R&R of the Viscous Fan Clutch on the 1999 E300D


Removal and re-installation of Viscous Coupled Fan, Serpentine Belt Replacement

There is very limited access to the bolt holding the viscous fan to the water pump pulley. In some models removal of the radiator will be required to access the bolt - - clearance is very limited and large hands are a hindrance. The job is straightforward and requires some patience as the bolt holding the visco fan to the water pump pulley is tough to remove due to poor access.

Condition: Over-heating (lack of coupling) or excessive fan noise (too much coupling) due to failure of viscous coupling mechanism and/or loss of viscous oil. My car was doing the later and I had tremendous fan noise once car had been running for just a few minutes.

Tightening values (Anziehdrehmomente):

  • Visco fan/clutch bolt to water pump pulley: 45N*m
  • 3 small bolts holding clutch to plastic fan assy: 10N*m

While the photos of this job show my 1999 E300D, I believe this procedure is nearly identical across the product line where the visco-fan is used. Here is photo from shop manual covering 107/124/126 cars, my W210 utilizes essentially the same procedure:

There are the two tools I had to obtain:
8mm shortie socket

Locking level (holds water pump pulley via hole in rear)

You may be able to fabricate an alternate locking lever. Some say it’s possible to have a helper hold the water pump pulley by hand. Instead of the short 8mm socket, you might be able to use a standard hex key which most would already own, but you would not be able to re-torque the bolt to the required value during re-assembly.

Part numbers are:

  • 103 589 00 40 00 (locking arm)
  • 103 589 01 09 00 (shortie 8mm hex socket)

I purchased both tools from Samstag, I think it was about $40 total.

First step is to free the plastic fan shroud. There are two clips retaining the top edge that slip straight up and the bottom edge is held in place by simple tabs at the base of the radiator (picture below):


There is very limited access on my car making the removal of the bolt holding the fan to the water pump pulley quite a challenge even with the proper tools:

I could tell my car had already been apart (a bit of damage to radiator fins) to have the serpentine belt replaced (based on date code), visco fan was original part installed at factory.

My 3/8” ratchet has a fairly low profile and I barely had adequate room to get the shortie socket in place and attach the ratchet so I could loosen the bolt. I could not get enough leverage on the ratchet and ended up doing this:


I got a spark plug wrench attached to my breaker and slipped it over the end of the ratchet handle and then was able to break the bolt loose. I figured I was home free at this time. However, as the bolt starts to back out of the water pump pulley, the ratchet is moving closer to the radiator making it impossible to remove. I had to back the bolt out most of the way with two fingers and that took quite a while as the head of the bolt was dirty and very tough to turn with fingertips. Prior to re-installation, I sanded the bolt to roughen the surface making re-installation a little easier. Hiring a young child with small hands to do this part of the job would be a huge benefit and time saver!

Here is the locking hole on the rear of the water pump pulley. There are several holes, only 1 is large enough to accommodate the locking tool:

Tool in hole:

Pictures of fan/clutch:


These three screws are removed with a 5mm hex driver:

New vs. Old:

It’s obvious the design of the new unit is heftier.


Fan blade and shroud are now out of the way and access to the serpentine belt and pulleys is excellent. Grab the lever tool from car’s tool kit as it is used to pull back the plastic block so you can remove the bolt holding the heavy spring and release tension on the pulley. Since you’re this far into the job, I’d assess the age and condition of the small damper as this is another routine replacement part.


Once the heavy spring and bolt are removed, force the tensioner pulley downwards to release tension on belt and make removal/re-installation far easier:

Install fresh serpentine belt, check Owner’s Manual for pattern used on your car:

You are ready to re-assemble the visco clutch/fan assembly to the front of the water pump pulley. Just reverse your steps, no tricks required. You may have to wiggle the fan around a bit to get the long bolt back in place. I used my fingers to turn the bolt virtually all the way back in. Once the bolt was seated, I just barely had adequate clearance to use my 3/8” torque wrench and set the final torque.

