Engine overheating warning?

[Coolguy@18]

Hi guys, hope you can help to see if you have come across this issue before?

 

We have a 2015 mk3 Octavia with the 2.0Tdi engine (CRMB) and every now and then when driving the car will hick up (like it's trying to go in limp mode for 1 sec) and a red warning will display for a sec (sometimes not long enough to read) stating please stop engine overheating!

 

Now the water pump has been replaced with the revised genuine pump, the coolant temp sensor has been replaced genuine.

 

There are no codes stored in the ECU.

 

With live data on the car such as:

Coolant temp

Rad temp

Oil temp

ECU temp

Intake temp

 

All are in spec and when  the warning displays there are no temperatures spikes!

 

Any one come across this?

 

Ryan

[Coolguy@18]

Also the temp gauge its self will rise to 90 and stay there, when I get the warning the gauge still stays at 90, if this helps.

[PetrolDave]

Is there maybe an air lock in the cooling system?

[Coolguy@18]

20 minutes ago, PetrolDave said:

Is there maybe an air lock in the cooling system?

Hi there, definitely no air lock in the system.

[Scout151]

Any faults logged in vcds with aggressive mode on also when is this happening during your driveing ?

[Coolguy@18]

2 minutes ago, Scout151 said:

Any faults logged in vcds with aggressive mode on also when is this happening during your driveing ?

Hi mate,

 

No faults logged in any ECU, I even had live data for EML warning and this will not change upon the overheating warning, dont think it is showing the error for long enough for it to light a code.

 

So strange??

 

I also looked on the wiring diagrams and I can only see one coolant temp sensor for this engine.

 

Seems like a software glitch?

 

It's strange when it happens the engine will lose all power for a second until light goes off?

[Scout151]

I would expect there is more in the Temp value yoused from the over all system as it has a chanrge cooler. Are you yousing vcds ? 

[Coolguy@18]

1 minute ago, Scout151 said:

I would expect there is more in the Temp value yoused from the over all system as it has a chanrge cooler. Are you yousing vcds ? 

Yep using a couple of high end diag software 1 being full VCDS.

 

The list of temp options I gave was just an idea but I had loaded up the charge cooler and again in spec and when fault happens no spike or change in temp??

[Scout151]

Very odd might be cude but have have you trued leaving battery disconnected for a while . I remover having a mk 4 Mondeo with a odd glitch with tpms . Ids computer wouldn’t even clear the fault left disconnected over night and it was perfect when we came back in morning 

[Coolguy@18]

Just now, Scout151 said:

Very odd might be cude but have have you trued leaving battery disconnected for a while . I remover having a mk 4 Mondeo with a odd glitch with tpms . Ids computer wouldn’t even clear the fault left disconnected over night and it was perfect when we came back in morning 

Yep, even done a static drain but no different.

 

I would like to think I am missing a intermittent temp sensor some where but think I have got them all.

 

The red warning is for the engine cooling system overheating so you would think coolant temp.

 

There is no codes for any temp senor faults though?

[Scout151]

Silica bag ok and heating ok ? Or has it burst in the past as the aux pumps get clogged up

[Coolguy@18]

Just now, Scout151 said:

Silica bag ok and heating ok ? Or has it burst in the past as the aux pumps get clogged up

Nope the common bag issue is fine, coolant system has been flushed as well to make sure.

 

This really seems like an electronic issue to me..

[Scout151]

Was original fault for the the actuator on the pump ? 

[Coolguy@18]

1 minute ago, Scout151 said:

Was original fault for the the actuator on the pump ? 

There was no original fault so to speak.

 

All started with this red warning (engine overheating) and engine stutter at same time as warning.

 

We replace the pump as it was a revised unit and new temp sensor.

 

This fault has started since any part replacement but has but has not fixed the intermittent issue and with no code as well it's hard to pin point it..

[Superhero572]

My Octavia (MY2015 1,6 TDI 4x4) had similar issue 2018 fall and 2019 summer.

 

2018 fall; Happened once, i was driving to work. If i increased speed over 90kmh coolant temperature immediately reached it’s maximum.. And when speed dropped under 90kmh temperature fell back to normal... Quick car restart fixed it. There was no error codes stored when i checked.

 

2019 summer; several times in few weeks i got temperature warning + check coolant. I always checked coolant and it was OK, no leaks etc. Restarting car fixed problem. No error codes stored.

