300SDL revitalized clutch fan - PeachParts Mercedes-Benz Forum

sixto · #1 07-22-2003, 12:23 PM

As summer came on, I noticed that the SDL temp gauge would venture to 100C and a little beyond in traffic with the AC on... and it's always on these days. I checked the archives and found instructions on refilling the clutch fan.

http://www.peachparts.com/shopforum/showthread.php?threadid=67800

There was all sorts of grime on the front face of the clutch when I pulled it off the engine so I figure fluid must have leaked out over 16 years. I used the 6000 centistoke stuff from Toyota crammed into the clutch with a medicine dose syringe. I've heard of clutches taking almost 2 bottles (~36ml) but satisfied myself with one bottle for now. There has to be some air for the clutch to disengage. Several methods are outlined. What worked for me is pushing on the syringe plunger until I feel the slightest resistance. Then pulling up on the plunger until I start to extract air. Bleed the syringe, rinse, repeat. It easily swallowed the contents of the Toyota 18ml bottle. I did this with the fan cold and static. I'd have to build a jig to be able to heat and spin the fan between squirts. Maybe a 928 fan comes off like a 617 fan.

Placebo or not, the temp gauge didn't go past 90C yesterday. I even punched it on the exit lane to get it nice and hot at the light at the bottom of the ramp. 90C.

I don't hear the fan kick in for a short while when I start the engine cold. My 450SEL used to do that. Maybe the 300SE did at some point.

The thread suggests that you can use STP oil treatment but from what I remember of my engine building days, that stuff won't come off whatever it touches.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD

fredjj · #2 07-23-2003, 10:14 AM

Sixto thanks for the post and link. Don't know how I missed the earlier posts. Looks like I've got some work ahead of me this weekend.

CSchmidt · #3 07-23-2003, 10:44 AM

Sixto,

I'm probably on the list to do this also. Any tricks on getting the fan/clutch off. I've seen a clamping tool to hold the pulley in place - then another tool to unbolt the clutch assembly? I think others have used a c-clamp and wood blocks to hold the pulley. Will a standard wrench get the bolts off? Recommendations?

Thanks,
Chuck

Jassper · #4 07-23-2003, 11:04 AM

"The thread suggests that you can use STP oil treatment but from what I remember of my engine building days, that stuff won't come off whatever it touches."

It was approximately a month ago when I started the thread and used that STP treatment. The temp hasn't risen past 100 degrees in traffic ever since then. All with stop-and-go traffic and AC on. Before it used to happily climb to 120.

The clutch isn't seized either - it rotates relatively freely. Of course the question is what that STP does in a year's time but should it fail somehow I can always inject some new in to the clutch. Also it could be wiped off with a piece of cloth quite easily.

sixto · #5 07-23-2003, 11:41 AM

Chuck,

On a 617, it's easy to wedge a screwdriver against two of the four bolts while loosening one. On a 603, I fit an 8mm hex key into the single 8mm internal hex bolt holding the fan to the water pump then use a 3/8" breaker bar with a deep 10mm socket for leverage on the hex key. There's a special tool to hold the pulley but I'm able to keep it from spinning by hand. If that weren't sufficient, next thing would be to wedge something soft like a small rolled up towel between the belt and the pulley to increase belt tension while loosening the bolt.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD

gsxr · #6 07-23-2003, 05:24 PM

Chuck, these are the "correct" tools. The home-made spinner works GREAT. The stubby socket is worth spending ~$8 for at the dealer. You can get around the pricey holder tool as others described. With the proper tools, the fan & clutch comes out in less than 5 minutes, easily:

HTH,

Ike Isaacson · #7 08-28-2005, 05:28 PM

need some ideas removing my fan clutch. Have 1987 Mercedes SDL--can't remove the fan clutch. Also need to know if the center bolt has right or left hand threads. Thanks, IKE

#8 08-28-2005, 05:39 PM

Quote:

Originally Posted by Ike Isaacson

need some ideas removing my fan clutch. Have 1987 Mercedes SDL--can't remove the fan clutch. Also need to know if the center bolt has right or left hand threads. Thanks, IKE

I just answered your question over in TECH, counter clockwise for removal.

#9 08-29-2005, 03:06 AM

Hm looks like I may be due for this operation as well.

Can you hear your fan kick in when it gets hot? Mine makes physically no more noise when it is cold than it does when it is hot. I know most clutched fans sound like a hovercraft when they engage.

