1/4 Million Km 2015 E250 Maintenance time!
I am the original owner and I'm trying to do a good job maintaining the car: 28 oil changes, multiple air filters, fuel filters, cabin filters, etc. I changed the transmission fluid at 75K. Getting ready to do that again now.
I just changed the rear differential fluid (first time - oversight). Fluid was very dirty and the plugs were just about rusted out.
I've got the serpentine belt on order. I plan to change it and check the tensioner and pulleys and water pump. Coolant is original. I suspect I should have just bought all of it, but I figured I'd spin 'em first. I inspected this a couple of years ago and it was all running like new then.
New brake calipers, brake pads (Akebonos are awesome!) and fluid. New tires.
I feel the front end wander a little under braking. I replaced the sway bar link (bushings shot). I assume I'll need to replace the front control arms too to get the car driving like new again.
What else do contemplate for pro-active maintenance on a high mileage car? I'd like this car to go another 5 years and ~50K miles. Thoughts???
Thanks,
Mike
Last edited by mfab; May 6, 2025 at 10:56 AM.




I am the original owner and I'm trying to do a good job maintaining the car: 28 oil changes, multiple air filters, fuel filters, cabin filters, etc. I changed the transmission fluid at 75K. Getting ready to do that again now.
I just changed the rear differential fluid (first time - oversight). Fluid was very dirty and the plugs were just about rusted out.
I've got the serpentine belt on order. I plan to change it and check the tensioner and pulleys and water pump. Coolant is original. I suspect I should have just bought all of it, but I figured I'd spin 'em first. I inspected this a couple of years ago and it was all running like new then.
New brake calipers, brake pads (Akebonos are awesome!) and fluid. New tires.
I feel the front end wander a little under braking. I replaced the sway bar link (bushings shot). I assume I'll need to replace the front control arms too to get the car driving like new again.
What else do contemplate for pro-active maintenance on a high mileage car? I'd like this car to go another 5 years and ~50K miles. Thoughts???
Thanks,
Mike
The couple things I would add are
- DENSO radiator
- Tstat
- ALT OE brush Module
- seal electric connectors at front/rear end
- Any camshaft CPS on 300D??
- glow plugs + control module
- rear sway bar links
- adjust wheel bearings free play
- clear roof drains from overflowing
I dunno 4M besides passenger front shaft is coming...
The couple things I would add are
- DENSO radiator
- Tstat
- ALT OE brush Module
- seal electric connectors at front/rear end
- Any camshaft CPS on 300D??
- glow plugs + control module
- rear sway bar links
- adjust wheel bearings free play
- clear roof drains from overflowing
I dunno 4M besides passenger front shaft is coming...
Thanks!
/
The couple things I would add are
- DENSO radiator
- Tstat
- ALT OE brush Module
- seal electric connectors at front/rear end
- Any camshaft CPS on 300D??
- glow plugs + control module
- rear sway bar links
- adjust wheel bearings free play
- clear roof drains from overflowing
I dunno 4M besides passenger front shaft is coming...




This is particularly important for bumper sensors/RADARS
-- Low hanging exposed connectors:
- A/C compressor: clutch + valve
- ISM Module connector.
Last edited by CaliBenzDriver; May 6, 2025 at 04:47 PM.
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For now it sits in my glovebox.
/
Last edited by mfab; May 6, 2025 at 06:32 PM.
https://www.youtube.com/watch?v=L1s5-AMb7A4
/
Here are some stories of it failing because of not changing fluid:
https://mbworld.org/forums/glc-class...placement.html
https://mbworld.org/forums/gls-class...ferential.html




01. All engine mounts
02. Tranny mount
03. All for dampers/shock absorber and the top mount plate/bushings and the bump stop foam/rubber.
04. Front suspension control arms and the L shape ball joint if it does use it.
05. Tie rod end the short one and the long one, this is the steering system.
06. 2 of bushings at the rear wheel carrier / knuckle
07. Rear spring arm bushing at the rear subframe
08. The propeller shaft ( main drive shaft ) middle bearing and boot.
09. 4 of rear subframe mounts , if it already sunk too much and differential bushings at rear (2) while at it and differential mount at front (1).
10. Rear suspension arms, 4 of them ( spring arm no need ), you need to inspect . 4 wheel alignment as in rear camber reading can help to figure it out.
11. Wheel alignment can show the camber and caster value of front 2 suspension arms geometry.
12. The rear tire wear pattern so far ( perhaps 3 - 4 sets of tires consumed already ? ) will be a good database.
13. 4matic shaft out of the rear of the G7 tranny, there is a yoke there which will wear out. Inspect.
14. Inspect rear & front spring condition, if you have reference ride height when new, you can use it as reference for today's condition, how much sagging is occuring.
15. Measure thickness of front and rear rotor. Their useful life is only like 2mm, that is it. Actually brake calipers are serviceable when the repair kit is available, no need new one.
16. All of your cooling and oiling system hoses or plastics/rubber hose or pipe, inspect them well and best to replace them all.
17. Test and calibrate all of your fuel injectors.
18. Inspect vacuum pump, make sure it still can produce negative pressure and how fast it can achieve the maximum negative pressure.
19. All plastic and rubber fuel hoses from tank to engine, replace them all. I wonder if diesel version W212, is the fuel tank output to engine using the blue plastic hose ? Gasoline one uses that blue plastic hose.
Now you wonder, is it worth all above for 50,000 miles and 5 years more of use ?

