E36 323i overheating?

Gents (and ladies),

I've noticed a turbine like sound and have sourced it to my engine fan. The sound gets progressively more turbine/induction like as the revs increase, which makes sense. The problem is that the shock towers, bonnet and fenders get very, very hot. Both the engine fan and aux fan are working. The temperature needle is at 90 degrees and I know it's working because I neglected to fasten my expansion cap a while ago and the needle went to the red :facepalm:. Apart from that it never exceeds 90 degrees.

It does not happen that often (have noticed it on hot days and when towing in town) but I am concerned due to above mentioned body panels getting hot enough to cook an egg.

Seemingly the temperature gauge and fans work. The engine fan has a slight resistance to it as it should be with viscous fans and the electric aux fan spins freely. The water pump was replaced a while ago as a preventative measure. The coolant level is normal.

I don't know if the thermostat is working properly. Would a faulty thermostat cause the gauge to go beyond 90 degrees?

Any other thoughts?

Edit: on our 316i when I compress either radiator hose (when cold) I can hear the thermostat clicking (probably not the thermostat opening or closing but just the "lid" thingy wiggling) and feel it on the other hose. It does not happen on the 323i.

Edit 2: with "90 degrees" I mean the temperature needle is at 12 'o clock, which may actually be 90 degrees Celsius, too

turbine like sound would point to a failed viscous fan clutch? (not 100% sure)

I'll look into that. What troubles me is that the whole engine bay gets very got but the gauge says the temperature is normal. I know the gauge works (at least when loosing coolant) so it adds to the confusion. Could it be a case of the temperature sensor located on the wrong side of the thermostat or something?

Tested the fan after work. Revved the engine at standstill, aux fan came on and I could stop the engine fan with a rolled up newspaper. Temp. gauge was still in the middle.

So it seems that the viscous fan clutch is faulty. Has anyone repaired this? I've read on a Toyota forum about refilling the unit with viscous oil used in RC cars' diffs.

I still feel uneasy about the temperature needle staying at the middle.

You could also do the electric fan mod and eliminate the viscous fan completely. Search for Freeriders DIY thread.

I've read about the fan delete mod, thanks. Before doing anything like that I want to figure out how the temperature reading is obtained.

Update: I refilled the viscous oil (only place I could get some was at Toyota) and the fan is working fine now. Next time I'll consider replacing it with an electric fan.

Loom said:

Update: I refilled the viscous oil (only place I could get some was at Toyota) and the fan is working fine now. Next time I'll consider replacing it with an electric fan.

Click to expand...

Do you mind posting the oil type/brand/part number, for future reference?

I just asked for viscous oil. Will have a look on the bottle and post it here. It's ridiculously expensive at about R130/R140 for 18ml but still a lot cheaper than a new fan. According to the salesman it was about R80 a year ago. Obviously it will cost less if you can buy it anywhere than a dealership.