Ideas? This is the 300SD. Trying to get an idea of if you can audiably hear the fan making more noise when the engine is 100+

pawoSD · #10 08-29-2005, 03:16 AM

My fan definatley needs it then, it doesn't move a whole lot of air in comparison to the one on our '83, which never even reaches 83C, mine still goes to around 90C from time to time, new radiator cap helped, but my fan is loose, even with the engine hot it can be easily turned once the engine is off. It also doesn't make the hovercraft sound that I have noticed on our 83, after a little while of driving with that one or running the engine, it revs that fan up like no tomorrow and moves a TON of air.....maybe I will try to add fluid to it. Its not a huge concern right now, as the highest temp my car has ever reached was a hot day all freeway temp of about 105-110C max. never went any higher, only lower. Probably partly due to the aux fan coming on, it still functions properly and comes on around 95C or so....

#11 08-29-2005, 03:18 AM

Quote:

Originally Posted by pawoSD

My fan definatley needs it then, it doesn't move a whole lot of air in comparison to the one on our '83, which never even reaches 83C, mine still goes to around 90C from time to time, new radiator cap helped, but my fan is loose, even with the engine hot it can be easily turned once the engine is off. It also doesn't make the hovercraft sound that I have noticed on our 83, after a little while of driving with that one or running the engine, it revs that fan up like no tomorrow and moves a TON of air.....maybe I will try to add fluid to it. Its not a huge concern right now, as the highest temp my car has ever reached was a hot day all freeway temp of about 105-110C max. never went any higher, only lower. Probably partly due to the aux fan coming on, it still functions properly and comes on around 95C or so....

Can you hear it making noise from inside the car? (The working one that is)

Hit Man X · #12 08-30-2005, 02:51 PM

Sixto -

Any scoop on how the fan clutch is still operating?

sixto · #13 08-30-2005, 03:25 PM

I have the AC on all the time so I never hear the fan. I suspect some fluid has leaked out because the fan used to roar for a while on cold start and it doesn't do it anymore. Giving the fan a hard turn with the engine off (duh) it doesn't go more than a blade. Sitting in traffic in 100*F ambient temp, the gauge stays around 90*C. R134a can't cool the cabin to my expectation but that's another matter. My SDL only gets to 100*C when I'm going faster than I should be going. I think I posted in July how I forced it to go to 115*C

If the clutch fan gives me problems I will replace it with an electric SPAL fan like NeilV/ke6dcj used when he dropped a C36 M104 in his 88 TE. I don't think he did it for clearance.

You should read JimF's write up on adding a resistor to the coolant temp sensor to trick the aux fan into coming on sooner.

Sixto
95 S420
87 300SDL

gsxr · #14 08-30-2005, 03:41 PM

Jim F's trick about the fan resistor is for M119 engines (and probably M104 as well as M120) but I don't believe it will do anything on an OM60x or M103, which use simple on/off switches. You can add a manual switch to turn the fan on when desired but I haven't found a need for this yet.

I've been wanting to research the SPAL fan a little, but in search of power gains on the M119, not for improved cooling. It may provide better cooling at idle, but I'm afraid it will be noisy, and I'm not sure what the CFM rating is. A big alternator is required but we've already proved that's a simple upgrade.

Besides all the usual stuff to check when your engine is running on the wrong side of 100°C, also check the space between the radiator and condenser, in case you have a nice big dust bunny like this one (which was hiding behind my electric fan) :

Hit Man X · #15 08-30-2005, 06:03 PM

Quote:

Originally Posted by sixto

I have the AC on all the time so I never hear the fan. I suspect some fluid has leaked out because the fan used to roar for a while on cold start and it doesn't do it anymore. Giving the fan a hard turn with the engine off (duh) it doesn't go more than a blade. Sitting in traffic in 100*F ambient temp, the gauge stays around 90*C. R134a can't cool the cabin to my expectation but that's another matter. My SDL only gets to 100*C when I'm going faster than I should be going. I think I posted in July how I forced it to go to 115*C

If the clutch fan gives me problems I will replace it with an electric SPAL fan like NeilV/ke6dcj used when he dropped a C36 M104 in his 88 TE. I don't think he did it for clearance.

You should read JimF's write up on adding a resistor to the coolant temp sensor to trick the aux fan into coming on sooner.

Sixto
95 S420
87 300SDL

I'm not wondering if this is a smarter route to go than shelling out several Mr Bens for a new clutch. Mine currently will spin nearly two full turns when cold...

By chance do you have a link to the Aux Fan write up?