How bad is my fan clutch?

[hhy2k]

Brand new issue... why am I not surprised? Anyway, the car is mildly overheats (if I drive with those short surges from light to light). Just idling it does not overheat. Aux fan works w/o AC on (both stages). Heat is OK in the car if I turn it on. Water level was fine this morning.

Now what about the fan clutch?

It seems kind of slow to me. I can easily stop it with a newspaper roll, however it spins if I let it loose. If I observe it while the car shuts down, it turns 4,5,6 full turns. Not consistent. If I force the blade into a turn (while the car is off and warm) it turns about 5-6 blade lenghts (half a spin) and stops. It doesn't seem to spin much faster with higher RPMs. it doesn't have a noise (like many describe it should have). It would never snap a tape just by starting, I can hold it back with my finger easily (Yes, I still have all of them and I am careful)

Do I have a bad fan clutch? And how bad is it? Thanks

[TxGR8White]

replace NOW!

[rcrad6653]

+1

[whale]

I had the same symptoms as you described and changed my coupling two weeks ago. Symptoms gone! If you hold a new coupling bolt in one hand and turn the coupling with the other you will notice resistance. A bad coupling will just spin without resistance. Changing your fan viscous coupling, you might refer to this forums threads 1235682 & 1286633 as an aid in purchasing and installation. Gault has a good reputation for pricing and service but shopping around will save you over a hundred on this part. Removal and installation with the proper special tool to stabalize the water pump pulley took me 15 minutes. Before I obtained the tool I wasted 2 hours trying to remove it without success. P.S. The new BEHR part #11-52-7-502-804 will have a different # than the one inscribed on the old one but it is identical.

[Ladislav]

Definitely replace the fan clutch. It's cheap in comparison to a new engine.

While you have it apart, replace the radiator fan with a new one. An exploded fan can really ruin your day.

[hhy2k]

Yepp, I thought so, it is weak. An other DIY... or better said DIM (do it myself). Unfortunately I'm still on this island where they refuse to make you an oil change if you have a BMW. Not that they have oil filters anyway. They are happy to order one for 40 bucks.

So, I have no clue how I will pull this off without the special tools. I found this method on the net where you can loosen the nut with just a 32mm wrench and a sledge hammer (no kidding). It seems it is a legitimate method. It's for an E39 but I figure it is similar, here it is (see pic):

Belt static friction method:
Remove fan / fan clutch from water pump shaft.
Place open wrench on fan clutch nut (32mm combo wrench). Place wrench forward on nut to avoid hitting vanos body and thermostat hose connector. Strongly strike wrench side at top with heavy hammer to break nut seize (sledge hammer); left hand thread.
Note: Nut is left hand thread, thus unscrew by hitting wrench top from left to right (car front orientation). Serpentine belt static friction on water pump pulley facilitates large enough opposing force to break nut seize. It is important to use a heavy hammer to produce a high instantaneous jerk. Several attempts will be needed before nut seize breaks. Rotate open wrench to reposition for better access.

If belt static friction method is not successful, attempt pulley holding tool method.

So, what do you think? Going back to civilization in less than 20 days... I must repair this thing until then.

[rcrad6653]

nooo..... you can make your own thin tool to jam the shaft and use the appropriate wrench. Threads are reverse. Members here have made them, don't recall which.

[thelostmachine]

my peugeot 505 turbo had three 10.mm nuts you could lock the clutch if needed, a novel idea I would say...

[Noggie]

A long wrench an a big hammer will do the job, I have just done it like 3-4 times om my car recently.
JUST REMEMBER THAT THE THREADS ARE LINKS !!!!!!!!!!!!!!

So you need to tighten to open.... and vice versa.

Thats what I did, just put the wrench on and give it a good whack or three.

Same when you put it back on tighten as much as you can and whack it once or twice to make it stick.

[Rolf Karlstad]

I've made a tool. I can try to describe it in light detail, then find and link an old thread.

Buy a steel framing square, approx 1'x2'. Cut off the short leg. Drill two appropriately sized holes in one end, with appropriately shaped notch facing towards the holes, to allow good engagement to the water pump pulley bolt heads with the holes.

Buy a full-size 32mm wrench (this is what worked with my 530 m60 engine) and place it on the fan clutch nut, which will sandwich the modified framing square into place on the water pump bolt heads, and voila, everything comes apart, just bear in mind that the fan clutch is left-hand threaded.

Edit: just read the above post and I need to plead with everyone not to bash on the 32mm wrench. It's just too easy to fab up a tool with a drill and a hacksaw/dremel/etc. And certainly not to tighten.. since these threads are left-handed, it isn't going to loosen... seems to me that minimal torque is required to install these.

Found a pic of a nice looking fan clutch tool.

[hhy2k]

Thank you everybody! I don't have a garage or anything with me here. The 32mm I'll buy I guess, so fabricating tools is not an option. It seems that in Europe guys just whack it with the sledge hammer Should be alright.

