Changing to Synthetic - PeachParts Mercedes-Benz Forum

Jorn · #1 12-11-2003, 02:54 PM

I like to change to synthetic, what is the right procedure to do it.

Thanks

janko · #2 12-11-2003, 03:07 PM

literally drain and fill. some though here to change at regular interval - 3000k - for first time after switching. something about superior detergent package found in synthetic. hope this helps. a search will yield reams.

gsxr · #3 12-11-2003, 07:00 PM

Yep - drain & refill. I'd strongly recommend using Mobil, Amsoil, or RedLine synthetics, in either 5W-40, 15W-40, or 15W-50 weights. Do not use SynTec, Rotella Syn, or Delo Syn. Wouldn't hurt to change the first time at 4-5kmi since it will clean some crud out. After that, you can probably go 5-10kmi (get an oil analysis to verify the safe limit).

And yes- do a search!!

Jorn · #4 12-11-2003, 07:27 PM

Thanks you guys; I did I small search before posting, but I have to admit I'm a little lazy. @;^)

#5 12-12-2003, 01:55 PM

I have heard that switching to synthetic on motors with high miles can lead to leaks. Unfortunately, I heard this after I switched. No problems, yet. Unverified wives tale.

gsxr · #6 12-12-2003, 02:14 PM

Mostly wive's tale. Good synthetics (like Mobil-1) have additives that swell seals and can actually slow or stop some leaks. However if a seal has failed, and old dino oil let sludge buildup prevent oil from leaking past that seal, switching to syn can clean out the sludge and allow the leak to show itself. So syn won't CREATE leaks, but it can make them show up where they were hidden in the past. IMO, there are too many benefits to NOT use synthetic, and if you have leaks, just FIX them!

Scott98 · #7 12-12-2003, 02:16 PM

Quote:

Originally posted by Orkrist
I have heard that switching to synthetic on motors with high miles can lead to leaks. Unfortunately, I heard this after I switched. No problems, yet. Unverified wives tale.

How many miles did you have on your car when you switched? How much have you driven since then? I've got 235,000 miles on my '97 and am thinking about switching to synthetic.

Scott

gsxr · #8 12-12-2003, 02:19 PM

I switched all my cars to Mobil-1 15W-50 (or Delvac-1 5W-40) when I bought them, at 189kmi, 204kmi, and 229kmi. No problems, but I did see benefits... quiet valve lifters, cleaner internals, better MPG, easier cold starts, etc... YMMV...

Rick Miley · #9 12-12-2003, 02:20 PM

Scott - don't think twice about it. Make the switch. Your OM606 will love the stuff.

Scott98 · #10 12-12-2003, 02:24 PM

I did use the final two gallons out of my case of Rotella oil last weekend. I guess the next oil change would be the perfect time for the switch...

Scott

punky · #11 12-12-2003, 02:53 PM

Got a '81 240d one year ago. According to maintence book it always had dino all it's life. I continued that until 137k miles and switched to Shell Rotella synth. Almost an immediate rear seal leak, not bad. A small wet spot 8" diam. under car every day. After about 1.5k miles leak stopped. Just switched 2 days ago to Mobil1 15w-50 at 140k. Will see what happens.

#12 12-12-2003, 04:40 PM

Scott98; I switched at 235K. Now its at around 236K. No problems and I'm not to worried about it. If it does start to leak, I'll just fix whatever is leaking without complaning considering how cheap this car has been overall.

I know from my MGs that synthetic makes a measureable difference in how a motor runs. I'm not a mechanic, so I won't try to get technical and look like an a**, but in my old MGs it improved oil pressure considerably. The MB starts easier when its colder and seems smoother and quieter, but how smooth can you get? Its hard to tell a real diff.

Jorn · #13 12-12-2003, 05:17 PM

Is Mobil1 15w-50 a good choice, have some starting problems in the morning, runs a little rough for 6 seconds?

gsxr · #14 12-12-2003, 05:21 PM

Mercedes has only approved two Mobil synthetic oils - Mobil-1 15W-50 and 0W-40. I recommend using the 15W-50 unless you live at the North or South Pole. Cheapest source is usually Wal-Mart, they sometimes have it five quart jugs (red cap) for about $22. Or wait for a sale somewhere and take advantage of Kragen/Shucks/Checker's 5% price guarantee, just show them the ad from the competitor's store and get an extra 5% off! I would do that at Kragen with a K-Mart sales flyer.

Jorn · #15 12-12-2003, 10:15 PM

Would Mobil1 15w-50 be a good idea, my 1978 300CD starts a little rough in the morning, runs smooth for the rest of the day. I live in LA.