B5.5 Passat coolant problem

Hi guys,
I've written this up on the UKPassats & Edition38 forums, but thought I'd stick it up on here too...



So, I bought my B5.5 130PD TDI about 7 weeks ago. 5 weeks ago the coolant needed topping up.
Filled it to the brim. 2 weeks after that, coolant sensor kicked in and displayed the warning on the dash.
Topped up the coolant again.

It's been like this for the past few weeks, so I decided to do some investigation.
When filling it up I noticed the small little overflow pipe at the bottom of the coolant bottle.
Looked on the chassis directly underneath and a slight bit of residue. Thought it was odd.
So yeah, filled it up, and took it for a drive to Halfords (roughly 15 miles, no thrashing it).

When I got back, I opened the bonnet and looked down on the chassis (not sure what its called, but directly under the overflow coolant pipe from the bottle) and noticed it was wet.
This was dry before the drive.

Now, my first guess is that pressure is building up whilst driving along, forcing the coolant out of the overflow pipe from the back of the bottle.
No smoke comes out of my exhaust (its a TDI and it never really black smokes when punting it either) and no milky residue in the oil filler cap so i'm guessing the HG is ok.
The temp gauge doesn't go over 90 so it isn't really causing any impact to my car other than having to fill it up all the time.

I've narrowed it down to either a broken waterpump (rotor is broken?) or a leak in the radiator (corrosion?).

Would this sound right?
And can I get a heavier duty waterpump fitted (metal rotor?) and what sort of price would I be looking at?

It would help to be armed with this info before getting r@ped by the local spanner monkeys...
Any help is VERY appreciated!

Cheers,
Stamps.

Check the expansion tank cap has been changed (they leak after a few years, and they drip out from the bottom if the bottle) I have changed mine recently due to the same issue. Fine now. Next thing i would say is the water pump blades or shaft seal. Again I changed mine to a metal bladed one.

HTH dude.

Hope im not insulting you here stamps but sure its not just over filled each time? Think the max mark is about in the centre of the expanion bottle where the seam is almost. Not 'up to the brim' like in your post (though could just be an expression when you say that)

If its not being over filled in the first place and it is still leaking from the over fill pipe then i'd say lupton is right with the pressure cap being at fault.

If the temp gauge isnt getting overly hot and your heaters in the car still work then your water pump will be ok i would think.

If the radiator is leaking then there will be coolant dripping from underneath or getting caught in the undertray.

And yeah the replacement water pumps are normally ones with metal rota's

i have a spare cap that i had for my 18t passat if u want it i dont need it

Is there a large amount of pressure when you release the cap ?

Its not unusual for the cap to screw up.
If you are worried about the head gasket being gone you can pop round and I can test it for you with the 'sniffer'
Always get a genuine cap and always a metal bladed pump.

you have my number