I assume the temp is high

You need to check that assumption. Measure the actual temperature at the top of the radiator (after a long run so t'stat is open and everything is up to temp) with an IR thermometer. Is it actually 110 degrees?

What engine do you have?

 

It’s the 2.0 tdi. I agree that the temp may not be correct as the header tank is not but not really hot if you know what I mean it’s easily touchable. I’m going to borrow an IR thermometer tomorrow and try what you have suggested. Could you tell me best place to take temp from?
I’m starting to think it’s an electrical sensor issue which may also explain the fan running??

 

I think ir thermometers work best if pointed at matt black areas.

 

On that engine, the only part of the coolant circuit that is isolated by the thermostat is the cooled return from the radiator to the water pump, so (for example) the temperature at the EGR cooler should be at around engine coolant temp at all times, whether the 'stat is open or not. The input to the internal heater matrix should be pretty close to full coolant temp too (it actually follows the EGR cooler).

I haven't looked at the pressure limits on the system, but TBH I would expect that at 110 degrees you would be getting boiling and coolant venting out of the pressure relief valve. Whether that's correct or not, you would expect the whole engine to be very hot. Mine has never exceeded 98 degrees that I can recall, and that was after at least an hour on the motorway in high ambient temps. So unless it's all pretty hot under the bonnet, I would be inclined to doubt the 110 degrees.

 

The engine bay doesn’t seem to be overly hot, I’ve had engines overheat before and this doesn’t really show any other symptoms, unless the fan was running I wouldn’t suspect a thing,

 

110 degrees is right at the top of the 'normal' range and you would certainly expect the cooling fan to be on at that point but it would normally take something like a very hot day and then being suddenly stuck in motorway traffic after a fast run/hills/towing to produce that. It's not something sustainable long term.

It sounds to me like the G62 coolant sensor is reporting high and therefore keeping the fans on. I know you did say that the temp sensor had been replaced but do you have any record of the full part number of the the sensor? Not sure how it is on the 2.0 engines but there will usually be two sensors on modern VW's. The G62 and the G83. If they replaced the G83, that reports the much cooler radiator outlet temperature and won't be the sensor that is showing your 110 degrees via OBD11/EOBD. So they could have simply replaced the wrong one.

 

110 degrees is right at the top of the 'normal' range and you would certainly expect the cooling fan to be on at that point but it would normally take something like a very hot day and then being suddenly stuck in motorway traffic after a fast run/hills/towing to produce that. It's not something sustainable long term.

It sounds to me like the G62 coolant sensor is reporting high and therefore keeping the fans on. I know you did say that the temp sensor had been replaced but do you have any record of the full part number of the the sensor? Not sure how it is on the 2.0 engines but there will usually be two sensors on modern VW's. The G62 and the G83. If they replaced the G83, that reports the much cooler radiator outlet temperature and won't be the sensor that is showing your 110 degrees via OBD11/EOBD. So they could have simply replaced the wrong one.

110 degrees is right at the top of the 'normal' range and you would certainly expect the cooling fan to be on at that point but it would normally take something like a very hot day and then being suddenly stuck in motorway traffic after a fast run/hills/towing to produce that. It's not something sustainable long term.

It sounds to me like the G62 coolant sensor is reporting high and therefore keeping the fans on. I know you did say that the temp sensor had been replaced but do you have any record of the full part number of the the sensor? Not sure how it is on the 2.0 engines but there will usually be two sensors on modern VW's. The G62 and the G83. If they replaced the G83, that reports the much cooler radiator outlet temperature and won't be the sensor that is showing your 110 degrees via OBD11/EOBD. So they could have simply replaced the wrong one.

110 degrees is right at the top of the 'normal' range and you would certainly expect the cooling fan to be on at that point but it would normally take something like a very hot day and then being suddenly stuck in motorway traffic after a fast run/hills/towing to produce that. It's not something sustainable long term.

It sounds to me like the G62 coolant sensor is reporting high and therefore keeping the fans on. I know you did say that the temp sensor had been replaced but do you have any record of the full part number of the the sensor? Not sure how it is on the 2.0 engines but there will usually be two sensors on modern VW's. The G62 and the G83. If they replaced the G83, that reports the much cooler radiator outlet temperature and won't be the sensor that is showing your 110 degrees via OBD11/EOBD. So they could have simply replaced the wrong one.

Hi T5 TDI, and thanks for your reply, very useful. I apologise if by me posting a question asking for confirmation of the 2 sensor possibility I only asked as you said “you were not sure how it is on the 2.0 engines” and that there would usually be 2 sensors on modern VW engines, this lead me to believe you were not 100% sure so I asked if anybody could confirm this regarding the 2.0 engine. I apologise is this seemed impolite as has been suggested. Apologise again and thanks for taking the time to reply. 👍🏼

 

That sounds possible I would be Interested if anybody could confirm that the 2.0 has 2 sensors as you suggest only I’ve searched the parts and can’t get a definitive answer. Hmmmmm

 

I don't usually take things posted online too personally, and although it was kind of Triffic to take slight umbrage on my account, I did qualify that statement as you mentioned. Starting a whole new thread was a bit unnecessary though..

Having a look around on the web I can't see any evidence that there are any other coolant sensors other than the standard two. Although the 2.0 cooling system is quite sophisticated. To confirm what is really going on with yours if you can get access to VCDS you could watch and make a log (record) of both coolant sensors live from cold. I did this with mine the other day and made a graph of the two sensors during warming up.

 

I don't usually take things posted online too personally, and although it was kind of Triffic to take slight umbrage on my account, I did qualify that statement as you mentioned. Starting a whole new thread was a bit unnecessary though..

I confess I wasn't tooo worried about your hurt feelings. My frustration with people suddenly starting a whole new thread without any apparent reason is that it loses the context of the original question - and then people have to take time asking questions to find out the context, and then the OP either has to explain or to refer back to the original thread, which wastes more time. It can also be unhelpful at a later date when someone with a similar problem tries to follow a thread - they have no way of knowing that it stops and restarts in a different thread.

I can confirm what you say - as far as I'm aware, there are only two.