My little helper holding torque wrench:


Spinning true and quiet :

Fan clutch was approximately $90. Serpentine belt was approximately $35. I selected the Gates belt as they are OES to MBz.

Don’t let the many pictures intimidate, there’s nothing complex about these two tasks - - I just like taking loads of photos when I have time. Again, the only challenging aspect of this job is removing the fan-to-water pump bolt due to minimal access.

LightMan's Step by Step Glowplug change for 1998-99 E300

Ok guys, here it is. The mystery is no more. I will outline the glowplug replacement process, including intake manifold removal.

Tools required

  • Ratchet and socket set with extensions
  • torx bits/sockets
  • allen bits/sockets
  • torque wrench
  • Glowplug reamer (optional)
  • degreaser/carb cleaner
  • rolls of paper towels for black goo
  • Needlenose pliers
  • Flat band clamp pliers

Parts required

  • 6 glowplugs
  • 1 intake manifold gasket

Reasonably competent shade tree mechanics should be able to change their own glowplugs and fuel hoses without paying hefty dealer charges. I changed my glowplugs today with $130 in parts. Most pay $600 at the dealer.

1. The first step is safety. Make sure your car is safely on ramps, a lift or jackstands before you get under your car. Apply the parking brake, and wheel chocks if you have them. Work on a cool engine and use proper hand and eye protection. Don't take chances with your safety. Ok disclaimer over

2. The first step is to remove the valve cover cover. It takes basic allen sockets/bits to remove and comes off easily. If you have trouble with this step, I highly suggest you take your car to the dealer to have the glowplugs changed. While this cover may not be 100% necessary to remove, its good to inspect the integrity of the CCV puck and it's connections, and clean that area. The main reason for removing this cover is so that when you reinstall the manifold you have more room to work with, and have less of a chance of breaking off those flimsy plastic clips that hold the fuel lines in place. Be very careful not to break those and have plastic pieces fall down into the head.

Here is what the valve cover looks like with the cover off:

3. Remove the windshield washer bottle. There is just one nut holding it down, remove the nut, and unplug the sensor from the top. Then using band clamp pliers or needlenose if you're skilled, loosen the clamps on the washer fluid hoses, and remove the hoses. Be careful as fluid will come out of one of them. No problem, just open the reservoir and let it drain back in. Once you've done this, the reservoir is free to pull up and move up near the fuse area and out of the way.

4. Removing the intake manifold. There are several TORX nuts holding the manifold to the head. Remove all of them from the top side of the manifold. look to the right side of the throttlebody/egr valve, and you will see a clamp holding the EGR assembly to the corrugated pipe that comes around from the exhaust manifold to the back of the egr. (Evil, evil pipe). Loosen this clamp with a 10mm socket and extension. Remove the bolt, and clamp. Now get underneath the car, and you'll see another 10mm bolt, I believe of a golden color, which holds the intercooler pipe to the egr. Unscrew this screw. Now remove the 2 vacuum hoses from the EGR. Here is a pic of the one on the EGR valve. Pull it off.
and the other vacuum hose nipple you can see on the lower right with the hose already removed...
here's a pic of the corrugated pipe that meets the back side of the egr, where the clamp is...
Here's the clamp:

Once you've removed the clamp, lower bolt, EGR vac hoses, and intake bolts, the manifold is now free. Pull UP. The EGR assembly remains attached to the manifold and comes up together. Heres what the intercooler pipe and corrugated pipe look like after the manifold is pulled off. You can also see the hole to the right of the intercooler pipe where the bolt must come out from the bottom. It comes up thru this hole and threads into the egr/throttle body when the manifold is reinstalled.

