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1999 E300 (OM606.962) 115A->150A alternator replacement

15K views 23 replies 8 participants last post by  tony1963tony 
#1 ·
I have had significant belt tensioner noise at idle for a couple of months. I got around to replacing the tensioner damper and that quieted about half the noise, but the tensioner was still moving significantly at idle, and idling more than a few minutes led to the damper becoming hot.

I had picked up a made-in-China "DB Electrical ABO0269 Alternator (For Mercedes Benz Cl S Sl Class 4.2L 5.0L 6.0L 150 Amp 1994-2002)" from Amazon last Fall in anticipation of removing the original Bosch 115A unit for potential overhaul, which I know to be original because I have all the receipts on this car from new. With over 160k miles, I normally replace starter/alternator/water pump on my cars; the alternator is top of my list for this one. That alternator application is reputed to be a direct replacement for the original, with higher current capacity.

Because replacing only the tensioner damper did not solve the noise-at-idle problem entirely, I figured that I now have a good reason to swap out the alternator and check the OAP (Overrunning Alternator Pulley), which is designed to prevent just this sort of situation. When removed, I found that my original, OEM OAP was/is locked solid. The alternator I purchased comes with a solid pulley, so I also bought an INA 602-150-00-60 OAP.

And, I needed a pulley tool set, in addition to my regular shop tools.

These proved to be a bolt-in replacement for the 115A Bosch.

DB Electrical ABO0269 Alternator (For Mercedes Benz Cl S Sl Class 4.2L 5.0L 6.0L 150 Amp 1994-2002), $126
INA 602-150-00-60, $57
Lisle 57650 Alternator Decoupler Tool Set, $26

Physical comparison:



I assume an impact wrench is needed to remove the 22mm nut to remove the solid pulley, but other methods have been used. As I'm not re-using the pulley, I could have used a regular ratchet and strap wrench, vise, etc. but because I was not certain that I wouldn't have to return this alternator, it was best if I left no tool marks ;)



Rear view of the INA OAP:



Front view of the INA OAP:



Getting ahead of myself, front view of the old, OEM INA OAP. It is locked up solid, and was the reason for my noise and excessive tensioner movement at idle:


Lisle 57650 Alternator Decoupler Tool Set
Lisle 57650 pulley R&R tool set:



I used the 31T Spline and 10mm triple square tools:



I used a 7/8" wrench for the 31T spline adapter, and a box-end 10mm for the 10mm triple spline, but I definitely needed more leverage for that small wrench. The 18" pipe section was truly necessary:



I was originally going to remove the intercooler pipe section and drop the alternator out the bottom. I used this tool to loosen the alternator's top bolt:



However, after loosening with that perfect tool, the top bolt would not clear the fan.



Therefore, I figured I had to remove the fan to proceed. After fan removal, I then didn't need that GearWrench ratcheting E14 wrench and could have used a std. E14 socket, which is what I used on the alternator's lower bolt (using a 1" 3/8" extension; not everybody has a shorty 1" extension, but I'd run into this kind of problem before).



Kris will be pleased to note that after I removed the fan, I decided to leave the fan & fan clutch off. I've run fanless on other (older) vehicles many times, and Kris' testimony about running his E300 diesel fanless for years gives me confidence.

[Removing the fan is bitchy. There isn't enough room to manipulate tools or the screws that retain the plastic fan to the fan clutch. There are only three socket-head screws, 5mm hex wrench to remove them, but no room for even a 1/4" air ratchet: I removed them all by hand and it was probably twenty minutes' work, with lots of use of my magnet-on-a-stick tool, as I dropped the wrench a half-dozen times at least. I do not want to do that job more than twice. And access to everything up front is so much nicer with the fan & shroud out of the way!]

Fan clutch removed:



Not shown: removing the splash panel and disconnecting the two leads for the rear of the alternator (13mm for the charge lead, 10mm for the D+). One is supposed to disconnect the battery when doing this.

Imagine my surprise when I was able to then remove the alternator out the top! The cardboard is there to protect the radiator fins from damage, and it was needed, but while tight the lower radiator hose did allow enough room to snake the old alternator out and the new one in:



Rear of alternator after installation. The alternate placement ("clocking") of the rear makes the charge lead appear taut, but it's not. I will monitor this to see if a shiny spot develops on the intercooler pipe; if so, I may remove the alternator and attempt to re-clock it (if possible) to provide more slack. Lack of slack may or may not present a future problem.



I started it and it seems to work OK. I have not driven it, but I feel this was a success. There is no more tensioner movement or noise at idle.
 
