1981 300TD Turbo. Oil and Lubricants.
 

I just bought an 81 300td turbo A/T. It was restored sometime 2004 and hardly moved after that.

I plan to change all the fluids and lubricants. All the benz guys I talk to tell me NOT to use synthetic oils. Something to do with the seals not being up to specs with synthetic oils. What gives? What oils and lubricants do you suggest for the engine, tranny, and diff?

I also noticed that the tranny's somewhat noisy. It was supposedly overhauled last year. The owner had the receipts for the parts he replaced. Nevertheless, here's a rattling sound when I run it. The noise becomes really loud when running it hard. I was doing 100kph earlier and it was too much to bear. Even the engine was too noisy.

Thanks in advance for your help.

Don't know who you've been talking to, but I'm using Mobil1 synthetic, and I do not have any leaks from my 83 300D's engine.

Regular oil works fine in the trans and rear end.

Have you checked the tranny fluid level?

Jim

Is it a manual or automatic? What kind of noise does it make?

As to the oil, lots of folks will advocate for synthetic here. They will about run forever with dino oil though. There is some thought that the synthetic will be more likely to leak and I tend to think that myself. Mainly use diesel rated oil in a 15w40 or straight 30w and you will be fine.

Good luck

Tom W

Iam running synthetic in my transmission w/o any leaks. I switched over at 331000 and now have 338000 miles. shifts much smoother.

There as many opinions about which oil as there are forum members here.


Charlie ☺

They don't know what they are talking about. Synthetic oil works great in these engines.

I've used full synthetic for the last two years and I actually have fewer leaks now.

That's good to know because I wondered about leaks too!:D:juggle:

All Mercedes are authorized to run on synthetic oil except the 50's 300SL. Seals in the old engine cant tolerate the oil. Why this engine I don't know but that was the latest I read in the MBCA magazine.

I run dino oil in all my diesels and change them regularly. I run snthetic in the SL.

Dave

There is no difference to seals between synthetic and dino oils.

There are advantages to the synthetic oils, some feel it's worth the extra expense, some don't. I run it in all gearboxes, hydraulics, and engines, I like the stuff and have been running it almost exclusively for 30years. Never had a leak increase or start as a result of synthetic oil use.

If it leaks on syn oil, Mercedes' official stance was (might still be) that you have a leak, and syn oil will likely get through it in larger quantities as it doesn't thicken to molassis levels when cold and stop leaking the way that dino oil does.

The myth started back in the 70s, when the original formulations of synthetic oils didn't contain enough compounds to swell the seals equivalent to dino oils. Old seals without the elasticity to make up the difference would be prone to leakage when switched to syn oil. Same problem that we now have with ULSD and o-rings in injection systems.

Later formulations of syn oils (late '70s - early '80s) had the additive packages tuned/tweaked to emulate dino oils with similar seal swell rates, so this myth is out-of-date by about a quarter-century. Still, people like to be against anything just to have an opinion, so detractors of anything are easy to find.

Buy and run the oils you want. If it leaks with syn oil, switching back to dino oil will restore the leak/seal to what it was before switching according to Mercedes-Benz The Star article ~ 2002.

Tranny and engine oil are at a good level. Weird thing is, the noise disappeared! I have no idea how it happened. I'm just thankful it did.

I'm still changing all my oils and lubricants though as well as the brake fluids.

Hmmmm.... syn or dino......

Any reviews on Delvac 1 or Delvac MX?

What about ATF? What's the required rating? I heard it supposed to be Dexron 3. Is that correct?

Gear oil? Will any old gear oil do?

I like the Delvac 1, have been running it in my big diesels for 16years with great oil analysis at (extended) change/drain time.

The only oil I prefer to the Delvac 1 is RedLine, but too expensive when the engine takes 6gallons or more at a change.

Rattling noise can mean the flexplate between the flywheel and the torque converter is coming apart. In the two cases I've seen, failure was not catastrophic, except for the flexplate :) I did have to remove some broken bolts from the torque converter. When the flexplate tears apart completely, the torque converter stops turning so the car doesn't move. Pull tranny, replace flexplate, good to go.

Sixto
87 300D

I used to run dino oil in my 300D and have since started using synthetic. It used to leak a little oil but seems to have stopped. I don't know if the synthetic caused that.

Any diesel-rated oil of the proper viscosity will be fine for your engine. Dexron III ATF in dino or synthetic is what the transmission takes. I run the dino in mine and it's doing just fine.

Boost, welcome to da forum. Synthetic is fine to use. Do you have other diesel Benz's besides the TD? What lubricants are available to you in Manila?

Do you do your own car work or bring it to a mechanic? I know that non-dealer labor there is cheap but you really have to watch the parts you buy especially from Banawe. Just like in the US, I understand dealer work is quite expensive.

Post pics of the new ride.

This is my FIRST benz. I've been going to the benz shop near my house. Pretty good service. Its not an authorized service station or anything but they do fix all mb's.

Its been a steep learning curve. I'll post pics soon!

Thanks for the welcome!