STUFF rags in the holes in the head, so nothing falls in there. As you can see I used the luxurious Brawny rags :-) Also stuff a rag in the intercooler pipe. Here's a pic:

Here's the intake manifold removed...

here's a closer shot of the EGR mounted on the manifold. No, it's not that clean when it comes off

5. Clean your intake manifold. You can use various acids, degreasers, brushes or carb cleaner. The black goop on there is thicker than it looks and hard to get out. I found that biodiesel dissolved the goo quite easily, 10 times easier than carb cleaner or grease lightning etc. If you have bio, or maybe even diesel fuel, set your intake on the grass, and fill it up to the brim and let it soak. It will look sparkly clean and silver after, like this...This will really restore lost performance and cut down on smoke due to more airflow.

6. With the manifold rinsed and drying, it's time to get at the glowplugs. Use needle nose pliers to remove the glowplug caps. Squeeze them gently on each side and pull out toward you. They wont give you any trouble. Easier than spark plug caps.

7. Using a deep socket and extensions, CAREFULLY unthread your glowplugs. DO NOT MUSCLE THEM OUT. THE BIGGEST AND MOST EXPENSIVE MISTAKE YOU CAN MAKE IS BREAKING THEM OFF IN THE HEAD. You'll find they are torqued in there reasonably tightly, but they will give with a little effort. I was hesitant at first to apply any pressure for fear of breaking one. This was good. I tried a different one and it came out more easily. I then sprayed penetrating oil on the stiffer one, and worked on the rest. They all came out easily except for one. I gently attempted to tighten/loosen the plug back and forth a bit, and it came loose easily. Sorry I dont have a pic of the plugs but they are a no brainer, like spark plugs. Look at the new ones you have if you really dont know what you're looking for. Once they are unthreaded, pull them straight out. If they are stuck due to carbon deposits etc, DO NOT try to force them out. Spray penetrating lube down the holes and wait a few mins. THen gently twist and pull them and they should come loose. Again, do not force it and break them off in the head!

Here are my old (52k on them) glowplugs:

8. Optional step - necessary if plugs were very carboned or stuck. I would recommend this step every time, but I wasn't able to due to not having the tool. I have it on order. - Get the appropriate glow plug REAMER tool from mb. RUn the reamer into the glowplug holes to break up carbon and make room for the glowplug. Doing this regularly in my view should help prevent the stuck glowplug/breaking off in the head problem.

9. Install the new glowplugs.You may also want to dab a little anti-seize on the threads. Thread them in and torque to 27NM. Install the glowplug caps, they will push on with an audible CLICK.

10. Remove old intake manifold gasket and clean head's surface. Remove all rags from the head.

11. Align and lay out new intake manifold gasket. Don't worry about it staying totally in place at this point.

12. Reinstall intake manifold onto intercooler tube, and be sure the egr assembly is 'plugged in' to the corrugated pipe. Install the clamp to hold them together, however just tighten enough to get the bolt threaded at this point. Be sure the egr is firmly seated on the intercooler pipe, and the manifold is seated flat on the head. Might take a little push to get it down flat.

13. Using a flashlight, look down the holes on the top of the intake manifold. If the gasket is lined up, install the bolts. If not, lift up very slightly on the manifold, and using a thin/long screwdriver, scoot the gasket until the holes line up. I suggest doing this at one and and then the other. Once you've done that, it's pretty well lined up. Be sure it's totally lined up with one more center bolt, and then reinstall all the manifold bolts. Thread them until they are all snug, not too tight. Then working from the center out, in a top bottom top bottom order, torque these bolts to 20NM, or 14 ft lbs.

14. Tighten the clamp on the corrugated pipe/EGR. Re-attach the two vacuum hoses.

15. Go underneath and reinstall the bolt thru the intercooler pipe to the egr assembly. This will require probably 2-3 extensions.

16. Double check your torque on all bolts.

17. Reinstall washer reservoir, hoses, plug, and nut. Double check everything to make sure you've got everything right, and cleaned up all tools from the engine compartment etc.