01. All engine mounts
02. Tranny mount
03. All for dampers/shock absorber and the top mount plate/bushings and the bump stop foam/rubber.
04. Front suspension control arms and the L shape ball joint if it does use it.
05. Tie rod end the short one and the long one, this is the steering system.
06. 2 of bushings at the rear wheel carrier / knuckle
07. Rear spring arm bushing at the rear subframe
08. The propeller shaft ( main drive shaft ) middle bearing and boot.
09. 4 of rear subframe mounts , if it already sunk too much and differential bushings at rear (2) while at it and differential mount at front (1).
10. Rear suspension arms, 4 of them ( spring arm no need ), you need to inspect . 4 wheel alignment as in rear camber reading can help to figure it out.
11. Wheel alignment can show the camber and caster value of front 2 suspension arms geometry.
12. The rear tire wear pattern so far ( perhaps 3 - 4 sets of tires consumed already ? ) will be a good database.
13. 4matic shaft out of the rear of the G7 tranny, there is a yoke there which will wear out. Inspect.
14. Inspect rear & front spring condition, if you have reference ride height when new, you can use it as reference for today's condition, how much sagging is occuring.
15. Measure thickness of front and rear rotor. Their useful life is only like 2mm, that is it. Actually brake calipers are serviceable when the repair kit is available, no need new one.
16. All of your cooling and oiling system hoses or plastics/rubber hose or pipe, inspect them well and best to replace them all.
17. Test and calibrate all of your fuel injectors.
18. Inspect vacuum pump, make sure it still can produce negative pressure and how fast it can achieve the maximum negative pressure.
19. All plastic and rubber fuel hoses from tank to engine, replace them all. I wonder if diesel version W212, is the fuel tank output to engine using the blue plastic hose ? Gasoline one uses that blue plastic hose.
Now you wonder, is it worth all above for 50,000 miles and 5 years more of use ?

Happy Driving
Coolant and water pump (!) are still original to the car. I installed a new serpentine belt last night (took less than 10 minutes) and everything in there is spinning nicely. So for now the water pump and coolant stay.
I need to pick my spots and prioritize. As you can see there's a long list!
The problem with the water pump is a failure leaves you on the side of the road.
/
Last edited by mfab; May 7, 2025 at 08:08 AM.
01. All engine mounts
02. Tranny mount
03. All for dampers/shock absorber and the top mount plate/bushings and the bump stop foam/rubber.
04. Front suspension control arms and the L shape ball joint if it does use it.
05. Tie rod end the short one and the long one, this is the steering system.
06. 2 of bushings at the rear wheel carrier / knuckle
07. Rear spring arm bushing at the rear subframe
08. The propeller shaft ( main drive shaft ) middle bearing and boot.
09. 4 of rear subframe mounts , if it already sunk too much and differential bushings at rear (2) while at it and differential mount at front (1).
10. Rear suspension arms, 4 of them ( spring arm no need ), you need to inspect . 4 wheel alignment as in rear camber reading can help to figure it out.
11. Wheel alignment can show the camber and caster value of front 2 suspension arms geometry.
12. The rear tire wear pattern so far ( perhaps 3 - 4 sets of tires consumed already ? ) will be a good database.
13. 4matic shaft out of the rear of the G7 tranny, there is a yoke there which will wear out. Inspect.
14. Inspect rear & front spring condition, if you have reference ride height when new, you can use it as reference for today's condition, how much sagging is occuring.
15. Measure thickness of front and rear rotor. Their useful life is only like 2mm, that is it. Actually brake calipers are serviceable when the repair kit is available, no need new one.
16. All of your cooling and oiling system hoses or plastics/rubber hose or pipe, inspect them well and best to replace them all.
17. Test and calibrate all of your fuel injectors.
18. Inspect vacuum pump, make sure it still can produce negative pressure and how fast it can achieve the maximum negative pressure.
19. All plastic and rubber fuel hoses from tank to engine, replace them all. I wonder if diesel version W212, is the fuel tank output to engine using the blue plastic hose ? Gasoline one uses that blue plastic hose.
Now you wonder, is it worth all above for 50,000 miles and 5 years more of use ?

