Coolant levels slowly dropping? Also ID this part/sound please!

Soldato
Joined
25 Dec 2008
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5,976
Location
Sheffield/Norwich
First things first, what's the ? part on the pic below? There's a clicking noise that seems to come from that sort of area (might not be from the part though) - see video here (17MB warning sorry)

IMAG0211.jpg



Secondly, I've had to top up with coolant a couple of times over the last few months which obviously indicates a coolant leak somewhere. No oil in the coolant and no mayo in the oil level check or filler. No obvious leaks from any of the hoses in the engine bay - some miscellaneous fluid under the car since I parked it up yesterday but it's been raining and there were other damp patches around - and I got the coolant temperature up to 108°C (OBD info) with no apparent bubbling so my informal pressure test seemed satisfactory.

Thoughts anyone?
 
Charcoal cannister, something to do with emissions IIRC.

Coolant leak could be from a multitide of places, waterpump would be the worst. Look for white crystals/powder residue that coolant leaves as it dries
 
Cool, thanks. Do you mean on the pipes? Or just wherever I can see on the underside of the car/the soundproofing?
 
As said, charcoal canister, clicking is 110% normal don't worry, they all do it :)

As for coolant leak, not sure... check pipes, wet patches under car, thermostat etc that kinda stuff :)
 
Thanks for the info. Should I be overly concerned about head gasket at this point? My feeling was that it's unlikely given normal coolant and normal oil.. but it's obviously a concern I have :p
 
If its slowly and consistently losing coolant and has none of the other signs then it is unlikely to be your hg.

Get a torch and trace back every hose from the expansion bottle, as above check for white/green deposits, can be very hard to find if its just a small hole. Look at the rad, is that some sort of Vag? Drop the bumper (only a few clips) and check it from both sides

Oh check the cap too
 
Looks like a MK5 Golf/Passat.

I had a coolant leak which turned out to be the thermostat housing (apparently a common area in the VAG cars to leak from). Water pump was also changed at the same time, so I suppose it could have been that.

Tell us a little more about your car Make/Model/Mileage - last water pump change etc.
 
Mk4 Golf (V6, BDF engine), just under 140k.

I'm not sure when or if the water pump has been replaced. It doesn't look like it's mentioned in the service intervals as something that needs doing at a certain mileage/age - does it normally need replacing? Obviously people tend to do it at the same time as the cam belt but this has a chain so no changes.

Will do the above, thanks.
 
Alright guys, quick update:

Rate of coolant loss much increased (had to put in a few litres after a trip to Scotland, no overheating or anything - and chucked in a can of radweld while I was up there too 'cause I was bored) so finally got stuck in yesterday.

Piccies:





Took off the front and it quickly became apparent that something was not right around that plug thing (presumably a temperature sensor?).
The clip thing in the bottom pic looked a little rubbish but I presumed the problem was slightly further up with the seal around the sensor, so plugged it back in firmly with a liberal dosing of silicone paste stuff.

Now fingers crossed it solves the problem :)

Only had a couple of 'spare parts' after putting it back together, too :p
 
not sure tbh

i have removed countless of those clips from various places on vw engines

the one in my 95 golf (for example) is still original. they get a bit crusty but ive not seen them warp like that before
 
I was considering replacing it but unsurprisingly I didn't have the right part, and it was a Sunday. I've just put it in the other way round so maybe it'll straighten itself out, haha.

It's also conceivable that the reason it's a bit warped is because I may have pulled on the sensor to pull it out before noticing there was a clip on it, but I didn't think I put that much force on it!
 
thats more than likely why then!

also, those vr lumps have a water drain plug near the oil fitler housing (very few vw engines seem to have them!) which i think is really useful for draining/refreshing the coolant
 
That could be useful, I'll have to look out for it. My Bentley doesn't seem to know about it (says I have to remove two hoses) but it's unfortunately for the US models so there are one or two small discrepancies.

9L coolant this engine holds :eek:
 
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