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Garage => Mechanicals => Topic started by: Neil4speed on 27 February 2022, 01:28 AM

Title: Evaluate my 450 SEL 6.9 Tune Up Shopping List
Post by: Neil4speed on 27 February 2022, 01:28 AM
Hello All,

Hope everyone is keeping safe and well. I am looking to do a large 'tune up' on the 6.9 I procured a few months back. The car actually idles and revs reasonably well, but I am looking to do some deferred maintenance on the vehicle. I am referencing the manual for much of this but happy to hear what might be good modern alternatives. I have done a search and am picking suggestions as posted previously as well.

Oil Change - Filter + 11L of Oil  - I have been told by the previous owner that they used Mobil 1 in the vehicle but planning to switch over to MoS2 Anti Friction Motor Oil (10w-40) as per 'dad' Ken.

Automatic Transmission/Torque Converter Fluid + Filter - ~9L Liqui Moly Top Tec ATF 1100 or FUCHS A/T FLUID, MB236.14 - Thoughts on the two? Liqui Moly is a bit hard to get in Canada.

Rear Axle/Differential 1.3L Liqui Moly HYPOID GEAR OIL (GL5) SAE 85W-90

Hydropneumatic Suspension 6.0L FEBI ZH-M Hydraulic Fluid

Power Steering Fluid 1.4L + Filter LIQUI MOLY Top Tec ATF 1200 or FEBI Power Steering Fluid

Front Wheel Hubs 2.1oz X 2 Liqui Moly LM 50 LITHO HT

Brake Fluid 0.5L Any quality DOT4 Fluid...?

Coolant 16.0L I plan on doing a flush using daantjie approach listed here:, and then using some HEPU/MAXXUS G11 Phosphate free coolant MB325.0. Alternatively easy to us Zerex G05 Phosphate Free 50/50 Prediluted. I am debating as a precautionary measure (due to the hard availability of parts) to do a session of Liqui Moly Radiator Cleaner before I replace the fluid.

Replace All 'torpedo' Fuses in Fuse Box Heard it is a good preventive action that may prevent misdiagnostics. Planning on getting Flosser fuses from Ebay.

Spark Plug Wires + Spark Plugs DENSO 6718129 or NGK 54342 - Any preference or should I match with my plugs? I know the plugs have many different opinions but was thinking of using NGK 7082 {#BPR5EGP} G-Power Platinum (as it fit the gap at .32) but understand OEM is Bosch WR-9-DC+ (7911) NGK BPR5ES (7734). My understanding is that it may be important to use a non-resistor spark plug...

Thanks in advance for any thoughts or feedback! :) Can't wait to get this one going this summer.
Title: Re: Evaluate my 450 SEL 6.9 Tune Up Shopping List
Post by: daantjie on 27 February 2022, 02:15 PM
Engine oil: I like any good brand conventional oil like Castrol GTX. Or a good diesel oil like Shell Rotella.   Grade 15W-40 or for you in AB maybe thinner like 10-40 will be good.
ZH-M yes for hydro.
ATF should be Dex III but you can get newer ones that are backwards compatible.   I run Castrol Dex/Merc.
Coolant yes for Zerex G-05.
Diff I run Fuchs Sintopoid 75w-85.
Brake fluid I run ATE Dot 4.
Plugs NGK BPES5.
Hub grease any good brand high pressure wheel bearing grease will be fine.
Power steering yes on Febi non synthetic.
I am sure other members will chime in and perhaps disagree with my choices 8)
Title: Re: Evaluate my 450 SEL 6.9 Tune Up Shopping List
Post by: Jan S on 27 February 2022, 05:39 PM
a few thoughts ....

- When replacing coolant, check all hoses and clamps
- do a power steering fluid flush to get all the old stuff out
- Replace the steering damper? It's cheap and easy and could potentially significantly improve the steering (depending on the condition of the current damper)
- Replace air filter and clean the air filter housing on the inside
- Replace the ignition coil? (depending on how old the current coil is)
- Lubrication
- Check for vacuum leaks
- Check the K-jet system
- +++
Title: Re: Evaluate my 450 SEL 6.9 Tune Up Shopping List
Post by: Neil4speed on 28 February 2022, 11:05 AM
You two are such great support for the members here. Thank you!

My west-coast friend, thank you, I appreciate the feedback. You saved me from buying a resistor-type plug, so I will get those NKG's. The end goal is to get this car to you and get our cars together since separated from Stuttgart in 1977 (I am #2170) and have a drink!

Thanks, Jan very much for the response. I will make sure to inspect all of those clamps. I have added the flush/and Damper to the shopping list. Forgot to mention the air filter, but will replace it. The Coil luckily is in good shape (as new). Question on lubrication comment... is there a hit-list of spots? I can figure the logical ones... hinges/sunroof, doors etc.

Title: Re: Evaluate my 450 SEL 6.9 Tune Up Shopping List
Post by: Jan S on 28 February 2022, 07:03 PM
Depending on the state of your sun roof, cable and motor etc - an option is to take out the sun roof and thoroughly clean the rails, gliders and the cable and lubricate with special Mercedes sun roof grease (for the rails and gliders). The cable requires normal grease. Maybe the engine needs some grease as well.

And the sun roof switch at the dash can be opened, sanded (to remove corrosion), cleaned and lubricated with electrical lube.

It's not a difficult job, but it takes some time. And it can make a huge difference when opening and closing of the sun roof.

Mine was stuck, but works fine now.

General lubrication is also on my list, especially the electric windows.