1.4 coolant temp light

[Ollie86rn]

Hi all,

After much deliberation i decided to get a 2014 1.4 leon st which all seemed great on the way back home but yesterday i went out 5mins up the road and the coolant temp light came on. The engine definitely wasnt up to temp so wasnt concerned with overheating but watching the guage it varied rapidly from 90 -120.

There doesnt appear to be any leaks and when i undid the cap this morning, the pressure in the system released and the level was just above max.

I have tried looking in the forum but cannot find anything specific. Any ideas if this is a sensor issue or something else.

Thanks

 

[SuperV8]

I think first off you need to plug it in to read any diagnostic fault codes - sounds like a sensor or wiring to me?

 

[Ollie86rn]

Will need to take it to a garage in that case. Biggest concern is a head gasket failure but it has only done 57k miles.

It also seems that just before the coolant temp increase, the cabin heating goes cold so not sure if it is linked to the heater matrix.

Can the coolant be pressuried by anything else other that engine gas (ignoring temperaturefor now)? Heater matrix/water pump etc?

 

[SuperV8]

Will need to take it to a garage in that case. Biggest concern is a head gasket failure but it has only done 57k miles.

It also seems that just before the coolant temp increase, the cabin heating goes cold so not sure if it is linked to the heater matrix.

Can the coolant be pressuried by anything else other that engine gas (ignoring temperaturefor now)? Heater matrix/water pump etc?

The 1.4TSI has a water to air charger cooler so I suppose if that had an internal leak - high pressure air could pressurise your coolant.

Do you have any of the classic HGF symptoms? mayonnaise on your oil filler cap? white smoke out your exhaust?

Did you buy it from a garage? If yes I would be going back and telling them to sort.

 

[Ollie86rn]

The 1.4TSI has a water to air charger cooler so I suppose if that had an internal leak - high pressure air could pressurise your coolant.

Do you have any of the classic HGF symptoms? mayonnaise on your oil filler cap? white smoke out your exhaust?

Did you buy it from a garage? If yes I would be going back and telling them to sort.

Ah i didnt know that. Nothing in the oil that i can see and only a bit of smoke when its cold but i need to check this after a longer run.

 

[SuperV8]

The 1.4TSI can have a 'common' thermostat housing leak which would explain your heater going cold - but not the pressurised coolant system found in the morning on a cold engine?

 

[SuperV8]

Also looks like the 1.4TSI EA211 has a water cooled turbo - so another possible source for pressurising the coolant system?

 

[Ollie86rn]

Also looks like the 1.4TSI EA211 has a water cooled turbo - so another possible source for pressurising the coolant system?

Thats great thanks. I have had to book it into the garage as cannot see/find anything obvious and need it back on the road fairly quick.

Thought the silicant pack was another issue for coolant blockage but didnt think mine had it, certainly no stamps on the expansion bottle

 

[Ollie86rn]

Thought I would update this thread to see if anyone can shed some more light on my issue.

The car has been in the garage for 3 weeks now and still no closer to fixing the problem. The main issues are the coolant is being pressurised and overheats primarily when under load and the internal cabin heating becomes cold. So far work done:

• Heater matrix (non genuine) has been replaced
• Sniff test the coolant (no exhaust gases)
• Timing was slightly out so adjusted
• External pressure test the coolant to 1.5 bar to see if it is leaking onto the pistons - It is not

Previously a garage has fitted a skoda water pump which although should be compatible may also be a problem. If this does not solve the fault then potentially they are looking to take the head off - expensive job!

Has anyone had any similar issues to this or have any other ideas where the fault may be? The engine is the 1.4 (150) CZEA so I am aware there is a Charge coolant circuit to the turbo but don't know if this can cause the pressure issue.

HELP!

 

[Yern]

Issue similar (non Seat) I experienced some years ago was found to be a radiator issue. Radiator and coolant replaced.

 

[Ollie86rn]

Issue similar (non Seat) I experienced some years ago was found to be a radiator issue. Radiator and coolant replaced.

What was wrong with the radiator?

 

[RUM4MO]

Having a "Skoda" water pump should be okay as Skoda and others shared this engine, and it would have been built in a Skoda engine plant.

I'm sure that your garage know that these cars have a few issues, like the thermostat housing issues and they will have an electric charge cooler circuit pump. Vacuum backfilling seems to be the easy way to get rid of any trapped air in the system, and trapped air could be why it is ejecting coolant - or am I wrong in assuming that coolant is being ejected from the coolant reservoir, that needs to be worked if that is where the coolant is going.

 

[Ollie86rn]

Having a "Skoda" water pump should be okay as Skoda and others shared this engine, and it would have been built in a Skoda engine plant.

