Losing Coolant
01-22-2018, 06:40 AM
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Losing Coolant
Hello,
First post after lurking around for a while. I have a 2012 2.0 TDI A6 and have been losing coolant since I bought the car in November. Initially I was getting a fair bit of white smoke, I took this into my local Indy and had the EGR cooler replaced luckily the used car warranty I had paid £650 of the £710 bill. Since this was done (2 weeks ago) I have had no white smoke, but I am still losing coolant at a similar rate. There are no puddles, so this looks like an internal leak. There are no puddles inside the car, so I don't think its the heater core and I am getting some heat in the cabin. I am getting through about a litre of coolant every 500 miles or so, the loss seems greater on long runs when the car gets up to temp. Sometimes in this weather the car doesn't get up to temp and I don't seem to lose as much. A long motorway drive and it seems to drop quicker. I initially took the car to Audi for a health check and the guy there did a pressure test and that was fine, he asked if some work had been done on the engine as it looked like it might have been out at some point
but never took it back as they wanted £130 an hour for investigation!!
Any ideas what this could be. Car seems to drive nicely and the oil looks fine. I was concerned about head gasket/ cracked head but this seems rare on these cars. The mechanic at the Indy dismissed this as highly unlikely but I'm running out of alternatives. Any advice be welcomed.
Cheers.
First post after lurking around for a while. I have a 2012 2.0 TDI A6 and have been losing coolant since I bought the car in November. Initially I was getting a fair bit of white smoke, I took this into my local Indy and had the EGR cooler replaced luckily the used car warranty I had paid £650 of the £710 bill. Since this was done (2 weeks ago) I have had no white smoke, but I am still losing coolant at a similar rate. There are no puddles, so this looks like an internal leak. There are no puddles inside the car, so I don't think its the heater core and I am getting some heat in the cabin. I am getting through about a litre of coolant every 500 miles or so, the loss seems greater on long runs when the car gets up to temp. Sometimes in this weather the car doesn't get up to temp and I don't seem to lose as much. A long motorway drive and it seems to drop quicker. I initially took the car to Audi for a health check and the guy there did a pressure test and that was fine, he asked if some work had been done on the engine as it looked like it might have been out at some point
but never took it back as they wanted £130 an hour for investigation!!Any ideas what this could be. Car seems to drive nicely and the oil looks fine. I was concerned about head gasket/ cracked head but this seems rare on these cars. The mechanic at the Indy dismissed this as highly unlikely but I'm running out of alternatives. Any advice be welcomed.
Cheers.
01-26-2018, 01:43 AM
#2
AudiWorld Member
It may be the coolant overflow tank in the engine bay. With age and the changes in temperature it develops micro cracks and/or the rubber gasket on the cap shrinks and does not form good seal anymore.
In both cases the coolant only leaks when you shut off the engine because when the water pump stop circulate the hot engine block heats the coolant in the block to highest temperature. That increases the pressure in the cooling system and in the overflow tank and the coolant leaks through the cracks or through the cap seal.
It's not enough to leak and make it's way to the floor so you won't see any liquid under the car. Look under the overflow tank and you should see some coolant residue. Pinkish white if that's your problem.
In both cases the coolant only leaks when you shut off the engine because when the water pump stop circulate the hot engine block heats the coolant in the block to highest temperature. That increases the pressure in the cooling system and in the overflow tank and the coolant leaks through the cracks or through the cap seal.
It's not enough to leak and make it's way to the floor so you won't see any liquid under the car. Look under the overflow tank and you should see some coolant residue. Pinkish white if that's your problem.
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