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#2 ·
I just have a few questions. Why not just buy a new alternator or even the reman alternator since the reman is only about $20 more than what you spent? It would have been quicker and easier. Also why did you remove the fan separate from the clutch while it was still on the car? Why not remove the fan and clutch together as one piece?
 
#3 ·
Also why did you remove the fan separate from the clutch while it was still on the car? Why not remove the fan and clutch together as one piece?
Having done this job multiple times (and Kris would be happy to know that I'm currently running fanless too), I can answer this. The main bolt that holds the clutch to the pulley is extremely tight, and after removing the upper radiator bracket and shoving the radiator backward, you barely have room for a standard tool with a hex bit. Plus there's the fan blades that spin, the radiator fins and your hulk like hands in that space.

Trying to remove that bolt results in the fan rotating, so you need to either have the original fan pulley removal tool, or ghettorig something hideous. Keep in mind all that without breaking the fan blades, damaging the fins or cutting your hands on the unnatural amount of sharp corners this engine seems to hide.

But the 3 bolts holding the fan to the fan clutch? Easy peasy.
 
#5 ·
The tool he bought for this alternator job can be reused for another pulley or reused for a different job....whereas a fan clutch removal tool costs $50 for a one (or two) time use. Then it'll sit on a shelf gathering dust. What's worse is that sometimes it's manufacturer specific. Can't use it on a different car. That's a waste of $50.

Hell, I know mechanics who can't justify buying the tool. They'd rather spend the $50 on a snap on bolt removal drill bits (cuz those break all the damn time) or better yet for beer.

But then again those guys fabricated their own clutch removal tools, so.... idk?

lol
 
#7 ·
The tool he bought for this alternator job can be reused for another pulley or reused for a different job....whereas a fan clutch removal tool costs $50 for a one (or two) time use. Then it'll sit on a shelf gathering dust. What's worse is that sometimes it's manufacturer specific. Can't use it on a different car. That's a waste of $50.
[chuckle]
I actually bought one of the universal fan clutch removal tool sets (OTC? Can't recall) because my Ford's clutch can't be removed without. Of course, it's useless on the MB. Yes, it's sitting on a shelf gathering dust. My heirs will be amused.

I like tools . . . but this problem is easily worked around.

I like electric fans, myself. I had a JC Whitney electric fan kit on like four different cars (moved from one to another as I sold the cars), including the car in my avatar. Old cars didn't use a fan clutch, and the noise at highway speed was tremendous (as the current president says); removing the fan and/or switching to the electric fan made a big difference on a couple of those cars (and one pickup).
 
#9 ·
With those single bolts on fan clutches you never know.
On E300DT the bolt was extremely highly torqued and I was forced to remove pump with clutch on, what made it quite a long job.
Than even I was replacing pump and clutch, just for the sake of it I put the assemble on driveway and with big pipe wrenches was able to break the bolt loose to remove it with fingers later. I estimate it took about 200 ft-lb to move the bolt.
So when lately I had to remove identical clutch on my SL500 I was pretty stressed, but the bolt come pretty easy.
So don't assume anything.
I don't think those cars ever draw 105 amp, so would not worry about wiring.
My new Ford truck coming this months is ordered with 1500W electric heater and I was forced to get dual alternators.
 
#11 ·
With diesel taking 5 miles before you START having cabin heat, I figured out it will be nice option even when I don't plan to stay in areas where mornings get colder than 40F.
Read on the forum that Canadian models of W211 do have electric cabin heater standard with 200 amp alternator.
One of the owners seeking replacement alternator got sticker shock.
 
#12 ·
Funny thing is, when I bought my current E300TD from Kajtek and put the fan and clutch into the car (I bought it fanless), I put about 80lb on the bolt holding it together.

Fast forward couple months later, doing thermostat + bunch other jobs, I tried to remove the fan. Key word being "tried". I eventually had to remove the handle from my floor jack and use it as a cheater bar to even crack it open. The bolt definitely tightened itself during all this, to at least 150lb or more.

For reference, my 3/8 rachet that I used to tighten the bolt was less than 1 feet long, and I verified with a torque wrench.
 
#14 ·
Thanks for the write-up. Just bought these exact parts for my OM606 swap into my Expedition G project.
 