On the other hand I am not yet pozitive that the fan clutch is bad. (I spent the entire evening with reading about this and no post convinced me that is the problem). Could anyone describe how a brand new fan clutch works? It should not coupple to the pump fully ever actually. But then it is hard to tell if it is just slow... and if it looses some of the fluid it gets slow first and then seizes up...

...I'm sorry, I always like to think before I do something

[850NOR]

Originally Posted by hhy2k

Thank you everybody! I don't have a garage or anything with me here. The 32mm I'll buy I guess, so fabricating tools is not an option. It seems that in Europe guys just whack it with the sledge hammer Should be alright.

On the other hand I am not yet pozitive that the fan clutch is bad. (I spent the entire evening with reading about this and no post convinced me that is the problem). Could anyone describe how a brand new fan clutch works? It should not coupple to the pump fully ever actually. But then it is hard to tell if it is just slow... and if it looses some of the fluid it gets slow first and then seizes up...

...I'm sorry, I always like to think before I do something

The fan clutch is quite cheap and it's definately the prime suspect. Just had mine changed at well, and it solved all of my heat problems.
I'd start with that...

Cheers, Jarle

[hhy2k]

I took her out for a drive. 30 minutes. It was almoast impossible to upset that needle. It is cooler outside than during the day though, around 70 opposed to 80ish. The needle doesn't move while standing, I can rev it as much as I want to. I made a few runs uphill (great hills, really steep). Nothing! Reving again, the needle is in the middle. I made the newspaper test again, but I learned that you shouldn't use the entire paper, just one page. The fan is firm that way, newspaper shreds. The only way I was able to move the needle is to drive in M1 uphill 4000 rpm for 300 meters (yards) AC on. The needle moved one square to the right, and started to cool when I stopped.

I know problems don't solve themselves, but I am thinking she just got driven harder today than normally (indeed, I was upset not being able to get a simple oil change). So my question is:

Is it possible (as the manual actually states) that such temprature rises are part of the deal. I know that grandma (no offence) will never see other tempratures than one needle before noon, but driving it a bit harder should icrease the temprature to a certain degree.

Additionally, this is a BMW tradition (I read) I mean the moving needle. They only changed that because of zillions of customer complaints with similar problems. The only cars are the M cars where needles still move as they should. In the 8 though, the needle in the middle represents a temprature range, not a certain temprature, so one can't see the temp rising. Driving harder than usually makes the needle step out quite suddenly from the well known zone... however, even the drivers manual says that it is normal operating temprature anywhere before the red zone...

So what do you think? Anyone is driving his 8 hard sometimes (stop and go hard low speeds, not fast) and see mild temp hikes?

[Koizumi]

Daily driver in the city. L.A. is hot, got the AC on often. Never does the needle move. The only time I had the needle move was with E32 V12 when the radiator had a breach. Temp shot up in a few seconds. Got lucky and didn't sustain any engine damage. And I really mean lucky as BMWs cannot handle even the slightest overheating.

[wokke]

Originally Posted by Koizumi

....And I really mean lucky as BMWs cannot handle even the slightest overheating.

Strongly disagree. My wife had an E34-520i touring (M50). Temp. gauge was broken and some day the water pump failed entirely (well known problem). She ran the engine hot and called me saying the car hardly moves. She managed to come home and I test drove the car in the evening. Started just fine and after a few miles it lost power dramatically. At the end I was creeping into my driveway. Water pump detected as root cause, replaced it and drove the car for another 50.000km w/o any problems. No shot head gasket, no warped head - NOTHING. I admit I was pretty impressed.
Nevertheless I do not recommend this as a test for the M60 or M70

[Noggie]

I just replaced my fan clutch, and if use my hand and try and spin it, it stops right away, maybe 1/8 of a turn max.
when turning it manually it will be quite heavy to turn.
If your fan clutch is busted it means that the fan is not moving as fast as it should, thus not providing enough cooling.
If your clutch has more than 50.000 miles / 90.000km on it it is busted. No question.

[sparklesmcgraw]

My temp has never moved off of center. Once its warmed up obviously.

If it sways higher than dead center, I would get it checked out.

[Toy72]

Definately change the clutch, dude. Like others, I just replaced this 8 months back, fixed all my problems. And I only used a wrench and hammer, whole process took me 15 mins, including bathroom time.

[850NOR]

Originally Posted by Koizumi

Daily driver in the city. L.A. is hot, got the AC on often. Never does the needle move. The only time I had the needle move was with E32 V12 when the radiator had a breach. Temp shot up in a few seconds. Got lucky and didn't sustain any engine damage. And I really mean lucky as BMWs cannot handle even the slightest overheating.

