Oil for my 90 300d? - PeachParts Mercedes-Benz Forum

thekeene · #1 10-19-2010, 12:29 PM

Hello , I am considering switching to synthetic oil in my high mileage 90 300 d 2.5. Will this change from standard 15-40 rotella cause any adverse affects? Oil leaks? What oil would you recommend? The engine has cold lifter noise. Will this help the tap? Any help would be greatly appreciated. Thank you.

HuskyMan · #2 10-19-2010, 10:21 PM

everyone has their favorites, mine is Amsoil 15W40 marine diesel oil with a bypass filter installed. I've yet to see a diesel engine that didn't leak so don't worry about minor leaks. also, you might go through the top of your engine and check the valve settings, replace valve springs, replace the valve rotators etc. just to make sure everything is ship shape.

are you absolutely sure the noise isn't injector nailing? might be worth a stop by a mechanic for a quick listen to the engine before doing anything.

Hatterasguy · #3 10-19-2010, 10:31 PM

I love Amsoil Heavy Duty 15w40 diesel oil. I was running it in my old car for a bit, and now my friend has been using it in his E300D on a once a year oil change schedule. Its a tough oil with a high TBN, and holds up well. Also since its synthetic winter cold starting is not an issue. My uncle uses it in all his equipment, in a MB application its hardly stressed.

http://www.amsoil.com/storefront/ame.aspx

HuskyMan · #4 10-19-2010, 10:35 PM

I've run the 300DT on amsoil 15W40 for over 15 years and it just keeps on going. the valve train is clean as a new born baby's rear end.

vstech · #5 10-19-2010, 10:41 PM

a switch to a quality synthetic will not cause anything that is not already leaking to begin leaking IF you have been regular with oil changes, and your engine is in good condition.
if there is sludge in the motor, beginning a oil change regimen with synthetic will show you all the leaks you didn't know you had. the motor will be MUCH better off with clean internals and you will know what is leaking by finding all the places oil seeps out of.

I agree that having a qualified mechanic inspect the noise and servicing the lifters would be a good idea, and help you in many ways.
you have an engine that has a known issue with timing gears, be SURE you pull the valve cover and inspect the cam gear for wear. you want even spacing and tight teeth on the chain links. no points on the teeth!

Renntag · #6 10-19-2010, 10:46 PM

I am considering a change to Synthetic for our diesels. I am also considering installing an on board oil Centrifuge to help remove some of the soot. This will extend oil change intervals and hopefully make the oil a little cleaner.

vstech · #7 10-19-2010, 10:51 PM

Quote:

Originally Posted by Renntag

I am considering a change to Synthetic for our diesels. I am also considering installing an on board oil Centrifuge to help remove some of the soot. This will extend oil change intervals and hopefully make the oil a little cleaner.

have you got any plans for such a device?

TheDon · #8 10-19-2010, 11:00 PM

Quote:

Originally Posted by Hatterasguy

I love Amsoil Heavy Duty 15w40 diesel oil. I was running it in my old car for a bit, and now my friend has been using it in his E300D on a once a year oil change schedule. Its a tough oil with a high TBN, and holds up well. Also since its synthetic winter cold starting is not an issue. My uncle uses it in all his equipment, in a MB application its hardly stressed.

http://www.amsoil.com/storefront/ame.aspx

I thought you ran Mobile 1 synthetic?

I switched from a dino based oil in the cabrio to synthetic and the front main started to leak...

shertex · #9 10-20-2010, 06:53 AM

I think it would be difficult to go wrong with Mobil 5w40 Turbo Diesel Truck...as good or better than anything you'll find. You can get a gallon for $22 or so.

You should be able to move to fairly long drain intervals if you make the switch. FWIW on my 92 300D, when I did an oil analysis after 7500 miles, the soot load was only 0.8% (mixed driving)....all other measurements also well within tolerances. Since Mobil synthetic can handle 4% soot (though MB recommends no higher than 2%), I'm very comfortable going with 10-12,000 mile drain intervals.

John Schroader · #10 10-20-2010, 09:20 AM

I surely cannot offer any expert advice here, but can say that using Lucas oil additive has surely lowered my oil consumption. Running Rotella 15w40 and a bit of Lucas cut oil consumption from 2 qts. / 3K change to 1 qt. /3K change. Not sure if I'm doing the best thing, but it seems to work.

bobodaclown · #11 10-20-2010, 11:01 AM

Rotella T6 5-40 here on my 1992 W124 OM602. Change it every 5K. New oil/filter. All seems to be going well.