That's a long list! And a good one.
I'll go through it. Thank you.
Some of those items don't apply to the diesel obviously, but most do.
My car is still driving great - but, you are correct that it probably doesn't make sense to do all of that!
/
Last edited by mfab; May 7, 2025 at 09:35 AM.

01. All engine mounts
THIS IS A HARD JOB ON AN E250 4M. NO ROOM ON PASSENGER SIDE. Might be end of life for the car (for my ownership).
02. Tranny mount
MUCH EASIER DIY THAN THE ENGINE MOUNTS.
03. All for dampers/shock absorber and the top mount plate/bushings and the bump stop foam/rubber.
04. Front suspension control arms and the L shape ball joint if it does use it.
ABOUT TO DO THIS TO ADDRESS SOME VAGUENESS UNDER HEAVY BRAKING
05. Tie rod end the short one and the long one, this is the steering system.
06. 2 of bushings at the rear wheel carrier / knuckle
07. Rear spring arm bushing at the rear subframe
08. The propeller shaft ( main drive shaft ) middle bearing and boot.
09. 4 of rear subframe mounts , if it already sunk too much and differential bushings at rear (2) while at it and differential mount at front (1).
10. Rear suspension arms, 4 of them ( spring arm no need ), you need to inspect . 4 wheel alignment as in rear camber reading can help to figure it out.
11. Wheel alignment can show the camber and caster value of front 2 suspension arms geometry.
12. The rear tire wear pattern so far ( perhaps 3 - 4 sets of tires consumed already ? ) will be a good database.
4th SET OF TIRES. RUNNING MICHELIN 4S. OUTSTANDING TIRE! I DITCHED THE RUN FLATS.
13. 4matic shaft out of the rear of the G7 tranny, there is a yoke there which will wear out. Inspect.
14. Inspect rear & front spring condition, if you have reference ride height when new, you can use it as reference for today's condition, how much sagging is occuring.
15. Measure thickness of front and rear rotor. Their useful life is only like 2mm, that is it. Actually brake calipers are serviceable when the repair kit is available, no need new one.
ROTORS ARE NEW. Calipers are original and they're fine.
16. All of your cooling and oiling system hoses or plastics/rubber hose or pipe, inspect them well and best to replace them all.
17. Test and calibrate all of your fuel injectors.
18. Inspect vacuum pump, make sure it still can produce negative pressure and how fast it can achieve the maximum negative pressure.
19. All plastic and rubber fuel hoses from tank to engine, replace them all. I wonder if diesel version W212, is the fuel tank output to engine using the blue plastic hose ? Gasoline one uses that blue plastic hose.
Now you wonder, is it worth all above for 50,000 miles and 5 years more of use ?

I ended up installing a Continental belt. I've used them on multiple cars and they are good quality. The belt change is simple (15 minutes) and inexpensive ($25). When you're in there inspect/spin the tensioner, pulleys, water pump and alternator. A belt change is a good way to do a health check on those systems. Put the old belt in your trunk in case of emergency.
I'm going to spend some money now to refresh the suspension: front control arms (both), rear tie rod link (the support rod), and probably front struts.
From there I'm going to see how it goes. I'm not an expert, just trying to figure it out as I go!
Good luck.
/
Last edited by mfab; May 8, 2025 at 11:31 AM.
I ended up installing a Continental belt. I've used them on multiple cars and they are good quality. The belt change is simple (15 minutes) and inexpensive ($25). When you're in there inspect/spin the tensioner, pulleys, water pump and alternator. A belt change is a good way to do a health check on those systems. Put the old belt in your trunk in case of emergency.
I'm going to spend some money now to refresh the suspension: front control arms (both), rear tie rod link (the support rod), and probably front struts.
From there I'm going to see how it goes. I'm not an expert, just trying to figure it out as I go!
Good luck.
/

- Motor Mounts (I had the dealer do this). It's a hard job on the E250 4Matic. They split the subframe when they did it.
- Rear Subframe replaced under warranty. Rust. There is an extended factory warranty on the rear sub-frame for rust! Get yours inspected.
- Transmission mount (relatively easy job for me).
- Front differential, rear differential, center transfer case fluids all changed.
- I also replaced one of exhaust sensors and used my Foxwell 530 to force a DPF filter regeneration. No check engine lights.
Car drives great now. Very happy. I don't know the exact mileage off-hand, but it's in the neighborhood of 170K.
Up next is regular oil and transmission fluid change.
/
Last edited by mfab; Sep 8, 2025 at 06:37 PM.