18. Reinstall valve cover cover. Tighten bolts to snug.

19. Close hood, start the car up. It should glow and start perfectly, possibly a slight stumble on the very first start. Your glowplug light should have gone out but check engine light will stay on. Look under the hood for any leaks, although there shouldn't be any if you installed the gasket correctly on the manifold. It's also probably a good idea to retorque or check the torque on the manifold bolts after coming back from your first drive.

20. Go to Autozone or equivalent and they will clear the code for free. The OBD port is covered by a little plastic door, down near your shin area, by the parking brake. Standard area and standard OBD plug, will work with all scanners, don't let them tell you any differently

Ok guys, I'm done. I hope this has been a help and has demystified the E300 manifold removal and glowplug change!! No more expensive dealer glowplug visits every 40k!! I've saved a lot of money due to help from internet auto forums and members so here's my turn to give something back. Enjoy!


Additional comments and pics from uberwgn

Yes, I'd like to say thanks to Lightman as I needed this procedure today to remove the IM to access two troublesome bolts on my leaking fuel shutoff valve.

I'll add a couple of photos a minor contribution to this work. A total of 16 bolts are removed to enable removal of the IM. 14 are the bolts holding the IM, the other two are referenced in the photo below:

14 bolts removed here:

10mm bolt on right is accessed from above. 10mm bolt on left is accessed from below. Manifold is ready to be removed, it's that simple:

I'm going to refresh this o-ring. This is at connection between the pressurized air from the I/C to the EGR valve.
There's a lot of "spatter" from exhaust or oily vapors and one of these connections is leaking. It could be the EGR clamp that's leaking.

Block Heater Wiring on the 1995 E300D (W124/OM606)

Let's Wire Up the Block Heater!

It’s getting cold. If you have a diesel, that means that you might want to fire up the block heater. My ’95 E300D is new to me. I did not know if it even had a block heater. A bit of research determined that it does, and I believe that all diesels from at least 1995 onward have block heaters. BUT…they are not wired, unless you or the previous owner took the car back to the dealer for the free heater cord install. (Canadians and the rest of the world – it may be different in colder climates.) Look behind the small removable rectangular section of your plastic front grill on the passenger side to see if the cord is there.

So, I looked, and my cord was not present. So I ordered one – it’s cheap, as it should be. Here’s how to install it. An easy one-beer job.

First jack up the front of the car, place your jack stands, and remove the plastic belly pan, if you still have one. This photo shows what you see when looking down from the top side. The heater is located on the passenger side of the engine block, below the exhaust manifold. It has a black plastic cap on it, assuming it is still there.

Because you are working next to the exhaust manifold, wait until your car is cold to do this job.

The cap was tight on my car so I used some slip joint pliers to grab it and loosen it enough to remove it by hand. It’s a tight fit, but you can reach it from above without much difficulty.

This close-up photo was taken from below and shows the heater with the cap. Nice to have the close-up feature on the digital cam – and long arms to hold the camera where my eyes couldn’t see!

This photo shows the view from the top with the black plastic cap removed – you can see the brass threads on the heater itself.

This photo is a close-up of the heater with the cap removed.

This photo shows the heater cord. 3 prong plug on one end, and two holes on the other to fit the prongs on the heater.

Now you have to get under the car, and plug the heater cord into the heater itself. A bit of feeling and dexterity required, but it is not too difficult. You have to do it pretty much by feel, because you can’t see too well up there. Actually if you are adventurous, you could probably remove the second plastic belly pan and gain more access and visibility under the car, but I did not feel like doing that, and the job is not too hard with it still in place.

So now you have plugged in the heater, you have to route the cord out the front of the car. I have not seen how the dealer techs do it, but I chose to run mine along the transmission oil cooler line. I just zip tied it along that tranny cooler line about every 6 inches or so, no big deal. Then you snake it out of the front of the car, out the trap door in the front fascia.

