[marti5]

Had this happen on mine all sorted now only took 25 minutes, its for models a couple of years newer than yours but you may have a similar set up:

http://www.e38.org/SI.New.Evaporative.(charcoal).Canister.Purge.Line.pdf

 

[marti5]

There must be a vapour escape pipe blocked or some valve that lets the vapour escape so pressure wont build up, some of my friends have drilled a 2mm hole in the cap but Im sure there must be another vent somewhere.

 

[marti5]

You do have a similar set up as I have, as I suspected.....you do have a charcoal caniser and a vent pipe #7 here:

RealOEM.com   BMW E34 525i ACTIVATED CARBON CONTAINER/TUBING

 

[marti5]

Well 100f is only 37c, so I cant really see a problem driving it as for uprated rad and fan, I dont see why this is necessary. Ive just been over to Belgium and it was 34c over there and all was fine, I believe Germany got up to 36c in a couple of places and thats where they are built. Also Im sure Dubai gets a lot hotter than that and they are driving them around all the time over there.

 

[marti5]

A charcoal canister should never go wrong, your problem will be the venting pipe or even a bad lambda probe as its all controlled from the ECU. take a look on RealOEM.com Online BMW Parts Catalog

 

[marti5]

Thats excellent news and I like the way you sorted the problem, I will keep that for future reference.