Coolant Loss

[JamieC]

So twice now my low coolant light has come on. 2016 2.0 Highline.
I had a quick look and couldn’t see anything obvious so today it’s been to a garage. I mentioned that from reading other posts on here and not seeing anything external I suspect the EGR cooler.
They have been very thorough and done pressure tests, dye etc but basically held their hands up and admitted defeat. They have not yet looked inside the EGR cooler with a endoscope though as per another post and thats the next step.

What seems odd however, is I can top it up to max and for a week it wont move at all. Then suddenly, it can drop to min in a single journey.
The only correlation I can possibly think of is journey time and that in a week of short journeys its fine, but a blast up the motorway and its loosing level.

The garage did have it running hot for 45 mins today on the ramp and all OK.

Just curious if anyone else has suffered this issue but found it to be intermittent or if anyone has any better ideas than it being the EGR cooler?

 

[DXX]

The garage did have it running hot for 45 mins today on the ramp and all OK.

The engine coolant maybe up to temperature (90) but without engine load the exhaust temperature will be low.
Hence the loss of coolant on a motorway run.
You could spend a significant amount £ on garage diagnostics or just replace the EGR.
Not sure what engine model you have but if it doesn’t have a liquid cooled charge air cooler and / or DSG oil cooler it’s fairly safe to say it’s the EGR that’s leaking.
The design is flawed, any metallic heat exchanger will have significant thermal expansion, the reason why they either have internal flexible seals or are fixed one end and allowed to ‘slide’ at the other.
The T6 EGR has neither, it is fixed both ends and so exposed to thermal stress.

 

[JamieC]

The engine coolant maybe up to temperature (90) but without engine load the exhaust temperature will be low.
Hence the loss of coolant on a motorway run.
You could spend a significant amount £ on garage diagnostics or just replace the EGR.
Not sure what engine model you have but if it doesn’t have a liquid cooled charge air cooler and / or DSG oil cooler it’s fairly safe to say it’s the EGR that’s leaking.
The design is flawed, any metallic heat exchanger will have significant thermal expansion, the reason why they either have internal flexible seals or are fixed one end and allowed to ‘slide’ at the other.
The T6 EGR has neither, it is fixed both ends and so exposed to thermal stress.

Thank you for the comprehensive reply

 

[JamieC]

If I had the EGR mapped out, would this stop the coolant loss.
I would imagine regardless of the EGR being used the coolant is still flowing through the vessels? However as I only loose coolant when exhaust is hot, maybe there are solenoid valves on the coolant circuit or something?

Im aware of the arguments for / against mapping, and also have a quote for just replacing the unit.
Just on the fence at the moment as if to try a map first

 

[DXX]

If I had the EGR mapped out, would this stop the coolant loss.
I would imagine regardless of the EGR being used the coolant is still flowing through the vessels? However as I only loose coolant when exhaust is hot, maybe there are solenoid valves on the coolant circuit or something?

Im aware of the arguments for / against mapping, and also have a quote for just replacing the unit.
Just on the fence at the moment as if to try a map first

Initially no, part of the mapping out process should be to fit blanking plates on the exhaust inlet and discharge from the EGR. This would allow the coolant to continue leaking until it filled the void between the blanking plates or the coolant system pressure matched the pressure in the void.
The danger is that if the coolant in the void boiled and turned to steam in a confined space you have an explosive situation, wet steam has a volume 1671 x the volume of the water that evaporated!
You could;
1. Replace the EGR and no mapping out - UK road legal.
2. Replace the EGR and map out - no coolant leak but not UK road legal.
3. Keep the existing EGR but remove the coolant hoses from the EGR and join together - the EGR would definitely be damaged through overheating but no coolant to leak, not UK road legal.

 

[JamieC]

Option 4,
Map out and plate the EGR and either join together / bung off coolant flow and return lines?
The existing EGR would then just be a lump of redundant metal bolted to the side of the engine? No danger from overheating as plated off and no coolant slowly filling it up either?

 

[Bredenoord]

So twice now my low coolant light has come on. 2016 2.0 Highline.
I had a quick look and couldn’t see anything obvious so today it’s been to a garage. I mentioned that from reading other posts on here and not seeing anything external I suspect the EGR cooler.
They have been very thorough and done pressure tests, dye etc but basically held their hands up and admitted defeat. They have not yet looked inside the EGR cooler with a endoscope though as per another post and thats the next step.

What seems odd however, is I can top it up to max and for a week it wont move at all. Then suddenly, it can drop to min in a single journey.
The only correlation I can possibly think of is journey time and that in a week of short journeys its fine, but a blast up the motorway and its loosing level.

The garage did have it running hot for 45 mins today on the ramp and all OK.

Just curious if anyone else has suffered this issue but found it to be intermittent or if anyone has any better ideas than it being the EGR cooler?

I had a similar problem. Ended up being the pipes carrying the coolant were cracked and only leaked when under pressure. So hard to see when parked.

 

[JamieC]

In the garage today having EGR replaced.
They have broken a bolt in the AC condenser and now saying needs a ned condenser fitted at £140 plus two hours labour.
Not quite sitting right with me that. Guessing they removed the whole front of the van, probably as per the workshop manual, and I guess snapped the bolt holding the pipe into the back of the radiator in doing so. S*** happens and now I have to pay for it I guess.

 

[DXX]

In the garage today having EGR replaced.
They have broken a bolt in the AC condenser and now saying needs a ned condenser fitted at £140 plus two hours labour.
Not quite sitting right with me that. Guessing they removed the whole front of the van, probably as per the workshop manual, and I guess snapped the bolt holding the pipe into the back of the radiator in doing so. S*** happens and now I have to pay for it I guess.

I can’t see why you should pay as they broke it.
It’s also perfectly feasible to remove a broken bolt if they know what they are doing.