E220 1995 Viscous Fan Clutch Removal - PeachParts Mercedes-Benz Forum

#1 02-05-2003, 02:00 AM

I have a Merc E220 - W124 - 1995 Sportline

I have had cooling problems and found the Fan Viscous Clutch is shot (I have repaired a similar animal on my Opel Record), but cannot see how this darned thing on the Merc comes off.

There is a large Hex nut about 30 mm across flats which seems to couple it to the water pump pulley (shaft ?) and 4 x 10 mm round hex socket studs fixing into the same pulley. They sit closely around the large nut.

Does the large nut, screw the VFC onto the pump pulley shaft, or is it fastened by the 4 studs. I am shy of wrenching the large nut in case it is not supposed to turn, and shy of removing the 4 x studs for if the pulley falls off.

If you are interested I can tell how to fix the viscous clutch very simply to make it work same as normal without the bi-metal strip.
(this is a little lengthy for this message)

Regards - John Clarke

engatwork · #2 02-05-2003, 06:19 AM

Look for an allen head fastener directly in the middle of the fan. This is the one that needs to come out to remove it. You will have to make a fan "holding" tool to hold the fan still while you remove the center fastener. You can make the tool out of a piece of welding rod, just bent it at the end to slip down into the area and hole in the back of the fan where it holds it.

JimF · #3 02-05-2003, 02:33 PM

I'm interested! Please tell us how to make it work without the bi-metal strip . . .

#4 02-06-2003, 02:17 AM

Hi Jim......I wish trout would take the fly as quickly !

....Here we go.....Based on too facts....a viscous clutch relies on a liquid or semi (viscous) liquid to obtain a couple between primary and sec. turbines........secondly "bee's wax" changes with temperature, from a low rupture stress semi solid medium , to a viscous semi liquid with no help from a bi-metal strip.
Therefore use the bi-metal strip as a paper weight, seal off the control hole (tap and screw), drill and tap an entry into the main turbine housing (mind the swarf), and inject (with everything very warm) about 3/4 to a cup (depending on size of coupling) of melted liquid natural "bee's wax" and seal with screw.
Do not use paralized purified bees wax, the ruture stress index is too high when set.
Natural wax ruptures quickly during a cold / warm start inhibiting a mechanical couple, and starts a high slip couple at about 40 deg. By 60 deg. we have a good lock.

Dependant on the climate one can mix in a large spoon or two of household natural liquid wax polish (which contains wax solvent) before injection to speed up the turbine "lock" if so desired.
My 9 year old Opel Record has been operating (in Africa) for the last three years so modified.

Regards - John

JimF · #5 02-06-2003, 11:27 AM

Have you taken pics of this process??? If so or if you do another one, please take some and send them to me. I will post them on my web page.

If you look at my menu #19, you will see a 'mechanical' mod that works guite well.

#6 02-07-2003, 01:45 AM

Yes thanks Jim, I found your mod. from a search on "viscous fan". earlier in the week.....however ... have to get the durned thing off first Jim.......they do things differantly in Africa it seems.......a recky at sparrow (whilst being watched by a long crested Eagle) revealed no bolt , just the control rod behind the bi-metal slap in the middle.
So it has to be the large nut sitting between the pump boss and the clutch about 25 mm across flats that screws on the pump shaft. No shaft to be seen, just the large nut. Makes life easier as it has the engine to turn against. Will update (with bruised hands) on progress Monday. I suspect this animal maybe a beastie from the succeeding "C" class ????

John

Mick J · #7 02-09-2003, 08:35 AM

Yes, it is the big nut between the fan and the pulley. It has a reverse thread!

#8 02-10-2003, 02:40 AM

Thanks Mick, I chickened out with the large spanner after a couple of sharp hits, not being completely certain it was a left hand thread.
I did dismantle the bi-M strip etc, but could obvously not drain the residue fluid out. I managed to inject about half cup of hot melted wax through the control hole (duly tapped and screwed). The afternoon was hovering on 32 deg C , but much to my joy the coolant temp. now remained steady on 75. Testing with a wooden stick the clutch had now obtained full couple at idle. With engine stopped, can now feel slight resistance to a hand spin. The reason to remove the unit and drain completely is now dependant on a test how completely wax mixes with a small quantity of silicon over the temp. range. The wife has locked up the electric food mixer !!!. At least the unit actually works now, and does not leak.

Thanks for all your help gentlemen, I shall keep you posted.

I have never seen a station wagon version of the E220 over here Mick !

John (the tyke).

Mick J · #9 02-13-2003, 02:07 PM

John,

I bet you've never seen fuel prices like ours over there!

#10 02-17-2003, 10:02 AM

.......From what I hear that is also true Mick.....however the value of the Rand in real terms negates what advantage we may have. Fillet steak has shot up to R100 / kg (7.14 pounds sterling). Decent beer is now R 12 and Guiness is R 14. But with the average working man's salary being about R 10,000 / month......

...Well the tests show that the residue fluid in the turbine chamber does not mix at all well with Bee's wax, so to get optimum performance at the high end I shall have to get the durned thing off and drain it completely before injecting more wax.

It was a good test this weekend which was hovering on 36 deg C (in the shade) on Sunday. During a simulated crawl (locked in 2nd gear) through a game reserve which is about the worst over-heating test one can endure, it never exceeded 100 Deg with the AC on. If I can better this by draining all the fluid out, it will be worth-while ..be in touch.

I am looking at fitting a manual switch for the aux fan in front of the radiator for emergencies. Would you know which of the temperature switches on the front of block puts this on ?????
It does not appear to be the single one, (I bypassed this...nothing happened) but the connections on the double operating switch are not very obvious, and I am too much a born again coward to play Russian roulette.

John