Car was ok for month, so i thought it was just software bug again.. Just like car says sometimes i need to change ”front right side light” although it’s working just fine  

2019 fall waterpump failed and Octavia needed towing to shop 1 year or 40 000km before normal water pump+timing belt change interval (6 years, 210 000km). 

After that it have been working fine.

 

 

 

My friend have MY14 2.0 octavia and he changed water pump+timing belt 2019 summer too, but just after christmas car was leaking coolant again. It was leaking from water pump and coolant thermostat —> skoda service said that thermostat leaking is known problem with 2.0 octavia.

 

 

 

 

[Coolguy@18]

So far I have tried live data on.

 

Oil temp.

Coolant block temp.

Rad out let temp.

Intake temp.

Intake charge temp.

Alt temp.

Turbo temp.

Exhaust up temp.

Exhaust down temp.

ECU temp.

 

Nothing will change upon this fault.

 

Do you know of any other sensor that can cause this message?

[xpower]

There are 2 Skoda TSB’s for engine overheating / coolant warning etc.

 

when you get the engine overheating warning is it accompanied by a coolant low level warning?

The 2 TSB’s are:

1) 2046852/7

The coolant level light illuminates, engine overheat message

 

2) 2039483/9

High temperature reading, coolant light illuminates

(this one is the updated water pump fix)

 

Edited 12 January, 2020 by xpower

[Coolguy@18]

7 hours ago, xpower said:

There are 2 Skoda TSB’s for engine overheating / coolant warning etc.

 

when you get the engine overheating warning is it accompanied by a coolant low level warning?

The 2 TSB’s are:

1) 2046852/7

The coolant level light illuminates, engine overheat message

 

2) 2039483/9

High temperature reading, coolant light illuminates

(this one is the updated water pump fix)

 

 

Hi there, thank you for the reply.

 

There is no low coolant warning, temp gauge is at 90. The red warning will show on the cluster for about 1 sec with loss of power until light goes out. The warning states engine over heating.

 

If I unplug the plug on the coolant bottle I will get a red warning on the cluster but it's a different message, this will state Check Coolant, so I know it's not a low level issue.

 

TSB 1 - Dont think this is my issue as it's not a level issue.

 

TSB 2 - Dont think this is my issue as I think people report of the warning along with the temp gauge going past 90. Mine will display message but temp gauge at 90 plus a new revised pump has been fitted.

 

The coolant system as also been bleed via diag machine etc

 

Any ideas??

[DCam]

Hi Ryan, I'm having the exact same problem with my 2016 octavia 2.0 litre tdi. I've had all sensors, thermostat, waterpump changed still no affect.

Did you find out what was causing the problem?

[Ahsan]

you might need to change the coolant box. i had to changed mine because of overheating box was leaking coolants sp i had to replace the box.

[DCam]

Thanks for your post bud, I haven't got any leaks though. I'm sure it's an electric problem as the warning light comes on sometimes

when I start the engine and then randomly. I seen a similar post from 2017 which makes me wonder if it's a common fault.

[TheClient]

Was the other post, a solenoid fault so the car is actually overheating in some location in the cooling system or just an electrical gremlin?  I guess a place to start is find where all the coolant temp sensors are and test them electrically if you can.

[DCam]

Thanks for the reply. The other car had the same problem. An erratic engine overheating warning light. I've had sensors, thermostat

even waterpump changed so I think it's an electrical problem. Going to see an auto spark on Thursday so here's hoping.

[CapitalRibs]

Similar issue here to 2.0 tdi 2014 Octavia VRS. Auxiliary pump changed in January this year (2022) 65k on clock and full dealer service history.

 

On a dual carriage way hit 85mph after 30 minutes of town driving. Temp needle climbed up just under the red. Warning symbol on dash so pulled over on the grass verge, waited, drove car to local airfield no sign of excess heat from engine... Car drove OK after. Booked it in with the garage that did the pump replacement they could find no codes logged and couldn't replicate the issue. 

 

All this after leaving my car on the drive over the jubilee weekend! 

 

I had a skoda data plug in the odb port. The garage thinks I should leave it out (it's useless anyway)... But reading the hunch that it could be electrical... One thing I've noticed recently is that my interior light doesn't come on when we open the doors. If I give the switch a hard tap they flash intermittently... Probably just a dodgy switch and not connected but anyway... 

 

Would be great to hear if the auto sparky has found anything... 

 

 

[DCam]

Hi there. He did, the problem was a couple of wires were too close to the engine manifold and this was causing false signals been sent to the ecu. Hope this helps