Here is the last photo with the cord hanging out the front of my bug splattered fascia. Don’t make the same mistake I did at this point. You have to secure the cord firmly in place so it can not drop down and drag on the pavement. Another zip tie or two should do it. I did not do that and managed to drive about 80 miles with the cord dragging! Chewed up the plug quite nicely, but it still works. Now go have another beer and change the oil while your car is nicely up on the jack stands!

Injection Pump Fuel Leak Fix on the 1991 W124 300D Turbo 2.5 (OM602.962)

My car sprung a fuel leak at the injector pump.

The worst part of this job was looking at it, trying to figure it out, getting ready to fix it, then finding out you need a special tool that takes 4 days to get, in order to do the job.

Here are the steps, as I REMEMBER them, and this was on my 1991 300d 2.5 engine, the leak started with 90k on the engine. Note other model years might be different.

You’ll need:
1) A T30 torx socket. A T30 screwdriver will not work, you won’t have the room.
2) A splined socket for your ½ inch (not 3/8”) socket drive. The socket cost $45 or so, then you can resell when done. I think it’s a 32 tooth socket, part M604-0109 at Technitools, or Hazet H4556. Mine is made by Hazet, but others are out there. Check ebay or your local MB dealer.
3) To do it right, you should have a small torque wrench.
4) You need 5 rubber washers. The copper washers, as someone else said and so far I agree, you probably don’t need to replace. Cost of the rubber washers, maybe $3 for all 5.
5) A 14mm short handled open box wrench to fit over the 1/2" tall copper nuts at both ends of the injector lines.
6) A small pick for helping to lift the flat collars.
7) If you want your life easier, take photos left, right, and top of the area reference for reassembly. At a minimum, draw how the Torx wrenched flat collars overlap one another, and note how high or low the STOP button is.
8) Clean the area well. You don't want debris of any kind going into the injector area. This includes any debris as you hang over the engine.

I did mine in a series of wrong steps, so I'm not sure which area to “start with” first, and maybe there is no right area to start in, but basically, what you need to do, is to remove the copper fuel lines, so you can get to the splined valve at the injector pump.

If I had this to do over again, I think I would start with the brackets. You'll see the bracket holding the first set of 3 lines easily. It's on the manifold, you need a 10mm wrench to get those 2 bolts off. The bracket holding the other 2 lines, is hidden and caused me a lot of problems. On my model, looking from the top of the engine down, it's view is sort of occluded by a small dark plastic coated cable of some type, that runs from the mess of wires in front of it, and back to the engine compartment. You have to get rid of that line in order to get the bracket off.


To get that line out of the way, you have to loosen (but not take off) sort of square thing, looking down at it, it’s maybe 3" x 3", and held on by 4 bolts. The upper right bolt of that module will have to be removed, the other 3 loosened pretty well, but not all the way. Once the upper right bolt of that cruise control module is out and the unit is loosened up real well, you can lift that black plastic coated line out a bit, enough to get a 10mm socket onto the bolt under it, and unscrew the injector bracket holding the 2 injector lines together. (Putting that injector bracket back is a real hassle, so look at the bracket once loose, and see how the clip inside the bracket slides back and forth. It is this clip that the bolt must go through when reassembling).

Once the brackets are loose, now loosen both ends of all 5 injector lines with the short 14mm box wrench. Once loose, work the first set of 3 lines so they go back and are out of the way, then do the same with the remaining set of 2 lines.

Once the lines are out of the way, draw a picture of how the flat collars are, which overlaps which, then remove. Again, be careful of getting any debris in the injector! If by chance you strip one, you'll have to carefully use a small vice grip wrench on them, preferably in the upright position so as not to torque them sideways. Once loose the screw come up easily. (There's an annoying brown plastic line right in the way of all this, coming from the fuel filter. I don't know if this could be taken out; I left mine so it'd be less potential problems, but it's reeeeeealy annoying.) Use a pick of some type to help walk the collars up and off from the back as you lift from the front.

