GrantS

Hi All I have an Audi A3 TFSI 1.8 petrol At 155,000 kms the "check oil level light came on while travelling. Bought 1l of oil. Next service was at 156,000km. At approx. 165,000 km i checked the oil and had to put in 1 litre. (Note: dipstick low level (oil indicator comes on) to high level is 1 litre) Next service was at 166,000 ie a week ago. The exhaust pipe was a little sooty but not moist so probably not leaking inlet valve stem or inlet side of turbo. There is no exhaust smoke so not exhaust side either There was no oil on the ground. Don't worry, my story is going to raise something the forum has not discussed. Mechanic found the missing oil in the coolant overflow/ expansion bottle (top of driver's side mudguard). The mechanic gave me a name of an "old school" European car mechanic. He said in his experience it was rarely a turbo or a "head/ pistons" issue. He said that this model of Audi has a coolant / oil cooler with the oil circuit operating at 40 psi and the coolant circuit running at 15 psi. Therefore, any pinhole leaks in the oil tube of the tube in tube heat exchanger will leak oil into the coolant circuit. Short term fix: put a handful of laundry detergent into the expansion tank. This breaks down the oil so that it does cause all the rubber fittings to expand and split and plastic housings. It also allows for better flushing of coolant circuit Longer term: Take out oil cooler (I think it's on the drivers front corner of the motor beneath the air-condition compressor / alternator - can some please confirm). If so, then relatively easy to remove. Test for leak with coolant side filled with water (oil coiler with the ports uppermost and charge oil side with compressed air. If there is a leak there will be bubbles coming up through the water. Replace oil cooler. (Does anybody know how much they cost GBPs?) Please feel free to ask me questions if this doesn't make sense. Regards Kiwi Audi A3 (Grant)