2.0 BiTDi Getting Hot?

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MondeoMan1981

Original Poster:

2,407 posts

190 months

Friday 15th July 2022
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Have a 2018 Arteon BiTDI 240. 47k on clock.

Drove to shops earlier and then home 2-3 miles each way. Spirited legal drive, aircon on and normal drive mode.

Noticed at traffic lights half a mile from home that the temp display needle was approaching the red! Never really seen it drift from just above 90. Turned aircon off and by the time I got home half a mile down the road, needle had moved down a sector. Of course the fan was on and when I turned off at home the fan remained on for a short while at a reduced speed before turning off.

Levels on the tank and colour look good.

Am I looking at an issue? I know pumps on TDIs 2017ish have problems....or maybe just the car trying a regen?

Thoughts etc welcome.

Ironically the car is going to VW on Monday for MOT.

Insert Coin

1,965 posts

50 months

Friday 15th July 2022
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I’ve got the 204 BiTDi on my T6 which I assume is similar, I never see my temp gauge move even when doing a re-gen or towing my caravan.

On a slog my oil temps go up to 115ish, but water temp never varies.

I’d get it checked, especially in this weather.


Tony1963

5,331 posts

169 months

Saturday 16th July 2022
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Sounds like the water pump has died. Let it cool down completely, bonnet open, cap of expansion bottle, start the engine. Does it look like coolant is flowing/bubbling? Turn the engine off.

Sheepshanks

35,045 posts

126 months

Saturday 16th July 2022
quotequote all
The water temp gauge isn't linear - it's driven by the ECU and it stays rock solid at 90 because the ECU is outputting "OK". If it goes above that the ECU is telling it there's something wrong.

Could be the switchable water pump isn't switching either at all, or fast enough. Or some other cooling system issue - IIRC there's three cooling circuits with various sensors and controls.

MondeoMan1981

Original Poster:

2,407 posts

190 months

Saturday 16th July 2022
quotequote all
Thanks all.

Car is under approved used warranty and was ironically, booked in for MOT on Monday. Spoken to dealer this morning when they called to confirm Monday's appt and they will take a look.

Coolant levels and colour were good.

Google suggests VAG waterpumps are not the most reliable.

CarCrazyDad

4,280 posts

42 months

Saturday 16th July 2022
quotequote all
Sheepshanks said:
The water temp gauge isn't linear - it's driven by the ECU and it stays rock solid at 90 because the ECU is outputting "OK". If it goes above that the ECU is telling it there's something wrong.

Could be the switchable water pump isn't switching either at all, or fast enough. Or some other cooling system issue - IIRC there's three cooling circuits with various sensors and controls.
It will not move off "90" until around 107c which is far too hot for those vehicles - needs investigation, as it's not normal and shouldn't happen , hopefully the warranty is good. My memory of VW warranty is less than pleasant although that was over a decade ago

Alex Z

1,515 posts

83 months

Saturday 16th July 2022
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On slightly older 2.0TDIs, they used to use a plastic impeller in the water pump that would sometimes stick, causing just the symptoms you describe. I expect the dealer will be very familiar with the problem.

MondeoMan1981

Original Poster:

2,407 posts

190 months

Monday 18th July 2022
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And of course on the drive to the dealer it behaves impeccably barring a hiss when turning the aircon on.

Tony1963

5,331 posts

169 months

Monday 18th July 2022
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MondeoMan1981 said:
And of course on the drive to the dealer it behaves impeccably barring a hiss when turning the aircon on.
How far was that drive? Did the dash gauge reach ‘normal’?

MondeoMan1981

Original Poster:

2,407 posts

190 months

Saturday 6th August 2022
quotequote all
And after 2 weeks of perfect running the temp gauge went over the 90 today. And it kept going til it hit the red and I got a warning to stop about 3 miles from home.

So I did. And after that I set off again after turning back and it climbed again so I stopped again. After the second break the temp actually came back down, like last time this happened - by which time I was back home anyway. Had a look under the bonnet all look intact, fluids looked fine in level/colour.

