engine overheating

[Robert63]

Hi all many thanks for all the help and suggestions I have now identified a small leak on the coolant expansion tank. This has now been replaced and overheating problems have now gone. Many thanks all.

[bigwinn]

Glad to hear its fixed- most people who have this issue dont notice immediately due to it being a very fine mist leak

Good job!

[enuff_zed]

Excellent and not too expensive.
I guess the initial leak is not so much letting coolant escape, but dissipating the pressure that holds the coolant below boiling point.

[colb]

Minor leaks can be difficult to find, I invested in a Vaccum Coolant Filler as I have a compressor in my garage, system is drained in the usual way via radiator drain tap or taking off the bottom hose, once drained the vaccum filler is connected to the car via the filler and by turning the appropriate valve on the tool the air is sucked out of the system, you will see the hoses collapse as the vaccum increases, once at the max vaccum the valve is turned and the vaccum guage on the tool is monitored to see if the vaccum remains stable over time. If it drops its a sure sign there is a leak somewhere in the system. A good ear may well direct you to the point of the leak so you can fix it. Once happy with a good vaccum the filler part of the system is used to suck your prepared coolant mix into the system. Worked a treat on a 1.9 Z3 I had in from a Forum member, no trapped air problems in the heater matrix that is often the case when manual bleeding. Kit I got was from ebay, just looked at current listings, most from China and prices seem to have gone up since I got mine.
https://www.ebay.co.uk/itm/302080227585 ... %3A2047675