Started up my 2019 Octavia 2L Tdi estate today after it had been sat at work since Wednesday morning, and a low coolant warning came on. I have never had to top this up in any car before. Had the car since January, it had done 6500 then, and its now just ticked over to 17000. Warning light stayed on all the way home (40+ miles) but I had to call at the supermarket. Upon leaving supermarket, warning did not come on. Drove the few miles home and it was fine. I will check the level tomorrow when it is light, but I would have expected the issue to be there all the time?

What was the coolant level at when you purchased?  Where was the level the last time you checked it.

Where was the level when you checked it when the low level warning came on.

Coolant level expands when hot and contracts when cold, so the cold weather could bring up low level warning if the level is at or below the minimum level.

I'll be honest, I have never checked it (and have never had to before with any car). I assumed it was topped up when I bought it from the Skoda dealer. I have not had chance to check it since the warning light came on, as I know it needs to be done when the engine is cold, so I will be checking it tomorrow morning.

You didn't check it when the light came on?

 

I've only ever had TSI engines with skoda and not had any warnings but seen my coolant drop well below the minimum.

 

In 20 years of driving prior to owning my 2016 VRS I've never seen a car lose coolant or drink its oil between  services. That one did both though.

I didn't check it when the light came on as I was in the car park at work, with the light failing and the weather awful, and, as I have never checked the coolant level before, I decided on my driveway in the light was preferable. I kept an eye on the engine temp on the way home, which rose no higher than normal.

My tsi in summer traffic needs some coolant top up, just don't don't add wrong coolant, for mine is G13 which is not easy to find in normal shops. 

Well, I checked the level this morning and it was pretty much in the middle of the two markers. Started the engine and warning came on again. Decided to phone local Skoda dealership but, as service department don't work weekends, they suggested, as I was covered, phoning roadside assistance. Did so, and within an hour, AA man arrived.

 

Upon unscrewing the cap on the reservoir, the level dropped below the minimum so he topped it up, had a quick check for leaks (none found), and that was that. He did say he had seen similar thing on other VW group cars. Been out a few times today, and no issues. Going to be a cold night, so will see if issue happens again tomorrow but hopefully its sorted. 

It’s a sealed system so if you are loosing coolant it is a leak. The leak may not be visible, just a few drips a day but there will be a leak somewhere. My vRS needed a trip to the dealers earlier this year. They put a pressure test on the engine to find out where the leak was. To my shame, I can’t remember where it was but it needed a new part!

As stupid as it may sound the EA288 diesel engines can take around 15000 miles to fully eradicate air within the cooling system from the original build and run in at the factory. 

 

I've seen this happen since it's introduction and more often than not the system is filled to maximum and there are seldom any more reoccurrences.

Just add coolant and monitor the level, in winter it should not drop, if you get alarm again you have a leak. 

I’ve had this happen a few times. Coolant level is fine, temp gauge is fine, but low level coolant warning light came on.

 

To stop it happening, I unplugged the connector on top of the expansion bottle & cleaned the contact pins on the bottle & connector with a fine paint brush. There was a bit of grit around the contact pins, so removed with the brush.

Warning light has never come on again.

 

One thing that should be mentioned is that the TDI engines all use Coolant as part of the Regen process.  I do mental miles, so generally have to top up the G13 in my coolant header tank either once or twice a month.

Fill it up the the maximum level (when the engine is cold - do not do this when the car is warm).

Only if they have a fault that is exacerbated by the regen temperature, its a sealed system with an expansion tank, there should be no loss.

 

Unless of course you are filling the expansion tank to the brim.

 

You can remove my TDi engine from your collective "all TDi engines" that use coolant during regens and I suspect there will be many others saying the same.

@J.R.@Kenny R Sorry Gents.  I've had 5 VW TDI 2.0 engines - they all loose small amounts of coolant (Euro4, Euro5 and Euro6).

My CR140 never needed topping up with coolant in 150k miles. In that time it had a water pump and thermostat done so it would have been refilled twice by a dealer but never by me.

 

Why do you think use coolant during a regen? Sure, the exhaust gases may cause the EGR cooler to get hotter but that shouldn't cause any coolant use.

I have been driving VAG Tdi's since the beginning of this century, the last time I ever topped up coolant was in the last century!

 

I check the level when hot and would top up when cold if it were needed but taking into consideration the expansion when hot, that is to say if when hot the coolant level was 1cm too low I would add enough coolant to bring the level up 1cm when cold which would be a lower level than desired when hot.

5 hours ago, varaderoguy said:

One thing that should be mentioned is that the TDI engines all use Coolant as part of the Regen process. 

 

Can you explain how?

It is explained in this posting from the forum in 2013. The 'use' of coolant is probably down to over-pressuration of the cooling system during regen. The problem has been reported on the TDIforum, the Seat Forum and Golf forums, so it is a known issue.

 

The cooling system just ejects from over-pressuration valve in the cap. I wasn't advocating that the coolant was being used within the regen process and I can understand how my previous comments might have been construed that way.

 

The problem never totally went away, so we are left having to top-up our coolant tanks every so often.

 

Edited 7 December, 20205 yr by varaderoguy

23 hours ago, Jon TDI said:

I’ve had this happen a few times. Coolant level is fine, temp gauge is fine, but low level coolant warning light came on.

 

To stop it happening, I unplugged the connector on top of the expansion bottle & cleaned the contact pins on the bottle & connector with a fine paint brush. There was a bit of grit around the contact pins, so removed with the brush.

Warning light has never come on again.

 

On the mark 2 expansion bottles this was a common problem from about 4 years on.  The pins in the bottle furr up and do not complete the cct and the light comes on.  Scraping the pins or replacing the bottle with the integrated pins solved the problem. Quite often the light would self extinguish after driving but come back on a subsequent usually, cold start.

 

If the coolant level is below the electrodes, what ever arrangement is in use on the Mk3, then it is back to coolant use....