Could do with some advice guys, on a long motorway run from Scotland to Cornwall, car has thrown up a coolant warning after about 3hrs constant motorway cruising, temp gauge barely off the 50 mark, no cabin heat and rad fans running while driving.

 

Noticed that starting the journey the car was reluctant to start for a few seconds/Two turns of the key almost as if starter kept turning for a second or so after engine on and MPG on the journey had been very low.

 

Pulled over and I have lost coolant from the expansion tank, barely any in it and it's clearly been ejecting it from the overflow. Topped up with water and nursed it to overnight hotel.

 

Had tons of issuer earlier in the year with a leaking water pump, poor cold idle then a multitude of coolant sensor issues. Had all new water pump, timing chain all done due to a correlation error, every coolant sensor changed, cabin water pump fault changed, new silicon tbag free expansion tank all changed in January. Car seemed to have been running spot on until today.

 

Anyone got any ideas?? It's a 64plate 2.0TSI MK3 EA888 Octavia VRS on 116k.

 

Skoda Assist due out first thing.

Edited 18 May, 20242 yr by TeebsVRS

30 minutes ago, TeebsVRS said:

Could do with some advice guys, on a long motorway run from Scotland to Cornwall, car has thrown up a coolant warning after about 3hrs constant motorway cruising, temp gauge barely off the 50 mark, no cabin heat and rad fans running while driving.

 

Noticed that starting the journey the car was reluctant to start for a few seconds/Two turns of the key almost as if starter kept turning for a second or so after engine on and MPG on the journey had been very low.

 

Pulled over and I have lost coolant from the expansion tank, barely any in it and it's clearly been ejecting it from the overflow. Topped up with water and nursed it to overnight hotel.

 

Had tons of issuer earlier in the year with a leaking water pump, poor cold idle then a multitude of coolant sensor issues. Had all new water pump, timing chain all done due to a correlation error, every coolant sensor changed, cabin water pump fault changed, new silicon tbag free expansion tank all changed in January. Car seemed to have been running spot on until today.

 

Anyone got any ideas?? It's a 64plate 2.0TSI MK3 EA888 Octavia VRS on 116k.

 

Skoda Assist due out first thing.

Very likely electromechanical thermostat failure. If the car is on it's first at 10 years 116k that would be amazing. More likely this will be the second replacement.

Hi brand new water pump/stat unit fitted back in December

During this long motorway run, what was the oil temperature showing while the coolant gauge was displaying low? Was the coolant level correct before starting the trip?

Edited 18 May, 20242 yr by Warrior193
correction

Why the water pump and stat unit last December?   Same reason as now, or a visible leak then?

2 hours ago, Ootohere said:

Why the water pump and stat unit last December?   Same reason as now, or a visible leak then?

Visible leak back then

2 hours ago, Warrior193 said:

During this long motorway run, what was the oil temperature showing while the coolant gauge was displaying low? Was the coolant level correct before starting the trip?

 

Maybe a touch high was about 112 at times, after I stopped and topped up the coolant and nursed it to the hotel it was under 70 degrees.

Am getting recovered home VW assist reckon there is no/restricted flow of coolant as bottom rad pipe is cold.

Different car, 1.4tsi, but identical symptoms and it required a new water pump.

Rather surprised that a probably overheating engine was indicating low coolant temperature - suggests that temp sensors may not be located in ideal position.   

9 minutes ago, Warrior193 said:

Rather surprised that a probably overheating engine was indicating low coolant temperature - suggests that temp sensors may not be located in ideal position.   

That's my concern too, no idea what the true issue is yet. VW Assist guy took temp readings after 10mins idle definitely cool at bottom hose.

1 hour ago, TeebsVRS said:

That's my concern too, no idea what the true issue is yet. VW Assist guy took temp readings after 10mins idle definitely cool at bottom hose.

To me the cold rad outlet indicates a faulty thermostat. Or a blockage. But together with lost coolant.?  So far as temp sensors there’s 2. One on the rad outlet, one on the engine head, rhs I think. Obd11 or vcds allow you to monitor both. A complete thermostat failure would normally also record a dtc.  Ie log a fault…

1 hour ago, Warrior193 said:

Rather surprised that a probably overheating engine was indicating low coolant temperature - suggests that temp sensors may not be located in ideal position.   

I had that on a car over 40 years ago, the problem was that no coolant was reaching the temp sensors because of no water flow - if there's no flow then it really makes little difference where the temp sensor is!

The system is definitely pressurising as well, could see the expansion tank starting to fill up higher even after just a 10-15min idle.

1 hour ago, PetrolDave said:

I had that on a car over 40 years ago, the problem was that no coolant was reaching the temp sensors because of no water flow - if there's no flow then it really makes little difference where the temp sensor is!

Yep. Remember driving in a mates dad's range rover 4.2l v8. In the 1990s. Rad burst. Steam, overheating but....  temperature gauge was dropping... which resulted in an argument, "debate" with the owner drivers son!!!  He didn't want to listen to the suggestion to stop and turn off, initially!! 

Air lock?

 

Expansion tank cap faulty?

Edited 18 May, 20242 yr by Stonekeeper

On 18/05/2024 at 16:47, Stonekeeper said:

Air lock?

 

Expansion tank cap faulty?

Air lock is a possibly. But now, after 10 years? If no recent coolant work,  I'd say very unlikely... haven't heard any updates from op... 

1 hour ago, TheClient said:

Air lock is a possibly. But now, after 10 years? If no recent coolant work,  I'd say very unlikely... haven't heard any updates from op... 

 

I was thinking of the comment

"Pulled over and I have lost coolant from the expansion tank, barely any in it and it's clearly been ejecting it from the overflow. Topped up with water and nursed it to overnight hotel."

 

A weak cap can stop the pressure being maintained and allow overflow

 

OP not responded since Saturday so it must be sorted?