VW Golf (2004) Coolant Loss???

crosstownk

Here's a bit of a stumper.

2004 Golf, TDI. Looses coolant about 1 litre every 3000kms or so. No evidence of a leak - no pink crusty coolant anywhere. No change in oil level or oil quality and no evidence of white sludge in the oil. No excessive steam from exhaust. Replaced expansion tank cap just in case.

Sent car to main VW dealer to investigate. They found no faults. In the end they diagnosed a faulty cylinder head but couldn't be 100% sure why it was at fault - all they could say was that "it cured the problem on another Golf with the same symptoms" and replaced it (warranty) - but guess what - the car is still loosing coolant:eek:

It's possible that the coolant is venting as steam somewhere - but no evidence of any leak is visible.

Anybody any ideas, anybody?????

BrianD3

Heater matrix maybe? A slight weep from that might produce no symptoms or signs of a leak, the coolant might pool somewhere and be dispersed into the outside air when the car is driven at speed. The matrix is probably buried in the dash and impossible to check without removing the whole thing.

crosstownk

BrianD3 wrote:

Heater matrix maybe? A slight weep from that might produce no symptoms or signs of a leak, the coolant might pool somewhere and be dispersed into the outside air when the car is driven at speed. The matrix is probably buried in the dash and impossible to check without removing the whole thing.

Coolant system was pressure tested and no loss in pressure was found. Its possible the leak only happens at certain temperatures and the pressure test may have been done when the engine was cold (most likely).

lomb

or the heater matrix was closed at that cold temperature?
u need to add a ultraviolet dye to the coolant and check in 2 or 3 weeks where it has leaked. i wouldnt personally let anyone near the cylinder head of my car without doing that test. cowboys..

crosstownk

lomb wrote:

or the heater matrix was closed at that cold temperature?
u need to add a ultraviolet dye to the coolant and check in 2 or 3 weeks where it has leaked. i wouldnt personally let anyone near the cylinder head of my car without doing that test. cowboys..

Dye test was done but not over 2 or 3 weeks - more like 2 or 3 days. I reckon they just changed the cylinder head and crossed their fingers:rolleyes:

crosstownk

I'm bumping this as I'm hoping someone might have an answer......

I'm at my wits end with this car!!!

BrianD3

I see it's a turbo diesel. Does coolant circulate around or near the turbo for cooling or to assist cooling of the turbo etc.. A small leak in this area and you might get coolant boiling away very quickly and leaving little or no trace.

Also, 1 litre in 3000 km is not a lot. It's obviously something pretty small. Perhaps the pressure and compression tests that have been done are not sensitive or accurate enough to pick up such a small abnormality

crosstownk

BrianD3 wrote:

I see it's a turbo diesel. Does coolant circulate around or near the turbo for cooling or to assist cooling of the turbo etc.. A small leak in this area and you might get coolant boiling away very quickly and leaving little or no trace.

Also, 1 litre in 3000 km is not a lot. It's obviously something pretty small. Perhaps the pressure and compression tests that have been done are not sensitive or accurate enough to pick up such a small abnormality

Don't know if coolant circulates around the turbo or not - I don't think so. I also take you point that 1l per 3000km is not a lot but in reality coolant rarely needs to be topped up so this car is a bit odd in that respect.

I don't drive this car - it's a fleet car that I'm responsible for. I've sent it to a main VW dealer on 2 occasions and tbh they haven't a clue whats wrong with it. It's not that they are incompetent or anything but this small leak is hard to nail down. The driver (my customer) drives rally cars so he understands the difficulty in finding the leak and is also aware that he needs to keep an eye on the coolant. There are probably 40 other Golf TDIs on fleet and none need the coolant topped up like this one. The driver swears that he doesn't drive the car hard and tbh I believe him so it's not like is continually putting demands on the cooling system. I'm concerned that when the warranty runs out VW will kick it to touch (as they sometimes do) and I'll end up with a real headache trying to get them to cover the repairs.

I'm sure you'll agree this is a difficult one. I think another dye test is needed, but for 2-3 weeks as suggested earlier.

BrianD3

Tis a difficult one alright. This is one scenario where you'd probably prefer to see coolant gushing out somewhere

On the turbo, a quick google reveals that coolant is often used as well as or instead of oil to cool turbos in cars. Don't know what the story with the VAG TDi is though.

Also I found this page, haven't read it carefully but it may give you some ideas.
http://forums.tdiclub.com/showthread.php?t=133100

crosstownk

Thanks BrianD3! The symptoms on that link sound very similar - I need to determine if the Golf TDI uses the same EGR set up wrt coolant. I'll get this checked asap.

Hopefully it will put it to bed!! I'll let you know.

Thanks.

DROGBA1

crosstownk,just wondering did you get to bottom of your golf coolant problem.i have vw passat with similar problem.changed waterpump and thermistat 3 months ago but problem persists and pressurised it with 2 seperate mechanics,none finding leak.However coolant level still falling fairly rapidly.last mechanic checked every pipework on engine and said bone dry.he thinks maybe new waterpump gone also.it could be ok for a week and then suddenly drop,and last time it dropped on small journey into town(6 miles).i've been checking it every morning.one morning it was above previous nights level.Totally stumped.