Tonight on my way home from work engine suddenly overheated then dropped back down to normal temp, not had this issue before and did a couple of long drives over the summer. Checked coolant level an that’s as it should be and can’t see and leaks.  Anyone had this issue before or any idea what it could be? 
 

thanks in advance 

I had similar on a passat 20tdi at about 80k, it was the water pump, mine let me down in the middle of the night, after a few times with temp going up but then returning to normal, I think a moving collar sticks shut but sometimes returns to normal.....until it doesn't 😉

👍 Cars booked in the garage tomorrow so see what they say. Warranty ran out two weeks ago 🙄

Sounds like the water pump giving you its first warning.  There are two stages to water pump failure.  The first one is the over heating, then back to normal.  You might get 2 or 3 of these if you are lucky.  Then the pump will suddenly fail (second stage) - usually by completely distroying itself internally or by breaching the seal for the pump.

👍 Cars booked in the garage tomorrow so see what they say. Warranty ran out two weeks ago 🙄

Update

cars been in the garage they said they can’t find any faults on it and have test drove it and can’t get it to over heat. Said it could have been an air lock . Stuck as what to do now. 

Where did this mysterious air lock come from?

If you have not done any maintenance on the cooling system, then there would have to be a problem to cause an air lock?

 

 

Air locks tend to be the result of a problem, failing coolant pressure cap, coolant leak, not being bled properly.... head gasket allowing combustion gas into the system etc.

 

What engine do you have? Some of the TDI range suffer from water pump failure and this is an early symptom. 

 

I guess all you can do is keep an eye on it and see if the same issue happens again.

Edited 6 October, 20214 yr by MATT0693

👍 Cars booked in the garage tomorrow so see what they say. Warranty ran out two weeks ago 🙄

 

1.6 tdi green line, like you say will have to keep an eye on it 👍

It will be the water pump going south. Sounds like a lazy dealer who hasn't read the CANBUS network faults or done a decent investigation.

13 hours ago, varaderoguy said:

It will be the water pump going south. Sounds like a lazy dealer who hasn't read the CANBUS network faults or done a decent investigation.

Not sure this kind of problem should pop up a warning on the logfile, since it appears pure ‘mechanical’ problem.

But... May be I´am wrong. It depends on how fine / clever the health monitoring system is.

Not from the pump agreed but from sensors in the coolant system you will get warnings and lack of flow of coolant etc. Sorry that's what I meant.

Have just bought a used 1.6D and on the way home from collecting it had the overheat symptoms. Took it to my local independent yesterday who couldn't find fault (via fault codes) but have said it's likely to be the sleeved water pump issue. It's booked in for new pump and cam belt next week. In the meantime it's careful, short trips for me.

@Jonnoh79 How many miles has it done?  Could well be worth getting the pump and cambelt done as a precaution unless you are on low miles.  If indeed it is low miles then a proper look by a dealer should turn up a fault and an offer of paying some of the bill as you are only just out of warranty.