I know that's an incredibly generic question, but I came across another member's posting that stated that his oil leaks had disappeared after switching to synthetic, so I wanted to gauge any other w123 owner's experience with this possible phenomenon.
One of my first tasks with my new 82 300D is to ferret out as many leaks as possible. If synthetic oil helps contain general engine oil leaks, then that would be of great help.
Thanks.

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1982 Silver 300DT

I've never heard of Syn making them stop... typically Syn can make them appear as it runs cleaner.

Where are you leaking from? Many are pretty easy to fix.

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

It appears the oil is coming off the bolts from the oil pan itself. I have a new gasket and will replace it when I replace my oil this weekend. That will also give me a chance to spend some time underneath and see if I can find oil leaking from anyplace else.

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1982 Silver 300DT

The oil pump pan or the main oil pan? Mine appears to be doing the same when in reality it's the rubber turbo drain plug that's the problem.

I started at the top and worked my way on down. The Cam Cover gasket was a large problem as was the PS return hose and the ATF gasket. It appeared the Exxon Valdez had run aground in my garage.

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

It shouldn't really affect leaks.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

mine smoked more, burned more oil and leaked more with synthetic... of course it was 0w-40 though

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1980 500SE/AMG Euro
1981 500SEL Euro
1982 380SEL
1983 300TD
1983 500SEC/AMG Euro
1984 500SEC
1984 300TD Euro
1986 190E 2.3-16
1986 190E 2.3
1987 300D
1997 C36 AMG
2003 C320T 4matic

past: 1969 280SE 4.5 | 1978 240D | 1978 300D | 1981 300SD | 1981 300SD | 1982 300CD | 1983 300CD | 1983 300SD | 1983 380SEC | 1984 300D | 1984 300D | 1984 300TD | 1984 500SEL | 1984 300SD | 1985 300D | 1986 300E | 1986 560SEL | 1986 560SEL/Carat | 1987 560SEC | 1991 300D 2.5 | 2006 R350

Mine leaked more, but hey, I don't mind. I like working on my car. I just hate when they're expensive repairs, which, if you do the labor yourself, leaks should be pretty cheap as long as it's a gasket and not a cracked 603 oil pan. I still want to pull my IP sometime this summer and replace the bottom cover gasket. I'll need to resort to out tool loaner program for that tool.

Thanks
David

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2000 Honda Accord V6 137k miles

1972 300SEL 4.5 98k miles

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No it is not a stop leak. Using it from the start after break in may prevent leaks longer, due to the seals not getting hard.

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1981 300D 147k
1998 VW Jetta Tdi 320k
2001 Dodge Ram 2500 141k
1979 300D 234k (sold)
1984 300D "Astor" 262k(sold)
Mercedes How-To and Repair Pictorials
I love the smell of diesel smoke in my hair

I had the same leak, looked like the oil pan was leaking, in reality it's the front crank seal on mine (already replaced the lower pan because it was dented). I haven't gotten around to fixing it yet because I don't have to add more than a quart in 5k miles but I will eventually fix it I suppose. The only thing I've ever put synthetic oil in that already had a leak is a generator, the leak doesn't seem any worse or any better, I think you'll probably experience the same thing with your car.


Make sure you clean the screen on the oil pick-up while you have the lower pan off. Also if the crank seal is leaking it tends to throw a little oil over on the ac compressor on mine.

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1985 300D Turbo ~225k
2000 F350 (Powerstroke) 4X4, SWB, CC, SRW, 6spd ~148k
1999 International 4900, DT466e (250hp/660 ft/lbs), Allison MD3060 ~73k

i would tend to think that since synthetics tend to be thinner they would leak more readily.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

I though that the viscosity is fixed? IOW, 5W30 is 5W30 be it synthetic or non systhetic for a given set of temp? Shouldn't the flow rate of 5W30 at say X deg Farenheit be the same whether it is synthetic or not? If not, how will it conform to the rating of 5W30?

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01 Ford Excursion Powerstroke
99 E300 Turbodiesel
91 Vette with 383 motor
05 Polaris Sportsman 800 EFI
06 Polaris Sportsman 500 EFI
03 SeaDoo GTX SC Red
03 SeaDoo GTX SC Yellow
04 Tailgator 21 ft Toy Hauler
11 Harley Davidson 883 SuperLow

you may be correct.

but look at what is available in synthetic 0w40, 5w40 these are viscosities that are not available in non synthetic.

i dont know if a 20w50 synthetic would leak more readily than a 20w50 non synthetic. i suspect it might. dont know for sure.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

I was talking about say Mobil 1 5W30 vs regular 5W30, Basically similarly rated oils. I suspect the leaking is because the oil is has more detergent properties and removes some of the sludge build up in between the gaskets.

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01 Ford Excursion Powerstroke
99 E300 Turbodiesel
91 Vette with 383 motor
05 Polaris Sportsman 800 EFI
06 Polaris Sportsman 500 EFI
03 SeaDoo GTX SC Red
03 SeaDoo GTX SC Yellow
04 Tailgator 21 ft Toy Hauler
11 Harley Davidson 883 SuperLow

Someone once wrote..

" Taint leaking...it's marking it's territory."


.

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[http://languageandgrammar.com/2008/01/14/youve-got-problems-not-issues/ ]

"A liberal is someone who feels they owe a great debt to their fellow man, which debt he proposes to pay off with your money."

See above...

'Could it be that synthetic is a smaller molecule than mineral?