Ironically my dealer's phone lines were broken so I couldn't book it in but I'll do that Monday and hopefully the codes are stored!

W12PRR

25 posts

138 months

Sunday 7th August 2022
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Used to have a Polo with a knackered thermostat that behaved in the same way.
Soon as you moved off from stop it would start to cool off again once there was some airflow across the radiator.

Might be worth suggesting to the workshop staff as its not the sort of thing that pops up as a code. Dealer workshops seem to just follow what the laptop says nowadays.

CarCrazyDad

4,280 posts

42 months

Monday 8th August 2022
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MondeoMan1981 said:
And after 2 weeks of perfect running the temp gauge went over the 90 today. And it kept going til it hit the red and I got a warning to stop about 3 miles from home.

So I did. And after that I set off again after turning back and it climbed again so I stopped again. After the second break the temp actually came back down, like last time this happened - by which time I was back home anyway. Had a look under the bonnet all look intact, fluids looked fine in level/colour.

Ironically my dealer's phone lines were broken so I couldn't book it in but I'll do that Monday and hopefully the codes are stored!
My personal opinion would be to try to film the dash when the car is doing it
I appreciate this may be illegal at times but you need to "capture" the issue

The problem will either be faulty temp sensor, thermostat or fan

Does the fan spin with AC on and when car is hot / idling etc?

MondeoMan1981

Original Poster:

2,407 posts

190 months

Tuesday 9th August 2022
quotequote all
CarCrazyDad said:
My personal opinion would be to try to film the dash when the car is doing it
I appreciate this may be illegal at times but you need to "capture" the issue

The problem will either be faulty temp sensor, thermostat or fan

Does the fan spin with AC on and when car is hot / idling etc?
Mrs and 10 month old child were in the car so I got her to picture the dash initially as it climbed above 90 and then when the warning appeared when I pulled over.

Fan is working.

Booked into dealer who could see me soonest, in a week's time, no courtesy car. Are they really all that busy!

MondeoMan1981

Original Poster:

2,407 posts

190 months

Monday 15th August 2022
quotequote all
Just to close off this post effectively and help anyone searching online with the same problem.

Water pump seizure diagnosed this morning.

New part and labour covered under warranty. Workshop manager called to ask if I wanted a new cambelt fitted while it was off anyway - yes absolutely. Done for cost of part only.

Car back tomorrow.

Deerfoot

4,980 posts

191 months

Monday 15th August 2022
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A result with the cambelt.

MondeoMan1981

Original Poster:

2,407 posts

190 months

Monday 15th August 2022
quotequote all
Deerfoot said:
A result with the cambelt.
£789 for fixed price cambelt and water pump.....massive saving....

Just over £200 for what would have been due next May anyway!

In true PH fashion guaranteed I'll sell it now

CarCrazyDad

4,280 posts

42 months

Tuesday 16th August 2022
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MondeoMan1981 said:
£789 for fixed price cambelt and water pump.....massive saving....

Just over £200 for what would have been due next May anyway!

In true PH fashion guaranteed I'll sell it now
Costs £400 at a good independant! Mental prices.

Glad the car is working (Hopefully!)

Sheepshanks

35,045 posts

126 months

Tuesday 16th August 2022
quotequote all
CarCrazyDad said:
MondeoMan1981 said:
£789 for fixed price cambelt and water pump.....massive saving....

Just over £200 for what would have been due next May anyway!

In true PH fashion guaranteed I'll sell it now
Costs £400 at a good independant! Mental prices.

Glad the car is working (Hopefully!)
The switchable pump bumps the cost up a bit - dealer charged £499 on wife's Tiguan a couple of years ago (after they'd quoted the then fixed price of £549. I tried the two highly regarded local indies and was put off as they both hummed and harred and said £400ish and I know one of them always indicates prices ex-VAT.

VW have whacked up the prices of all the maintenance items - I think it's off the back of their All In package, to get on it you really need to have had all those items done, and once your're on the package you're kind of obliged to get them done as they come up. They can pitch it that the cost is more reasonable as the service and MOT is "free" on the day.