Synthetic Oil Suggestions and where to buy - PeachParts Mercedes-Benz Forum

alamostation · #1 11-29-2007, 06:35 AM

It is time for oil changes on the diesels. I've never put synthetic oil in any of my cars before.

When I bought my MR2, it had synthetic oil in it and I got 33+ MPG. After seeing the usually pegged oil pressure guage in Guderian, I was worried about the middle of the guage oil pressure in the Toyota (turned out later that is where it is supposed to be), so I went with the owner's manual dino oil suggestion when I changed it. MPG dropped to 28-29. I will go back to synthetic soon.

Has anyone noticed improved milage from using synthetic oil in their diesel?

If so, what brand and where can you buy it?

muleears · #2 11-29-2007, 07:20 AM

Boy, are you opening a can of worms

There are as many opinions on this topic as there are members.

Personally, for my own simple reasons I use the following oil: In the 98 I use Shaeffer super 7000 10-30, it is a synthetic blend reasonably priced and available locally for me. It is also on the list of Mercedes approved oils for my car. I change it every 5K mi. and have an oil analysis done every 10K to keep track of things. In the 87 I use Rotella T 15-40. It is a spare car and doesn't get driven much anymore (note the mileage in my sig.) Changed every 6mo. or so.

Hope this helps.

kerry · #3 11-29-2007, 09:00 AM

Shell Rotella synthetic. WalMart.

#4 11-29-2007, 09:08 AM

The best available: Mobil Delvac 1 5W-40. Also branded as Mobil 1 Turbo Diesel Truck 5W-40. Same stuff, different name. Available at Most Medium/Heavy duty truck stores and at Wal-Mart.

Rotella "synthetic" is not a true synthetic, it is a dino-oil cracked to have properties similar to real synthetic oil.

bodyart27 · #5 11-29-2007, 09:34 AM

Mobil 1 Turbo Diesel Truck blend. WalMart is getting pretty good now about carrying them in the 4 quart jugs. Don't wait to the last second to find it, they don't stock a ton of the big jugs.

spugeddy · #6 11-29-2007, 09:41 AM

So far Mobil 1 has been the best for me.

I am not going to buy the Rotella Synthetic again. It increased my engine sound immediately after putting it in, and has noticably changed the "feel" of operation to me.

That might sound crazy, but it was like a light switch. I will probably use the Delvac next.

I have been using the synthetic for my whole ownership, so I don't know the MPG difference if any...

pawoSD · #7 11-29-2007, 11:56 AM

I am actually switching "down" to Rotella Synthetic 5w40 and will be changing it a little more often. Just comparing the dipstick of our diesels with M1 to the Rotella is interesting. The M1 seems to get "thicker" looking and pitch black, while the Rotella stays a lighter color and you can see the stick through the oil on it....even after 2000+ miles. It seems retain a lighter/more liquid property to it as well, while M1 seems thicker after time. Soot control differences perhaps? Our 300D runs awesome on the Rotella.

TwitchKitty · #8 11-29-2007, 12:17 PM

Check the caps on the oil at walmart before you buy. I have seen a couple now with broken seals and wouldn't put it past some low-life to pour cheap oil in the jug and return it for a refund.

Either the mobil 1 5w40 or the rotella 5w40 should allow your engine to outlast you, something else will have to kill it.

Check the DIY links for more information than you have time to read.

F18 · #9 11-29-2007, 04:40 PM

Modern dino oil or synthetic is all good if it is diesel rated.
Never noticed any change in mileage either way on my diesels.......but synthetic does make your wallet a little lighter....less weight.. better mileage may be

What ever makes you feel happy!

Hatterasguy · #10 11-29-2007, 08:43 PM

Put some Delvac 1 in Hurrying Heinz!

Styler_Colfax · #11 11-29-2007, 08:51 PM

I went with the 15w-40 Rotella T
I like it....also went with a little lucas for the cold starts

pawoSD · #12 11-29-2007, 09:51 PM

Lucas Products make the oil foam and starve parts of oil. Bad idea. I'd drain it right back out.

Oil additives = bad.

If it gets cold I'd really recommend using the 5w40 rotella, it flows WAY better in the cold and helps the engine with those cold starts and minimizes wear.

But as for that lucas junk.....I highly recommend NOT using it, all it does is make the oil foam up, it will not help cold starts/flow at all.

bustedbenz · #13 11-29-2007, 10:32 PM

Just for the record, I noticed this in the original post: Mercs are the only cars in my experience that consider pegged oil pressure "Normal". Nearly every other car on the planet, that I've looked at, has a reasonable gauge that displays right in the middle - within a "Normal" range. Why mercedes didn't put a gauge in that would go up to the pressure being used by the engine is beyond me.