Hi all I'm looking for a part number on our 8p4 TDI, the small hose that connects to the top radiator connector and goes to the return, it has a little filter or something inside and I can't unblock it so looking to replace just that bit

Edited November 8, 2025Nov 8 by mikeloretta

Welcome Mike and thanks for joining.

Have a look at LLL Parts website, and that is likely to come up with the part no. for you.

Regards,

Gareth. 

Thanks, I've managed to find a complete set of pipes for £20 off eBay so hopefully that sorts the problem, it seems that there is good flow from the little tee at the top coming out of the radiator but the other end of that pipe where it joins 2 others there is no flow, I tried unblocking with carb cleaner etc but no joy, I'm assuming the little plastic piece I can feel within the pipe is some sort of filter which is completely blocked, hoping that this is the cause of blowing out all the coolant from the reservoir, already tried a few other cheap fixes like coolant tank and cap and thermostat ( what a pig of a job to do!) without success so fingers crossed! Ah and there is no sign of it being head gasket, car does not overheat, no cream in the oil and no oil in the coolant, also no smoke from the exhaust and 2 sniff tests passed

Thanks for the update Mike,

Personally, I would never use carburettor cleaner on any rubber component.

20 hours ago, Magnet said:

Thanks for the update Mike,

Personally, I would never use carburettor cleaner on any rubber component.

TBF I did try a few other things first, it was definitely a last resort

So the issue persists, not as bad after I replaced that small bore pipe which did I deed have a small plastic restrictor inside that was blocked solid, the car lasted 4 days before I had to add coolant this time instead of every day, so I'm sorting of hoping that it's only blown the coolant out because of air that I introduced in to the system which has now forced it's way out so we will see what happens next!

Thanks Mike,

Could well be due to an air lock - let’s hope so.

Please let us know how things progress.

Regards,

Gareth. 

 

Update time, it's still blowing coolant out, not as often but still happening! I think my next port of call will be the heater matrix, I need to give it a flush as talking to my daughter who's car it is the heat inside is inconsistent, sometimes nice and warm other times not very much at all, after that I really do not know what to look for next

Ok so ended up replacing the matrix completely, horrible job!! Water issue seems to be better now but still not getting heat in the car, recap is replaced coolant tank and cap, new thermostat, replaced a blocked hose, normal operating temp, no smoke, no sludge in oil or coolant. think we might just sell and move on to something else as I'm flumuxed with this now

What was blocking the small bore pipe? I ask in case the car is one of those affected by rupture of a bag of silica gel. If so, the whole coolant system needs to be flushed thoroughly to get rid of the evil stuff.

See this:

 https://www.youtube.com/watch?v=39ngHGvMzEg

 

Edited January 25Jan 25 by cliffcoggin
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