I have had my current 1990 535i Sport for over 4 years. When I first bought
it I had to replace the fan clutch. A couple of months back I had to replace
the expansion tank and one hose. Other than that, no other cooling problems.
The temp guage always sits on middle.
However, over the last couple of days I have noticed it getting hot when in
traffic. Has been going up between the 3/4 mark and the red. When I get to a
clear bit of road and get moving again it will go back down to the half way
mark. If I hit traffic again it will quite quickly start moving up again.
My first thought is that maybe I need a new fan clutch again. However, I
don't really want to go and spend £50 odd on a new clutch only to find out
the problem is else where.
Are there any reliable tests to find out if the fan coupling IS the problem?
What else could it be?
It has come on very quickly, not gradually, and the temparture will change
quite quickly depending on traffic conditions.
Any help would be greatly appreciated.