Which oil to use? - PeachParts Mercedes-Benz Forum

bnzpwr · #1 08-06-2008, 12:56 AM

Hey everyone quick question, about good ol motor oil. I have been using 20w 50 in my 300SD. I live in So Cal. I get my oil changed every 3k-3500 miles (try to get at 3k but sometimes just dont get around to it). This last time i changed my oil my car started running much better. Seem like it had more "pep" and that the turbo seemed to spool faster and just performed overall better. I have 215K on original parts.

Which is the best motor oil to use? Sombody recently reccomended to me that I use a brand called "rotella" designed for diesels which I wouldnt need to change for 10,000 miles. is this true? what do you guys use and how frequently do you have it changed?

(I did a search and I didnt find a straightforward thread on this basic but important topic)

#2 08-06-2008, 01:02 AM

No, 10,000miles is far to long to go on a non-synthetic oil.

3-5,000k miles is fine for dino oil and you can push up to 8,000 if you use a good quality synthetic (not rotella).

The oil brand does not matter. What matters is that it has a Cx rating on the bottle. Most 15W-40 and 5W-40 oils have that rating.
http://www.calsci.com/motorcycleinfo/API.html
http://www.api.org/certifications/engineoil/categories/upload/English_Oil_Guide.pdf

If you want to know what brand of oil to use, search the forum. Its a fiercely opinionated subject and there is no bad oil as long as it meets the C rating.

86560SEL · #3 08-06-2008, 01:03 AM

My uncle uses "Rotella" in his 98' Dodge 3500 diesel truck and my other uncle uses it in his 85' Ford F250 diesel and his old 95' GMC Suburban diesel.

The 84' Mercedes 190D I just bought had the service records with it and the PO had been using Rotella in it for years. Not sure if its any indication, but looking down in the cap, it still looks like new in there... maybe that typical for a diesel anyway?

There are many opinions on oil usage however.

Quote:

Originally Posted by bnzpwr

Hey everyone quick question, about good ol motor oil. I have been using 20w 50 in my 300SD. I live in So Cal. I get my oil changed every 3k-3500 miles (try to get at 3k but sometimes just dont get around to it). This last time i changed my oil my car started running much better. Seem like it had more "pep" and that the turbo seemed to spool faster and just performed overall better. I have 215K on original parts.

Which is the best motor oil to use? Sombody recently reccomended to me that I use a brand called "rotella" designed for diesels which I wouldnt need to change for 10,000 miles. is this true? what do you guys use and how frequently do you have it changed?

(I did a search and I didnt find a straightforward thread on this basic but important topic)

Gurkha · #4 08-06-2008, 01:08 AM

Oil analysis shows an average life of six months or 6000 miles for HDEO like Delo 400 or Delvac Super MX and therefore you can use either of them till 5000-6000 miles.

bnzpwr · #5 08-06-2008, 02:27 AM

Quote:

Originally Posted by ForcedInduction

No, 10,000miles is far to long to go on a non-synthetic oil.

3-5,000k miles is fine for dino oil and you can push up to 8,000 if you use a good quality synthetic (not rotella).

The oil brand does not matter. What matters is that it has a Cx rating on the bottle. Most 15W-40 and 5W-40 oils have that rating.
http://www.calsci.com/motorcycleinfo/API.html
http://www.api.org/certifications/engineoil/categories/upload/English_Oil_Guide.pdf

If you want to know what brand of oil to use, search the forum. Its a fiercely opinionated subject and there is no bad oil as long as it meets the C rating.

Thanks for the links. I am not really picky about which brand to use. frankly I dont have much of a brand loyalty (except MB of course) but rather want to use what is most practical and economic.

I hope I dont sound too stupid, but I really couldnt get much info out of those charts other than the fact that there are many types of diesel motor oils.

Should I be using 5w-40? 15w-40? 20-50? Orrrrrr...are any of these fine as long as it has one of the C(x-#) things printed on the bottle?

#6 08-06-2008, 02:33 AM

15W-40 is most common for non-synthetic diesel oils.
5W-40 is what most synthetic oils are.

If an oil is one of those two weights its most likely diesel rated.

Gurkha · #7 08-06-2008, 02:38 AM

Depends on where you live, for temps lower than 0C, I would go for 5W-40 only and that means costly synths like Delvac-I or Delo Synth.

winmutt · #8 08-06-2008, 10:39 AM

RotellaT is 5w40 and is cheaper than M1 or others. It's what I use in all of my cars.

Scott98 · #9 08-06-2008, 11:08 AM

I would look for somthing that has the ZDDP additive package. Our engines are flat-tappet engines and oil without this package accelerates camshaft wear. I am currently switching all of my vehicles over to Redline because of this.

Scott

Kpmurphy · #10 08-06-2008, 11:09 AM

I use Mobil Delvac 1300 15W40 Diesel oil

Scott98 · #11 08-06-2008, 11:17 AM

BTW, Redline uses a Polyol Ester base stock which most other synthetics don't. Ever seen the Mobil 1 sponsored Porsche race cars? They use Redline.

http://www.redlineoil.com/

wenzee · #12 08-06-2008, 11:59 AM

I use Rotella SAE 30 all summer

my 300CD "Ela" loves it.

Will change to Rotella SAE 15-40 as temperatures drop below 50 F this fall.

winmutt · #13 08-06-2008, 12:17 PM

Quote:

Originally Posted by wenzee

I use Rotella SAE 30 all summer

my 300CD "Ela" loves it.

Will change to Rotella SAE 15-40 as temperatures drop below 50 F this fall.

I sincerely doubt that SAE 30 is Cx rated. If it isn't it wont like it for long.

bnzpwr · #14 08-06-2008, 02:27 PM

so...

It seems like the majority of you recommend that i use 15w-40. How important is it that it has a Cx rating on the bottle? To be honest iv never noticed it so it may be hiding in plain sight.

I live in So cal btw

Kpmurphy · #15 08-06-2008, 02:49 PM

Quote:

Originally Posted by bnzpwr

so...

It seems like the majority of you recommend that i use 15w-40. How important is it that it has a Cx rating on the bottle? To be honest iv never noticed it so it may be hiding in plain sight.

I live in So cal btw

I was told just to make sure you all ways use oil that is made for diesels.
It has a higher rate of detergent in it, that cleans the engine.
Over the last 21 years my dad used regular Castrol 10w30. I started using Mobil Delvac 1300 15W40 Diesel oil and I got a bunch of dirt in the bottom of the oil canister. I was told the diesel oil has a higher rate of detergent, and that is wait we need.
http://mbca.cartama.net/showthread.php?t=26013