Any recommendations? Should I go synthetic?

Thanks!

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W123 1979 240D 224K (Southern Sloth)

I live in Mississippi, even south of you. I have always used Castrol GTX 20W50 in my '79 240D since it was new. Since my car is always garaged, I use this grade year-round.

This oil was one of the few approved by Mercedes in 1979.

As to synthetics, I believe that to be largely a matter of personal preference and opinion. While synthetics are superior in some ways, if you change your oil according to the schedule, i.e., 3,000 to 3,500 miles, it is my opinion that the extra money on a synthetic is something of a waste.

All right, guys. I have set myself up as a target. Let's see whose going to take the first shot.

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Ted
1979 240D

Thanks Ted!

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W123 1979 240D 224K (Southern Sloth)

Big topic here!! Get ready!

Anyways, I use synthetic in two of my cars, the 380SE and the BMW 745i. In all the rest, I use Castrol GTX 10W-40 year-round. I think it's the best medium. Unless you burn oil (in which I think the 20W-50 would be better), the 10W-40 is the best choice in my opinion. Synthetic is certainly good but in an old diesel with alot of miles on it, I'd just stick to regular dino oil. If synthetic oil had been around/popular when the car was new, I certainly think it would have offered superior protection to petroleum based oil, but I'm afraid that after alot of miles (especially on a diesel) it would start to use oil and would evenutally leak. I use synthetic in the BMW because it is very much needed in a turbocharged gasoline engine which is capable of high output and you definitely want to keep that turbo happy! Well, good luck! My $0.02


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Rgds,
Aaron Greenberg
MB technician
Precision Motorcars, Cincinnati, Ohio
'67 250SE Cabriolet
'77 450SL
'80 300SD
'85 380SE
'89 420SEL
'93 300E 2.8
'74 Jensen Interceptor Mk.III
'81 DeLorean DMC12
'85 BMW 745i Turbo

I have had good sucess with Mobil 1 15/40 in both of my diesels

Just my $.02...

I used 10W-40 until I passed the 400K mark and was smoking like a freight train...

I then switched to 20W-50 (actually my mechanic suggested it) and the smoking stopped. With the miles I have on my 240D, I use this grade year-round with no problems.

I have even began using it in the wife's 300D and the car runs great!

Like I said... My $.02 worth....

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William
76 240D - 545K miles
78 300D - 200K+ miles

Gone to Autozone for a case of Castrol GTX 20w50...thanks for the input!

Sloth,

Don't forget to examine the ratings on the oil you choose. There are S (spark ignited engines) and C (compression ignited engines). Ensure that the oil you select has a C rating for your diesel, such as CF, CG, CJ etc. SG, etc without a C rating have not been tested for use in diesel engines.

Good luck,
Change oil hot and change oil often,

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Larry Bible
'84 Euro 240D, 516K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

Thanks Larry!

Glad I caught this before I started!

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W123 1979 240D 224K (Southern Sloth)