Engine overheting

[alikom]

Hello All !

May be you can help me? I own a 525 iX touring (e34 with m50b25 engine, I hope) It is european model. Yesterday suddenly it started overheating, the temp needle goes to red area, the temperature warning goes on. To day I did little study. I did run the car for 10 min or so, it warmed up and temp needle was at 1/2, than I got the road and the teh needle went up to red area. I had AC on. Then I switched off the AC and turned on full interiro heating. The temp needle came in between 1/2 and 3/4 marks. As soon as I turned of the heating it went up to the red area back. I stopped the car and on running engine opened the hood. It seems to me that the fan was not running to fast, even the temp needle was at the begining of red area. I COULD STOP THE FAN BY HAND AND EVEN SPIN IT BACKWARDS WHILE ENGINE WAS RUNNING. Also, when first time (after cooling down overnight and before I did all of above) turned on the engine, while idling auxilary fan went couple of time on , but after I never heared the aux fan voice. The big hoses connected upper left and bottom right corner of radiator both are hot.
Upper one got hot quicker that lower one. Is that simptoms the termostat and fan clutch problems or something else? Thank in advance.

[632 Regal]

first thing I would do is replace that fan clutch! overheating is NOT your friend on these engines.

[genphreak]

first thing I would do is replace that fan clutch! overheating is NOT your friend on these engines.

Indeed, one or two overheats can ruin an L6's lifetime... either now or in a bit later on.

Don't let it go above 3/4 at all, or don't drive it. Fix ASAP.

The needle should stay perfectly in the middle when fixed; so once the fan clutch is renewed, check the operation of the thermo fan too, just in case.

One faulty fan can sometimes be managed by the other fan until extreme conditions (ie bad traffic) are encountered, then all hell can break loose- next thing you know the head is cooked and it's only fixed by an expensive repair and about 2 weeks in the shop.

Good luck- a clutch fan is at least a simple and cheap fix (and a wear item). Nick

[Ross]

Refrain from putting your hand into a moving fan blade after replacing the clutch!

[alikom]

Well, in fact I was not doing that by hand but with peece ow wood. Anyvay the result is the same. I can stop the fan and even spin it backward when engine runs.

[Alexlind123]

You need a new fan clutch, its not too hard to figure out.

[alikom]

You need a new fan clutch, its not too hard to figure out.

Is that only? No thermosta exchange? Soembody told me if I got overheat once, thermostat has to be changed. Is that true?

[alikom]

You need a new fan clutch, its not too hard to figure out.

And how difficult is to change that fan clutch?

[632 Regal]

about a 2 on a 1-10 scaqle of difficulty. do a search it has been covered here extensivly.

[Chris'91'525i]

And how difficult is to change that fan clutch?

It can be very difficult if you turn the big 32mm nut that holds the fan on the wrong way.
It has left hand threads.
So turn the big nut the opposite way that most nuts thread off and on.
Other than that, it's pretty straight forward job........