I was perusing my 110 engine manual today looking for some info on engine mount wear limits for Peter (found nothing) and I stumbled across the best diagnostic procedure I've ever seen or determining the health of a viscous fan clutch so I thought I'd post it here for future reference.
First of all, if you're keeping one of these units (viscous clutch) for a spare, it must always be stored on edge as it mounts in the car. I had heard this before, but the MB manual confirmed it in black and white. IF it's stored flat the fluid will migrate to areas it shouldn't be and the clutch will never work right again.
Proper operation:
Normally the clutch will be engaged for the first 1-3 minutes of cold engine operation as the settled fluid is pushed into the storage cavity. Thereafter the clutch should be disengaged and fan speed should be limited to about 2100 RPM no matter what speed the engine is revved to. When coolant temp goes over 95C a bimetalic coil opens a valve and the fluid migrates to an area where the clutch is engaged and the fan will drive at engine speed up to a max of about 3500 rpm.
Diagnostic procedure:
Operate engine at idle for 3-5 minutes. Increase engine speed to 4200 rpm and use a thermometer to verify when the coolant temperature goes over 95 C. Around the time 95C is reached you should be able to audibly hear the fan speed up by about 1,000 RPM.
a fan speed change can also be spotted visually if you're able to observe the fan with a strobe light.
I have mentioned this before but I have just purchased a Kenlowe kit cost £107 + VAT obviously no good for those who what to keep their G standard but a good alternative to fluid fan as less drag, less noise, recommended 10% fuel saving and engine heats up quicker saving on wear and tear Ill give more details when I have fitted it next weekend I expect
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Nicholas Greene
Criminal Psychologist
Neuvic Entier
FRANCE
I have mentioned this before but I have just purchased a Kenlowe kit cost £107 + VAT obviously no good for those who what to keep their G standard but a good alternative to fluid fan as less drag, less noise, recommended 10% fuel saving and engine heats up quicker saving on wear and tear Ill give more details when I have fitted it next weekend I expect
Hello,
Please send details of the product,where did you buy it from?,How did the instalation work, and finly How does it work.
Thank you very much,
Guy
http://www.kenlowe.co.uk/fans/consumers/fans06.html
is the site. just fill in the deatils on the application page and they will give all details I am fitting it this weekend all being well ill tell you how it goes but I have done one before and they are very easy although when i did one last the rad had to be drilled for the sensor but now the sensor fits in a hose without drilling
http://www.kenlowe.co.uk/fans/consumers/fans06.html
is the site. just fill in the deatils on the application page and they will give all details I am fitting it this weekend all being well ill tell you how it goes but I have done one before and they are very easy although when i did one last the rad had to be drilled for the sensor but now the sensor fits in a hose without drilling
Hello,
Thank you for the web site.
Can you please let me know which model did you buy and how the instalation went?
Thanks,
Guy
Did you notice in the owners manual that there is an emergency mode that allows one to lock the fan to the pulley, should the viscos coupling fail? A neat feature that I did not know about after these many years of driving MB diesels. I suspect this feature is also on the gasoline models.
No Thomas, the operator's manual for my 280GE contains no such reference, as far as I could tell.
Would you mind posting some details or maybe scanning a picture from your manual? It would be a great troubleshooting tool, in addition to a great way to limp home in the event of a fan clutch failure. Very "G-like" I think. :^)
Reference number 6.8 in my manual - (manual number 460 584 1196)
Roly,
The pictures I am sending to Dave via post are a bit more detailed of the little "sheet metal tab", but the mounting looks the same as your photo. It is clearly a different fan-to-pulley set-up than I have on my 1980 300G, since this manual seems to be for a late 1980's G.
This manual has a very helpful trouble shooting section including "preparing the vehicle for storage and service after storage" and "steering" (problems), and details regarding "tow starting" and "towing". The information is a bit more detailed than the German language version that came with my G (460 584 10 96) and is 26 pages longer.
Linear Mode