Actually, this is something I think there should be a debate about. How many have actually managed to warp a BMW V12? When I had some heat problems I was scared sh**less because of what I have read on different forums. When I talked to one of the big dealers with one of Norways best e31 experts, and he said that of all of the e31's in Norway (Around a 100), he had never encountered one with a warped head or anything serious as a result of a short temp raise or even a boil. He said that he was pretty sure I had nothing to worry about, and it seems he was right in my case at least. But he reccomended everyone with temp problems to not drive like that for any length of time.

But to be safe, I think it is wise to follow the general rule. And that is: The temp under hard driving or idling should not pass 12o Clock. At least not an entire tick. Then something is up I think.

Cheers, Jarle

[hhy2k]

Originally Posted by sparklesmcgraw

My temp has never moved off of center. Once its warmed up obviously.

I read you live in Scottland, not exactly a hotspot if you ask me. The same goes for Norway by the way, no coincidence that BMW and other car manufacurers test in Death Valley California

*****

Yes, the car has 90 000 km, the fan clutch might be weak, no question. LA traffic is kind of convincing to me. I will change the clutch.

However, I don't know how can anybody misunderstand this (see pic). It is from the 850i owner's manual. Why would the factory print such a thing if it is just not right? I don't want to abuse anyone's patience (I hear: Dude, just change your clutch... and we already told ya...) but what is wrong with the temprature if BMW itself states: The needle may tend to reach the red zone if ambient tempratures and/or (!) engine loads are very high. I just don't get it! Please somebody explain it to me!

Or may be it is a bad translation from German and it means: If you abuse the car in very hot days, the car can overheat, period (and in that case you'd better stop driving it).

I have seen this needle move before (just move, never overheat) a couple of times:


At Joshua Three National Park, 180 km/h uphill HOT

Hollywood Boulevard HOT

Vancouver downtown construction zone TEMPERED

I-70 Utah desert (when pulled over in a lookout) HOT


Needle never moved in Death Valley, Vegas, AZ (and other hot spots)


You guys all saying it is unacceptable, right?

[TxGR8White]

Originally Posted by hhy2k

On the other hand I am not yet pozitive that the fan clutch is bad. (I spent the entire evening with reading about this and no post convinced me that is the problem). Could anyone describe how a brand new fan clutch works? It should not coupple to the pump fully ever actually. But then it is hard to tell if it is just slow... and if it looses some of the fluid it gets slow first and then seizes up...

well, you can think about this: you have described the classic fan clutch failure (it may not have totally happened yet, but friend, the clock is ticking!
As for the excerpt in the BMW manual - I don't know if that is a translation problem, but directly above that statement it says: "..Engine overheated - pull over to a safe area...allow system to cool down..."
These sound like "cover your ass" statements from BMW.
If you still question whether to get a new fanclutch check out what happens when your clutch fails and "locks up"

[Koizumi]

You guys think it's s joke about warped heads? Take a time machine back 20 something years ago with me and my overheated warped M30 block.

[Ladislav]

This can also happen if the fan is old, brittle and weak and simply disintegrates.

Soooo, replace the fan while you replace the fan clutch unless you know that the fan is quite recent. You have to disassemble the fan/clutch already anyway.

Originally Posted by Koizumi

You guys think it's s joke about warped heads? Take a time machine back 20 something years ago with me and my overheated warped M30 block.

Definitely not.

However I have an interesting anecdote about a Chevy which definitely had no aluminium components.

About four decades ago now my downstairs neighbor had an in-line six '63 or '64 Chevy Nova station wagon. One day he decided to take off the valve covers and replace the seal. He's had the car a short while and was going to change the oil afterwards.

When he took the covers off, it looked like they came off black jello - the entire valve train was encased in some places all the way to the top. He started to try to clean it, but had an idea.

He already pulled the plug on the engine oil and the oil had drained. He decided to take it to the self-service car wash about a half mile away and invited me to come along. We got in and we drove there WITHOUT ANY OIL IN THE CRANKCASE. It drove fine.

When we got there he went to town with the high pressure spray, cleaning out the valvetrain and the engine compartment as a whole and he did not care whether he got water into the crankcase or not. He left the engine IDLING the whole time - at least 20-30 minutes.

We then drove the car back WITHOUT OIL. I have no idea what the temp gauge was at.

He proceeded to put the valve cover back on with a new gasket, filled it with oil and proceeded to drive it for as long as he lived there, which was a number of years, WITHOUT ANY ENGINE PROBLEMS WHATSOEVER.

I would definitely not do that with any BMW.

[850NOR]

Originally Posted by Koizumi

You guys think it's s joke about warped heads? Take a time machine back 20 something years ago with me and my overheated warped M30 block.

I'm not saying that this can happen, all of us know it can. But how common is it really on the V12's? The BMW workshop that had my car had a very knowledgeble e31 mechanic and he said that the V12 where not prone to warping. He has worked on a lot of the 8series cars here, and had never experienced anything like this on the V12. I'm just saying what he said...

Cheers, Jarle

[Koizumi]

You live in an ice box homie!