I'm sure that your garage know that these cars have a few issues, like the thermostat housing issues and they will have an electric charge cooler circuit pump. Vacuum backfilling seems to be the easy way to get rid of any trapped air in the system, and trapped air could be why it is ejecting coolant - or am I wrong in assuming that coolant is being ejected from the coolant reservoir, that needs to be worked if that is where the coolant is going.

There is no loss of coolant. Essetially after a drive, inspecting the expansion tank it would seem the coolant is low. If leaving it to cool down it would still indicate low however if you remove the cap, the pressure releases and the coolant flows back into the tank showing the correct level. There is no coolant in the oil either but no idea where it could be trapped, there is obviously a restriction somewhere!

 

[RUM4MO]

Without examining the cooling system diagrams, I'm sure that there are some one way valves so that only the intended flow route of coolant is maintained at all times, though I'd be surprised if they were "efficient" enough to stop pressures equalising after the system had cooled down - given enough time - unless one/some of them are faulty.

 

[SuperV8]

There is no loss of coolant. Essetially after a drive, inspecting the expansion tank it would seem the coolant is low. If leaving it to cool down it would still indicate low however if you remove the cap, the pressure releases and the coolant flows back into the tank showing the correct level. There is no coolant in the oil either but no idea where it could be trapped, there is obviously a restriction somewhere!

There are several versions of the coolant pump for the 1.4 -
Number 7 is a coolant regulator - again there are a couple of versions of this.
What is the exact number of the water pump they fitted?
If you IM me your reg I can tell you the correct one for your car.

 

[Ollie86rn]

Just sent you a message. Waiting to hear back on the water pump part number fitted

Without examining the cooling system diagrams, I'm sure that there are some one way valves so that only the intended flow route of coolant is maintained at all times, though I'd be surprised if they were "efficient" enough to stop pressures equalising after the system had cooled down - given enough time - unless one/some of them are faulty.

I dont have any system diagrams to look at but I know there are some restrictors and one way valves that may be an issue. The charge system is also an area I know very little about and whether the water cooled turbo could also cause pressure issues. I would expect some performance issues with the engine if this was true but the engine has been running absolutely find apart from the temp increase.

 

[Yern]

What was wrong with the radiator?

Must have been 'blocked' (poor water circulation). Suppose you could try a reverse flush see if it helped?

 

[SuperV8]

Just sent you a message. Waiting to hear back on the water pump part number fitted

I dont have any system diagrams to look at but I know there are some restrictors and one way valves that may be an issue. The charge system is also an area I know very little about and whether the water cooled turbo could also cause pressure issues. I would expect some performance issues with the engine if this was true but the engine has been running absolutely find apart from the temp increase.

I replied to your IM;

Did this issue happen before they fitted the water pump? or since?
Rapid fluctuations in coolant temp are usually down to air locks - or electrical issues with the gauge.
Since you are noticing coolant level changes for me I would be looking at coolant system bleeding/blockages.

Further - I noticed a difference between the two pump numbers. Yours should have the small vent port circled red below.

04E 121 600 CS
With vent port

04E 121 600 CR
without port

 

[SuperV8]

Can you share a photo of your actual coolant pump - found on the left hand side of the engine.

This small port should be visible on the top of the pump.


Volkswagen 1.4L TSI EA211: Coolant Pump Replacement pdf:

 

[Ollie86rn]

I replied to your IM;

Did this issue happen before they fitted the water pump? or since?
Rapid fluctuations in coolant temp are usually down to air locks - or electrical issues with the gauge.
Since you are noticing coolant level changes for me I would be looking at coolant system bleeding/blockages.

Thanks for the IM and reply.

I have only owned the car for a month or so (and been in the garage most that time) and it has showed the fault pretty much ever drive except when I test drove it and on the 2 1/2 hour drive home.

The pump fitted 04E.121.600.CB which I have been told was superseded 01/09/2021 by 04E.121.600.CS which is the same as you stated. The fact it shows Skoda on the part itself is confusing but seems the correct part is fitted all be it a previous version. Seat technical have finally come back stated the below:

'They agreed with us that the holding of pressure overnight, to the extent it is, can put the suspension elsewhere. They also agreed blockages can of course cause cooling system anomalies depending where the blockage is. They aren't ruling out cylinder head issues, still recommending removal for inspection of coolant channels, gasket etc. Other than that there is no real guidance from their end they can offer on where this blockage could possibly be. If not removing the head, it will be a case of things like, attempting radiator flushes. Removing coolant pipes and trying to check the one way valves by flowing water through them. One hypothesis is that a coolant leak sealer could have been used at some point in its life, the first time the coolant pump was replaced was due to overheating and a leak from it. This could possibly cause restrictions in the system and cause misreading's from sensors. But again, this is speculation.'

At this point I think I may get the car back and strip all the coolant system before I even think about taking the head off. What do you think?