finding a water leak

[Fimbo]

I've had to top up the coolant by about 1 litre per month for the last couple of months in my E46 - I've checked under the oil filler cap and there's no sign of the dreaded 'mayo' and the dipstick seems clear. Any idea where I might start looking for a leak - had the bonnet open today with engine hot and running but couldn't see any obvious leak. Any easy way of identifying a small leak?

Thanks for any help you can offer.

[Slurms]

Check the passengers footwell see if it's damp or greasy..

Your not getting steam coming out the exhaust are you?

[Fimbo]

I'll check footwells. Does the piping run near these areas? I have not noticed steam in exhaust but will have a look.

Thanks

[jas xjr]

not bmw specific but can you smell the water? having grown up driving bangers and still drive one today i can smell that radiator/cooling system water smell. noticed it on my sisters passat before she realised she was even losing water.turns out her heater is now scrap and replacement is more than the car is worth.good luck

[mr.man]

If the coolant leak is in the engine compartment you should be able to smell it. Distinctive fishy smell, the same as when you take the cap off the expansion tank. I had a tiny leak which I tracked down to a hose which had developed a pin prick leak due to old age. In dim light you may even detect a trace of vapour coming off it.

[buffly]

Its not unusual for the expansion tanks to leak on the E46`s, check around the radiator cap for blue traces...