My sister's bloke has just bought himself a B7 Cab 1.8T. He knows feck all about cars and only picked it up yesterday and I took a look over it today. First thing I noticed was that the coolant reservoir was virtually empty. No smoke from the exhaust and no noticeable leaks from anywhere, a bit of a mystery! Next thing to check was to see if there was any gunk in the oil filler cap. Thankfully it was clear. The thing which concerned me was that there was quite a bit of air being blown from the oil filler when I removed the cap. I got him to rev the engine slightly and the pressure seemed to reduce. Does this indicate a problem such as a knackered one-way valve or is it just something as simple as a secondary air injection system (i've only tried it when the car was turned on from stone cold)? Someone has suggested this may just be crankcase blowby, but to me it seems like too much to be that. Also, are there any common reasons for these cars losing coolant?