Cooling System

**Clinterous** · 12-01-2012,03:03 PM

Hello individuals.

My 2003 1.9tdi awx is loosing coolant. I cannot see any external leaks, but me fearing a head gasket leak has asked a local garage to have a look.

Apparently, the coolant is not circulating, so they expect a faulty water pump. If the water pump is at fault, where would the coolant be going? Also, the car is not showing any overheating symptoms and the heating still works, which I would expect to be happening if the pump was faulty.

Any extra ideas much appreciated.

**NickPicks** · 12-01-2012,03:31 PM

it depends on what they mean by faulty. If the fault is that the impeller vanes have broken, then it won't be leaking, but will not circulate water. If the car then overheats, the pressure will force water out through the expansion bottle cap. If the water pump is leaking, then you'd see water drips / coolant residue below it or around the pulley.

How have they diagnosed lack of circulation? I can't see through the hoses on mine to see if the water is circulating. Do you trust your local garage, or could they be guessing it's the water pump?

**portovechios** · 12-01-2012,04:47 PM

The pump can be failing to varying degrees

I found mine used to heat the cab at low speed but slip at highspeed and blow cold air. This time of the year the pump may be coping to varying degree despite the fact its knackered

It can come off the shaft and just slip

Either way it sounds like a new pump needed

**portovechios** · 12-01-2012,04:49 PM

Sooner rather than later, if your header tank is blowing coolant its probably overheating

Is your top hose hot and bottom hose warmish after 2 miles?

**Clinterous** · 12-01-2012,05:36 PM

The header tank hasn't been pressurised at all.

Collecting the car shortly; I hope they investigated more than just feeling that the bottom of the radiator was cold, when the top was hot for their hours labour charge!

**Col** · 12-01-2012,08:09 PM

I've just been through this exact problem on my AWX'd passat but without water loss.

It was the water pump.

As for top and bottom hoses getting hot, you'll be lucky to feel any heat in the bottom hose at this time of year even after running for 30+ miles. The you should feel heat in the top hose fairly soon though.

**portovechios** · 12-01-2012,08:36 PM

Hot top hose and you pumps working, no garentee it's working efficiently though

Garage will know that, do you trust them?

Sadly if you can't do it yourself it's not a cheap job

**portovechios** · 12-01-2012,08:42 PM

HG usually shows emulsified oil (creamy colour froth) at the oil filler dependent on which direction the gasket has blown of course

The garage can presurize the cooling system and look for leaks.

How much you losing?

**Clinterous** · 12-01-2012,10:32 PM

Many thanks for the input.

Difficult to comment on how much I'm losing accurately as I've not measured yet. My daily commute (there and back) is 130 miles, at an average of 65mph, and I reckon I'm losing 350ml - 500ml a day.

The oil looks clear of water contamination.

This is the first time at this particular garage today. Gut feeling is I'm not impressed.

I've had look this evening with a torch and can see dampness/moisture on top of the gearbox, driver side behind engine. I can't work out if that is spilt oil from the filler cap, or is coolant - too dark and my arm wouldn't fit into the gap. I'll have to wait to weekend now for a better look in daylight and more time to take the intercooler pipe out of the way.

The cambelt is due for a change, but I'm hesistant of cracking on with that if it turns out the HG is starting to go.