1970 Mercedes-Benz 300SEL 3.5L Oil Recommendation

[OilMagnate]

This is a customer's project car that he wants to restore. We were assigned the task of getting it running before he dumps any real money into it. It turns over fairly easily, just needs a fuel pump (that was a nightmare to find, ended up using an MSD pump for an LS engine). I know domestic and Asian oil choices, but I'll admit I'm way out of my league regarding European vehicles. The customer wants an oil change once it can reliably start. Based on some quick research, I believe this thing holds 7.9 quarts, and I'm wildly guessing it takes a Euro XW-40 oil...? Is there anything that would satisfy this old engine while not breaking the bank? Does it HAVE TO be a European oil, or can I use a typical XW-40 (for example NAPA's $2.29/quart conventional oil starting in May)? I also assume NAPA's ProSelect 21398 filter will fit?

Sorry if the questions are ignorant, but that's exactly what I am regarding European vehicles...

Thanks for any advice!

 

[OM605]

I'd pick any cheap 40 with a 3.5+ HTHS. A cheap 10W40 or 15W40 (or even 20W50 for summer driving) would be my pick however you might consider a 0W40 or 5W40 depending on how cold it gets in OK for year round use. These old V8 are notorious for pitted cams and a very long timing chain that tend to stretch if OCIs aren't kept short. 3K OCI definitely applies to these engines.

EDIT : Use OEM/Hengst/Mann/Mahle filters.

 

[Pelican]

I would check in the owner's manual or with a "GOOD" MB indy as there were NOT any oils xxW40 when it was built.
Consequently passages may be too small for a W40 weight. I'm not certain that's why it's better to check.
There was a mechanic on U-Tube up the pacific N.W. that specializes in these vintage, do a search.

 

[OM605]

I would check in the owner's manual or with a "GOOD" MB indy as there were NOT any oils xxW40 when it was built.
Consequently passages may be too small for a W40 weight. I'm not certain that's why it's better to check.
There was a mechanic on U-Tube up the pacific N.W. that specializes in these vintage, do a search.

What do you mean? Back then we only had 15W40 and 20W50 in europe.

 

[kschachn]

I would check in the owner's manual or with a "GOOD" MB indy as there were NOT any oils xxW40 when it was built.
Consequently passages may be too small for a W40 weight. I'm not certain that's why it's better to check.
There was a mechanic on U-Tube up the pacific N.W. that specializes in these vintage, do a search.

No.

 

[edyvw]

That engine absolutely heavy oil. Wal Mart has Mobil1 15W50, but anything can go there. European vehicles were on W40 oils all the way until 2000’s. Even today they prefer that.

 

[Chris142]

I would check in the owner's manual or with a "GOOD" MB indy as there were NOT any oils xxW40 when it was built.
Consequently passages may be too small for a W40 weight. I'm not certain that's why it's better to check.
There was a mechanic on U-Tube up the pacific N.W. that specializes in these vintage, do a search.

My dad used 10w-40 back into the 60's that I know of.

 

[bluesmokertdi]

This is a customer's project car that he wants to restore. We were assigned the task of getting it running before he dumps any real money into it. It turns over fairly easily, just needs a fuel pump (that was a nightmare to find, ended up using an MSD pump for an LS engine). I know domestic and Asian oil choices, but I'll admit I'm way out of my league regarding European vehicles. The customer wants an oil change once it can reliably start. Based on some quick research, I believe this thing holds 7.9 quarts, and I'm wildly guessing it takes a Euro XW-40 oil...? Is there anything that would satisfy this old engine while not breaking the bank? Does it HAVE TO be a European oil, or can I use a typical XW-40 (for example NAPA's $2.29/quart conventional oil starting in May)? I also assume NAPA's ProSelect 21398 filter will fit?

Sorry if the questions are ignorant, but that's exactly what I am regarding European vehicles...

Thanks for any advice!

here is a service manaual dated from 2001, PRIOR to the "lifetime" fluids fantansy, note oil viscosity charts

http://assets.mbusa.com/vcm/CAC_RAPMD/02approvedserviceproducts.pdf

you cant go wrong with any modern 15w40 or 20w50

 

[JHZR2]

46EDA1C1-0D61-4712-83D9-CFFEA6BE42C7.jpeg

• JHZR2
• Mar 28, 2021

CE80C8B8-BFC4-458F-99DC-A80C8BC75761.jpeg

• JHZR2
• Mar 28, 2021

Id look at running an HDEO, at least once you have verified that it will run. Reality is you’ll probably need to do a few changes because of age, time, likely fuel and moisture dumping in when trying to get it running, etc. I run 5w-40 synthetics in my 40 year old diesels, and it can aid in cranking. But 15w-40 will be fine too to get the thing running, if that’s the most cost effective. That said, that might be step 2, and you might want something thinner to start.

Really right now if you’re just trying to get the thing runnning, and there’s a chance of it not, and a chance of lots of parts straining, the best bet may be to use the cheapest 5w-30 you can find, to minimize viscous losses, and get new oil flowing as much as possible. Then dump it as soon as it idles reliably, and go from there.

 

[Trav]

The first thing I would do is pull the plugs and put some oil in the cylinders with an oil can leave it overnight then crank it with the plugs out and fuel and ignition disabled.
I would use a cheap 5w40 diesel oil like Supertech to initially run it then switch it out to Mobil 1 Turbo Diesel Truck 5w40, it has everything this engine needs regarding zinc, phosphorus. 5w40 is not an issue with these old MB engines, they didnt have it when it was made so it is not going to show up on any recommendation chart for it but I have run these old timers hard on 5w40 HDEO without issue and its cheap enough.

Robot or human?

www.walmart.com

 

[2EHA]

just use a 229.5 oil

 

[Astro14]

I would check in the owner's manual or with a "GOOD" MB indy as there were NOT any oils xxW40 when it was built.
Consequently passages may be too small for a W40 weight. I'm not certain that's why it's better to check.
There was a mechanic on U-Tube up the pacific N.W. that specializes in these vintage, do a search.

There were lots of XXW40 and XXW50 back then. The owner's manual recommends both.

This engine will do well on either weight, but as was mentioned, the long timing chain requires an oil that is shear-resistant. Anything meeting MB 229.5 would be fine.

 

[Zack1978]

Interesting note about the fuel pump. I "thought" that MB will sell/produce parts for every and all cars they have ever made. I am not saying it will be cheap, but supposedly you can get any part you need. Is that true?

 

[2EHA]

Interesting note about the fuel pump. I "thought" that MB will sell/produce parts for every and all cars they have ever made. I am not saying it will be cheap, but supposedly you can get any part you need. Is that true?

yes they will find a way to produce NLA parts if you’re willing to pay up.

they also have the most consistent and easy to understand parts numbering system of any manufacturer