The cap that comes with the tank may not be good one, get a cap from brickwerks to be sure !

[captain Byrne]

Thanks for that martin... Will save me a load of hasle.. Sorry to be a pain.. But what sort of clamp would I use to block the pipe off with... Could I just bend it up on its self and tie it up while change tank..Chris..

Will probably be fine to bend it up & tie it but if you can I'd be tempted to use mole grips or similar to fully clamp the pipe. It's not under any pressure so you're not likely to loose much water. If you don't have mole grips then improvise by screwing two bits of wood together with the pipe inbetween.

[California Dreamin]

I've got two girling pipe clamps like these:

http://www.ebay.co.uk/itm/Laser-4976-Ho ... 1X6Cs6LJpw" onclick="window.open(this.href);return false;

But the cheaper sprung ones will work fine....very useful tool if you own a T25...lol.

http://www.ebay.co.uk/itm/DRAPER-HYDRAU ... SwxCxT64rq" onclick="window.open(this.href);return false;

Martin

[KOMET CREW]

Thanks everyone for your help,,, those clamps look the part,, didnt even know they existed,,,,cant believe how good this website is,, a mine of information!!!!! cheers Chris...