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#15 · (Edited)
A bit off topic but i wanted to share this in case anyone goes through similar experience. Check your Lisle 57650 kit first before considering using force :p

I just received mine via Amazon and there are two issues with it:

1 - The 10mm Hex socket is actually a 11mm Hex (even though stamped as 10mm); [EDIT: Incorrect statement as the hex is actually a 10mm FEMALE hex, which is the correct part. Apologies for the confusion)]
2 - The 33T spline hollow socket, which one would need for the job described above, is actually a 34T spline.

No idea how this happened but this is some poor QC on Lisle's side. I should receive a replacement soon (thanks Jeff). Hopefully with the correct contents.
 
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#16 · (Edited)
I got the replacement Lisle kit in and this time it included the correct parts (although it seemed). Now I was ready to follow OP's procedure to install a new pulley on my new alternator and clock it to the right orientation. Here's my write up for your entertainment. I apologize in advance for high-jacking OP's thread, but i think this may assist some peeps performing the same swap as described by Al_Savage.

Remove shaft nut on new alt with impact:
Machine Gear Engineering Hardware accessory Rotor

Remove nut, pulley and spacer:
Wood Hardwood Metal Wood stain Natural material

My spacer has an upset end on the side facing away from the pulley (towards the alternator)
Wood Hardwood Jewellery Ring Metal

The side facing the pulley is smooth:
Wood Hardwood Jewellery Metal Circle

Remove the (4ea.) 8mm bolts that hold the alt body together:
Blue Technology Aqua Gas Teal

Compare old vs new alt for clocking rotation. Looks like i need 180°:
Gear Machine Engineering Auto part Metal

After clocking the new alt and re-installing the bolts (right side):
Clutch part Machine Auto part Circle Engineering
 
#17 ·
Now for the new pulley install.

New pulley:
2669507

For installation of the new pulley i needed to use the 33T spline hollow nut and 10mm triple square bit from the lisle kit:
2669508

Turns out, even though the 33T spline nut has the correct spline number, the nut hole is too small to allow for sufficient passage of the 10mm bit! This is as far as the bit goes through the nut, which is not enough for the bit to engage the 10mm T square nut in the alternator.
2669510

As the same was true for the included T50 Torx bit that is included in the kit, i considered to drill out the nut hole just a tad. If that wouldn't work i would grind off the edges of the bit to make it more round. Drilling first however. A 12.5mm bit should do the trick, if this worked. The nut looked to be hardened from my point of view (not an materials expert):
2669511

Yeah, that didn't really go anywhere. Even with cutting cutting oil and (very) low speed, the drill bit started to overheat. So i opted to take the grinder to the bit and shave off some material along a length just long enough to allow sufficient passage through the nut:
2669512

This should do it:
2669513

Install the pulley kit and tighten the new pulley to the alternator (22mm box for teh nut, 11mm box for the bit):
2669514
 
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#19 ·
OK, so now for a side comparison old vs new:
2669515

In close up, you can see that the new pulley 'pushes' the new alt up by about a mm or 2:
2669516

This means that when mounted on the engine, the pulley would stick out towards the fan by this offset, which means the pulley would not be aligned perfectly with the belt. Upon closer look, the new pulley is a bit different that the original pulley from the old alt:
2669517

2669518

2669519

The alternators are also slightly different from each other:
2669520

2669521

I found some washers with the exact ID and OD of that new spacer that came with the new alt (the one with the upset end from two post up):
2669522


2669524

The stack of three is just about a hair less in thickness that the spacer.
 
#20 ·
Here's the comparison after re-installing the new pulley:
2669525

Up close:
2669526

Pretty good. With the replacement spacer washers, the pulley is still clearing the alt body:
2669532

Good luck to anyone doing the same swap.
 
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#21 ·
You are doing finer work than I here.

In an ideal world, belts & couplings are aligned near-perfectly. In practice, esp. with multi-vee belts, a misalignment of .040" over around 8" would not be cause for great concern . . . but since you looked for and found this issue early in your project, and it's low-cost to remedy . . . Good Work!
 
#22 ·
You are doing finer work than I here.

In an ideal world, belts & couplings are aligned near-perfectly. In practice, esp. with multi-vee belts, a misalignment of .040" over around 8" would not be cause for great concern . . . but since you looked for and found this issue early in your project, and it's low-cost to remedy . . . Good Work!
Thank you SIr.
I figured that small offset would not be a real issue with all the vibrations going on during operation. But since i had the parts available and working on the bench vs in the car, I opted to remedy it as best i could.
 
#23 ·
Thank you so much for the detailed guide, definitely going to do this fix on my W202
Also, what had you done to have no leaks on the pass side of the block? If you look at mine there's leaks and gunk everywhere
 
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