Yet another coolant post......

[Dan 80]

OK, so got the Passat mot'd and started using her. The coolant is being a nightmare. It can deplete the full reservoir over night one night and the next only drop an inch or so.

The tank and cap was damp on the overflow underneath so I have replaced the tank and cap with a new item from GSF. Car is still losing coolant. Tell tale signs are that it still is coming out of the tank overflow underneath.

The little return pipe on tank pulses coolant back into the tank. Here is a video link: https://youtu.be/pRNpWYEXAVM

Does this indicate the water pump at fault? There doesn't seem to be any leaking from the flange at rear of the head. No steam or white smoke from the exhaust. Radiator was replaced 18months ago by myself (bought the car from a friend).
Heating is hit and miss, most likely due to losing coolant and drawing air into the system.

Not sure what else to try?

Compression test perhaps?

I'm waiting for the service history paperwork to confirm if the pump was replaced at the same time as the timing belt, about 3 years ago. Servicing was all done at the York VW dealership.

Car is a 2003 1.9tdi AWX.

Cheers.

Dan

[Col]

You have done the usual and easy stuff that I'd suggest doing however it might be worth another look at the radiator.

If there are no signs of visible leakage then sadly it is likely to be the head gasket.

[Dan 80]

Just to update.....

The coolant pump is at fault. Impeller is spinning around freely. Currently in the process of replacing the pump. Doing an hour or so each night after work.
Hopefully no head/block/gasket damage. Will find out once the pump is done.

After this, it's then on to tackle low power, poor mpg and an electrical issue. Lol.

Joys....


Dan

[bk.bas99]

Poor MPG can be cooling related. On mine the thermostat was only ever allowing the coolant temp to reach 81 degrees (according to VCDS). I replaced with a pattern one and it went up to 86 which threw me for a while, but eventually replaced it again with a genuine VW part and coolant now tops out at correct temp on VCDS, and gets there MUCH quicker than before so car must have been overfueling for quite a while on short trips. You can't really tell from the temp guage as it sits around the middle where it should be but difference of a few degrees won't show up