Take the STOP lever off. It uses maybe a 6mm wrench at bottom, be careful when it comes loose so as not to lose the nut and tiny washer.

Once the collars are out, use the splined socket on the fuel delivery valves. Some on the forums said they loosened the valves a bit just enough to used a pick to get the rubber seals off. I tried that, and it was a waste of time for me. MUCH simpler to just take the valve out. When you do, be prepared, as a spring will come out the bottom. So go slowly, take the valve out at a sharp angle, to prevent losing the spring. Once completely out, take the old O-ring off by hand. Lightly lube the new
O-ring in some fuel, and put it on. The threads of the valve might have some debris on them, use a paper towel to clean that off so it goes back in better.

Once the valve is ready to install, take the spring out of the valve, and place it by hand directly in the center of fuel delivery area on the IP. Place the valve slowly and directly over it, and screw it down. Do that for all 5, then tighten with the splined socket as tight as they were originally.
The latest service document from Mercedes specifies this torque spec for the delivery valves:
  • Torque to 30 Nm and loosen
  • Torque to 30 Nm and loosen
  • Torque to 30 Nm and then an additional 5 Nm.

Reassemble, making sure to replace any injector clips you may have taken off. The clips are to prevent the lines from clacking together and cracking. If yours broke, you can run the car without them for a while, but best to have them. Put the lines at the injector pump on and tighten completely, but leave the ones at the injectors only hand tight for now.

At this point, everything should be back to where it was, with the exception of the lines at the injector pump, which should be on just hand tight. Crank the car, will probably take 45 seconds of cranking, to get fuel to come out of the lines. When fuel comes out, tighten the lines at the injectors completely, and you're done!!

Start the car and look for any leaks, which unless you did something really stupid, there shouldn't be any. If there is a leak, find and fix. If no leaks, you should be good to go. The car might sound a bit funny at first, but after a few miles, any additional clacking should go away, if not, you might have air in the line. To get air out, you can try starting the car, and SLIGHTLY back off one injector line at the injector (not at the pump). The car will buckle a bit like you're pulling a spark plug off a gas car, once it does that, tighten and go onto the next one until the problem is fixed.

Take it out for a test spin

Injection Pump Stop Lever Oil Leak Fix on the 1984 W201 190D 2.2

The injection pump on my 190D-2.2 (OM601) had a minor oil leak from around the stop lever. I hate the idea of having something leak, so I decided to try to fix it after another forum member (sixto) suggested that it could be an o-ring that needs replacement. I documented the process in case anyone else has a similar problem... (this probably applies to the 602/603 as well but I can't be certain). In total it took less than an hour to do.

Step 1: Remove the air filter, then remove the air filter box. It comes off with four 10mm nuts, two on each side. The four rubber couplers between the filter box and the intake tubes are just held in place by friction.

Step 2: The oil leak is easy to see! The blue arrow is pointing to the stop lever.

Step 3: When the engine is completely cold, clean with 'simple green' degreaser and a toothbrush. Gently rinse with clean water sprayed through an old windex spray bottle. The result:

Step 4: The stop lever can be removed by taking off the nut shown in the photo. Unscrew the nut, then pull the bolt out from above, then slide the stop lever off.

Step 5: On the stop lever shaft, you'll find a crescent ring clip, a washer, and then an o-ring. To remove the clip, rotate it so the gap faces up, then press down on each side of the gap. Don't lose it if it pops off suddenly. Slide the washer out, then pry the o-ring out. Clean any excess oil from the shaft.

Step 6: The o-ring is about 12mm across (outside diameter) and about 2mm thick. The inside diameter is 8mm. When I replaced my spin-on fuel filter on the weekend, I was lucky enough to forget to install the new o-rings that came with the new filter. It turned out that one of those O-rings was exactly the one I needed here!

Step 7: Reinstall the stop lever (New o-ring first, washer second, clip third, then the stop lever, then the nut and bolt). Then put the air filter box back in. All done!

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