Flashing Coolant Light

[Yetibeard]

coolant, my coolant light intermittently flashes red. Coolant level looks ok when cold, but low when up to temp. When I leave it to cool and unscrew the cap the level fills back up!
Temp gauge works ok and temp remains stable.

What are the common faults?

I still have VW warranty until January, but if like to go in with ”knowledge” and ammo!

(I searched the forum for flashing coolant and only 1 thread came up with black coolant... My coolant is normal colour!)

TIA

 

[Ads_Essex]

I did find this -

Coolant goes down, triggers alert, but bubbles back up when cap is removed

Maybe the OP @Ondro05 can give us an update.

But other than that I’m at a loss. Maybe plugging a laptop in will tell you what temperature your coolant is reaching so you can ascertain whether it’s at a safe level / within parameters

 

[Loz]

Coolant rising when the cap is removed is quite normal, going down below the sensor when hot is not though and could be air trapped elsewhere in the system.
Is the level correct when cold?

 

[Yetibeard]

Coolant rising when the cap is removed is quite normal, going down below the sensor when hot is not though and could be air trapped elsewhere in the system.
Is the level correct when cold?

It was when I checked about 1 week ago. I'm letting it cool again and ill update.

 

[Yetibeard]

Coolant rising when the cap is removed is quite normal, going down below the sensor when hot is not though and could be air trapped elsewhere in the system.
Is the level correct when cold?

After 2 hours cooling down the level is still below MIN, I haven't opened the cap yet

 

[Loz]

After 2 hours cooling down the level is still below MIN, I haven't opened the cap yet

Leave it till the morning.

 

[Teejay1]

Exactly the same thing is happening to mine. Level is correct when cold, after a warm up and release the cap the level rises to or very slightly above the correct level and warning light goes out. Does not seem to effect performance. Worried its a larger problem as I have a trip to Orkney booked in July.

 

[Yetibeard]

Exactly the same thing is happening to mine. Level is correct when cold, after a warm up and release the cap the level rises to or very slightly above the correct level and warning light goes out. Does not seem to effect performance. Worried its a larger problem as I have a trip to Orkney booked in July.

Are you still under warranty period? Has anyone looked at it yet?

 

[Teejay1]

Yes still under warranty, recently serviced and I mentioned it but clearly it was not checked properly.
Going to try tomorrow and if the light comes on again, calling VW Assist.

 

[Yetibeard]

So this morning the level was still well below the MIN. I started the engine and in about 10-20 seconds the warning came back on. I knocked it off and unscrewed the cap, the pressure released and the level came back up to correct level. Put the cap back on, started engine and all was good.

 

[Loz]

So this morning the level was still well below the MIN. I started the engine and in about 10-20 seconds the warning came back on. I knocked it off and unscrewed the cap, the pressure released and the level came back up to correct level. Put the cap back on, started engine and all was good.

no, no, no, the first thing to do was fill it up above the min mark before starting it up then screw the cap back on and leave it alone. repeat tomorrow!

 

[Teejay1]

Checked the level it was looking ok while cold.


Topped it slightly. Started engine and no warning light. Warmed the engine with expansion tank cap off and heater on full as per other thread.
I didn't go any where over the weekend so going to leave her a few days and see if the warning comes back again. If it was just a level warning light would be amber?

Hoping this is not going to spoil my planned trip.

 

[Loz]

This is my cold fill level.

 

[oldiebut goodie]

Mine cold ( not touched in 6 months from new - I assume that the marked zone is all the minimum and that it should be filled higher than that mark) :

 

[The_Lad]

my coolant seems to sit below the min mark when its been parked up but no coolant warning light so I've ignored it

 

[Yetibeard]

My level when cold was below the min, when I unscrewed the cap it came up to exactly the min. Put the cap on on has been ok for the last 2 days.

 

[oldiebut goodie]

Min is the minimum that it should be! ( No point it being marked thus if it is ignored) My view is that the marked zone is all the minimum range and it should be above that when cold and engine off.

 

[Loz]

Min is the minimum that it should be! ( No point it being marked thus if it is ignored) My view is that the marked zone is all the minimum range and it should be above that when cold and engine off.

That is what I was trying to say but @Yetibeard is having problems following instructions (note the smiley, none intended)

 

[Teejay1]

Min is the minimum that it should be! ( No point it being marked thus if it is ignored) My view is that the marked zone is all the minimum range and it should be above that when cold and engine off.

I've bought some coolant and thanks to the posted pictures I've adjusted mine to look similar to those. When cold mine now sits about 2-3 cm above the "min" line

The manual says not be above the line oddly.

Hoping that was the reason for the light but not entirely confident..

 

[Yetibeard]

So the light came back on yesterday, 1st thing in the morning - cold start. After a 5 mile drive, then 10min stop, restarted and no light came on - obviously everything at temp after 5 miles and short stop.

So, why does the level go down over time, but then is ok once the pressure is released as the cap is removed.

I’ll fill up to the level in the pics above once it’s cold again.

Anymore pictures of cold fill level from others?

Cheers