2015 A6 Quattro Avant - not using oil but coolant leaking?
Discussion
Hiya,
Odd ask but has anyone come across any issue with their A6 Avant (Quattro 3.0 Tdi) not using oil but coolant level slowly dropping?
Whilst it’s not been driven massively due to COVID, it’s always been pretty reliable car in its oil usage (I.e normally needs a oil top up of 1ltr every 4K) but it’s currently about 5k since the last top up and it’s still showing full??? I’ve taken it into audi for them the check it (hate the lack of the dipstick) and they say it’s full. Ok so the gauge isn’t faulty (let’s see).
Oddly the coolant warning came on a few weeks back, I topped it up and kept an eye on it, thought it was dropping so popped it to the garage for them to check it out. It was pressure tested it for 4hrs and all was good. They topped it up again but it’s been slowly dropping ever since.
I thought I’d heard about a possible head gasket issue on these with coolant getting into the engine? Anyone got any info on this / is this possible?
Another thought I had (grasping at straws now) was that the passenger wing panel was taken off for respray recently, is there anything behind that that may have come loose / been sliced during refitting that could cause the coolant leaking?
Anyone got any ideas?
Thanks
Odd ask but has anyone come across any issue with their A6 Avant (Quattro 3.0 Tdi) not using oil but coolant level slowly dropping?
Whilst it’s not been driven massively due to COVID, it’s always been pretty reliable car in its oil usage (I.e normally needs a oil top up of 1ltr every 4K) but it’s currently about 5k since the last top up and it’s still showing full??? I’ve taken it into audi for them the check it (hate the lack of the dipstick) and they say it’s full. Ok so the gauge isn’t faulty (let’s see).
Oddly the coolant warning came on a few weeks back, I topped it up and kept an eye on it, thought it was dropping so popped it to the garage for them to check it out. It was pressure tested it for 4hrs and all was good. They topped it up again but it’s been slowly dropping ever since.
I thought I’d heard about a possible head gasket issue on these with coolant getting into the engine? Anyone got any info on this / is this possible?
Another thought I had (grasping at straws now) was that the passenger wing panel was taken off for respray recently, is there anything behind that that may have come loose / been sliced during refitting that could cause the coolant leaking?
Anyone got any ideas?
Thanks
I have experienced exactly the same issue with my wife's 2016 A6 3.0 TDI (on 102k miles) - no oil loss but gradual coolant loss, ultimately causing the car to go into limp mode with next to no coolant in it (the problem having developed at the same time as an unknown coolant level sensor failure).
Our trusty local specialists who carry out diagnosis by proper spannering and experience rather than simply by laptop found no evidence of any external leak of coolant but after a block test found exhaust gasses present in the cooling system, although not to the extent that it was building up excessive pressure. The problem therefore pointed to an EGR cooler fault... which is a shame, because it's a pain to swap over. We have replaced not only the EGR valve and cooler but also the cooler changeover valve, which is buried in the bottom of the V and is itself a common source of leaks and so it made sense to swap out while the car was in bits, together with the connecting elbow, plus a new coolant tank and the aforementioned level sensor.
A total bill £1,400 (incl 7.5 hours of labour at £60ph). I shudder to think what the bill would have been at Audi.
(Edited to add that this work was completed just yesterday, hence being very fresh in the mind!)
Our trusty local specialists who carry out diagnosis by proper spannering and experience rather than simply by laptop found no evidence of any external leak of coolant but after a block test found exhaust gasses present in the cooling system, although not to the extent that it was building up excessive pressure. The problem therefore pointed to an EGR cooler fault... which is a shame, because it's a pain to swap over. We have replaced not only the EGR valve and cooler but also the cooler changeover valve, which is buried in the bottom of the V and is itself a common source of leaks and so it made sense to swap out while the car was in bits, together with the connecting elbow, plus a new coolant tank and the aforementioned level sensor.
A total bill £1,400 (incl 7.5 hours of labour at £60ph). I shudder to think what the bill would have been at Audi.
(Edited to add that this work was completed just yesterday, hence being very fresh in the mind!)
Edited by LankyMcTally on Friday 30th October 14:38
Well she’s mid fix, egr valve checked (and cleaned whilst off but apparently ok), evidence of coolant mixing with oil and intercooler leak likely to have been an issue for some time.
Just hoping there is no long term damage from coolant mixing with the oil and that they can get all those bits back in
Just hoping there is no long term damage from coolant mixing with the oil and that they can get all those bits back in
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