Mercedes Diesel Fluids & Change Intervals 300-SDL

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Hey everyone, finally signed up as a member.

I bought a Mercedes 300 SDL Turbo Diesel a few years back and just got it running last year. The question I have is what type of fluids should I use in everything and how often to do the service work?

There is not much service information available to me and this is a list what I have done for maintenance in the past 1,000 miles since I got the car running.

Power Steering: Flushed out the Power steering and filled it up with a blend of the Lucas premixed fluid in the white bottle and topped it off with standard P/S fluid with some stop leak additive (considering Amsoil P/S fluid or Pentosin OEM).

Brake Fluid: Flushed the brake lines with Pentosin Dot 4 fluid as suggested by MercedesSource but have some air in the ABS pump. Found instructions online how to deal with that.

Transmission: Installed a new filter and filled it up with the Dex III sold at Wal-Mart in the gal jug for $12. I purge the ATF out the cooler line to dilute the oil in the TC, changed out about a gallon 3 times as a cheap flush because the fluid was awful as reported by UOA.

Engine oil: Been running Wal-Mart 15w40 and frequent oil drains to clean out the engine after replacing it with a used neglected engine, but it runs good. Just changed it to Rotella on the last service and plan to go with Mobil Delvac in the future.

Decided to buy engine oil filters from Amazon because they are European spec at a decent price (Mann, Mahale, Hengst). This is just better than going with whatever the local parts store can get, (Pure-O-Lator, Wix, STP) or some other over priced cheaply made filter.

Also added a Frantz Toilet Paper bypass filter system to this engine to clean up the solid particles that showed up on the UOA. This is a cool system and I replaced the Scott 1000 roll with blue Shop Towels. The flow rate is slower and that's a plus at trapping small particles.

Coolant: Did a flush of the cooling system, added the Napa branded coolant (Peak Extended Life) and added coolant boost sold by Amsoil due to the heat transfer coefficient. *Not sure if I need to buy better quality coolant for the aluminum head?

Rear Differential: The fluid is clear with a slimy feel to it as if it's 'top treated' with an additive, really don't know what oil is in it. Not planning to change it right away because the OEM oil is expensive and unsure what to get other than the Mercedes packaged oil.

I know this is a really long post, just looking for real opinions of when to change these fluids. The odometer quit working and I put in an hour meter to keep up with the running time. Any experience with Mercedes fluids will help me out because I am not sure what to use and all the mixed opinions all over the net complicates the problem.
 
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Do not over think fluids for that engine. Those engines are running on 15W40 the best. If you are in cold area maybe in winter switch to 10W40.
I would stick to Rotella 15W40 or Mobil 15W40.
 
I ran Mobil 1 TDT 5W40 in the 300D when I first bought it, it leaked it pretty bad but helped unstick my stuck rings, plus you'll have more luck starting it unplugged in winter. I hope your SDL doesn't have a 3.5 liter OM603 engine, got to watch the rods on those.
 
Originally Posted By: bullwinkle
I ran Mobil 1 TDT 5W40 in the 300D when I first bought it, it leaked it pretty bad but helped unstick my stuck rings, plus you'll have more luck starting it unplugged in winter. I hope your SDL doesn't have a 3.5 liter OM603 engine, got to watch the rods on those.

Its the OM-603 3.0 L with the weak head casting, the previous engine cracked the head before I bought it.

You are thinking of the OM 606 that has oil drain back problems and fills #1 with oil and bends the rod. People call it a rod bender. The other problem is the vibration shakes the oil pump loose in the 350 SDL.

I am running 15w40 in the engine but have no idea how often to change it or any of the other fluids?

The next project is to build the injectors, just looking for the time to get it done.
 
Originally Posted By: Dufus2
Originally Posted By: bullwinkle
I ran Mobil 1 TDT 5W40 in the 300D when I first bought it, it leaked it pretty bad but helped unstick my stuck rings, plus you'll have more luck starting it unplugged in winter. I hope your SDL doesn't have a 3.5 liter OM603 engine, got to watch the rods on those.

Its the OM-603 3.0 L with the weak head casting, the previous engine cracked the head before I bought it.

You are thinking of the OM 606 that has oil drain back problems and fills #1 with oil and bends the rod. People call it a rod bender. The other problem is the vibration shakes the oil pump loose in the 350 SDL.

I am running 15w40 in the engine but have no idea how often to change it or any of the other fluids?

The next project is to build the injectors, just looking for the time to get it done.


I would change oil in that engine every 3-5k.
 
Originally Posted By: Dufus2


Coolant: Did a flush of the cooling system, added the Napa branded coolant (Peak Extended Life) and added coolant boost sold by Amsoil due to the heat transfer coefficient. *Not sure if I need to buy better quality coolant for the aluminum head?

Rear Differential: The fluid is clear with a slimy feel to it as if it's 'top treated' with an additive, really don't know what oil is in it. Not planning to change it right away because the OEM oil is expensive and unsure what to get other than the Mercedes packaged oil.

Check this :

http://bevo.mercedes-benz.com/bevolistenmain.php?entercustomer=true&language_id=1


The cooling system takes coolants based on BASF G-48 or G-05 formulations (HOAT , low-silicated formulas, the latter is nitrite-containing too).Zerex should be easy to find.

http://www.glysantin.com/20-1-Engine-coolants-Know-how.html

http://bevo.mercedes-benz.com/bevolisten...chbegriff=325.0

The OAT coolants are "reserved" to MB heavy-duty range.(at least that's what MB say...)

This is a good read:
http://www.2phast.com/500e/techdocs/antifreeze_article.pdf
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The OEM diff fluid now is a SAE 75w-85 Fuchs oil (widely unobtainable):
http://www.generaloils.net/PI_TITAN-SINTOPOID-FE-75W-85_e.pdf

The car left the factory with a humble mineral GL-5 85w-90 or straight 90 oil.(open diffs. Not sure about what yours is.The OEM 235.7-certified 75w-85 is applicable to both open and LS diffs).

http://bevo.mercedes-benz.com/d/d/en/Spec_231_1.pdf



The former 235.7 OEM oil was BP Energear MBE 85w-90 (hen's teeth)

http://www.orthwein-oel.de/PDFs/Energear MBE.pdf

MB 235.7 category was introduced long after the car's manufacturing date and listed as backwards-compatible.Using this in a w126 or w124 would be an overkill IMHO.


If you have an open diff, any GL-5 xw-90 available will do...



The rod bender is om603.97x engine. The om606 is allright...
 
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If the gear oil is BP product, Castrol XXw90 gear oil would make the most sense to me, because Castrol is owned by BP.

That in mind, I highly doubt that car would be negatively afftected by simply using some XXw90 GL-5 oil.
 
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