Audi A6 heating up

zamo27

My 2003 audi a 6 1.9tdi was reaching nearly 100 degrees and I got the thermostat changed as it was faulty now it's guzzling coolant and still heating up occasionally when I hit high revs coming down a slip road onto a motor way
What could it be
Radiator? Water pump? Or head gasket on the way out?

Tropheus

Firstly check the fluid level? Is it noticeably losing fluid? If so, that would point to either a ruptured hose or the water pump.

The radiator is also worth checking for leaks, but less likely.

biko

Do the fans work?

Wheelnut

zamo27 wrote: »

...and still heating up occasionally when I hit high revs coming down a slip road onto a motor way...

It's pretty drastic if it's heating up in the length of a slip road (I presume you mean "over heating"). Sounds like the water pump.

Some of those water pumps had plastic impellers that could break off so you need to get one with metal impellers.

zamo27

biko wrote: »

Do the fans work?

Fans work and on a motorway doing 120 or a max of 80miles an hour the fan is not whats cooling the engine, I think.

I'm toping up coolant every few days depending on journeys or if it overheated
So is it all pointing towards water pump?

biko

Yeah, once you reach a certain speed the flowing air is enough to cool engine.

Actually I just realised you said it was using a lot of coolant.
Have you identified a leak in the radiator/expansion tank?
Is there gunk inside the oil cap/dipstick?
Smoke on startup?
Discoloured coolant?

If the water pump didn't drive the coolant around at all then the car should overheat much more often than occasionally.

zamo27

biko wrote: »

Yeah, once you reach a certain speed the flowing air is enough to cool engine.

Actually I just realised you said it was using a lot of coolant.
Have you identified a leak in the radiator/expansion tank?
Is there gunk inside the oil cap/dipstick?
Smoke on startup?
Discoloured coolant?

If the water pump didn't drive the coolant around at all then the car should overheat much more often than occasionally.

I can't spot leaks anywhere and the dip stick is clean and oil level is ok and no gunk under the oil cap.
It does fire a lot of white smoke on start up especially first thing in the morning
Thank you Biko for your help you guide me a bit more on this?

Tropheus

It could be a leaking hose. I had that problem on my allroad. As they get older, the hoses become brittle and can leak.

biko

zamo27 wrote: »

It does fire a lot of white smoke on start up especially first thing in the morning

At this time of year that's not unusual, mine does too. Often it's just condensation that burns off after a few mins.
If smoke is anything but steam (wispy and vapour-like) then it could be a problem.

If you can find someone who still does pressure testing of cooling systems they may be able to help you find if it's just a leak. I know old BMWs have a brittle expansion tank that is prone to hairline cracks and let out the coolant that way.

Even an old bad radiator cap can release coolant steam over time too.

Did it start to lose coolant more after the thermostat change?
Is it a steady process over several days?

zamo27

biko wrote: »

At this time of year that's not unusual, mine does too. Often it's just condensation that burns off after a few mins.
If smoke is anything but steam (wispy and vapour-like) then it could be a problem.

If you can find someone who still does pressure testing of cooling systems they may be able to help you find if it's just a leak. I know old BMWs have a brittle expansion tank that is prone to hairline cracks and let out the coolant that way.

Even an old bad radiator cap can release coolant steam over time too.

Did it start to lose coolant more after the thermostat change?
Is it a steady process over several days?

Yesterday I checked the coolant and the reservoir was 1cm below the minimum. Top up and off I went to Dublin, drove around and back to Kildare town and this morning same agsin, 1 cm below the level but no overheat whatsoever. I did drive like my wide in fairness!