I have a 1985 300D with 189,000 miles. I currently use the Rotella non-synthetic oil available at Wal-mart for about $6.25/gallon. I change my oil and filter every 3,000 miles. My car does not burn any oil. I have no trouble starting the car in the winter (the coldest it gets in Richmond, VA is about the 20s). I recently found a CAT dealer which sells the Mobil Super 1300 15W 40 full synthetic oil for $11.30/gallon.

I know that generally synthetic oil is better than regular oil but I don't want to start a new debate on whether this is true for an older engine. However, because of the relatively low cost of switching to the Mobil, I am giving it some consideration ($12.50 per oil change vs. $22.60 per oil change) Any thoughts? Also, would 15W 40 be the weight I need?

Thanks for any advice.

Scott

Scott,
Welcome the forum.
Oil discussions have been plentiful, extreme and very well covered. The best thing to do is use the 'search' feature and draw your own conclusions. Not to snub you, just helping you to get a feel for this site.


thebern

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1982 240D 313,000 (4 speed)
1984 300CD 172,483
1985 German Shepherd Dog -Lacey- R.I.P.11/04/05

Hood Stars, Wrist Crowns and Obsession Dobs

Scott -

Am not an oil expert. However, I've never seen a synthetic Mobil Super 1300 15w-40. What I have seen is Delvac 1300 15w-40, a dino diesel oil which costs about $6 a gallon.

What I use in my VW TDI diesel is Mobil Delvac 1, a 5w-40 oil considered to be one of the top synthetic oils on the market (having used Rotella T syn in my MB, I may soon switch to Delvac).

The stuff is hard, but is available at truckstops, oil distributors, CAT dealers (ask for rebranded 5w-40 syn) or online (www.avlube.com ?? comes to mind), for about $80 for a four-gallon case.

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'91 300D 2.5 Turbo 330K
'00 VW TDI Golf, 190K
'67 BMW R50/2
'73 Norton Commando Interstate

Go withe synthetic. I use Delvac 1 and stretch out my oil changes a little bit. to 10K kilometers vs. the 7K kilometers asper the factory recomendation. MBZ uses Mobil1 as the factory fill.
Mobil 1 is available at Wal-mart is a very good oil!!
It will make your car start much easier in the winter.

Steve
Near Toronto Canada, it was -3F this morning
1987 300SDL 389,000 Kiliometers

scott! hey fellow richmonder. i live here in richmond as well. i just asked my mechanic when my 85 300TDT was in about switching to synthetic, he vehemently dissuaded me from doing that. he said it would leak a lot more often and rattled off about 10 other reasons not to switch to synthetic. he said if the car were newer, like post '95 i should think about it, but not the w123 diesels.

send me an email sometime - estarr@starmail.com

maybe we can get together and chat if you want

eric

__________________
1995 E320 Sportline Wagon "Bernard"
black on black leather

http://i.imgur.com/BdZ7jM3.png

Peyton300TD

Your mechanic might do well to do a little research and catch up on the times. The older synthetic oil formulas did eat gaskets but that is no longer the case. Many have reported reduction in oil consumption.

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"