Switch to syn oil at 215K miles ? - PeachParts Mercedes-Benz Forum

quickster · #1 05-09-2008, 07:17 AM

Do you think my car would benefit by switching to full syn oil with 215K miles already on it? I asked a couple of friends and they think that it would be a waste of money, and possibly start some leaks. But if I switch I could go a little longer between changes? Just wanted to run it past this forum. thanks

RUN-EM · #2 05-09-2008, 07:24 AM

Changed to synthetic at about 160 K. Did it at first by 1/2 synthetic and 1/2 regular oil. Then pure synthetic. No leaks detected. Can go a little longer between changes.

Regards

Run-Em

#3 05-09-2008, 07:29 AM

Switch it, no need to blend (Never blend oil yourself).

It will increase your MPG slightly, the engine will last even longer, starting will be easier (especially in the winter) and you can easily go 5-8k miles between changes if you use a real full synthetic (Not the fake Rotealla "synthetic"). The oil leak thing is a myth.

300SDog · #4 05-09-2008, 07:42 AM

I *used* to advocate high mileage conversion to synthetic..... Converted the 300SD to synth at about 260k miles - spun rod bearing less than 20k miles later

probear · #5 05-09-2008, 07:47 AM

Switched my F-350 with 100K and my 87 SDL with 147K and no problems at all. F-350 now at 176K and the SDL just rolled 200K

Brian Carlton · #6 05-09-2008, 07:58 AM

Quote:

Originally Posted by ForcedInduction

Switch it, no need to blend (Never blend oil yourself).

It will increase your MPG slightly, the engine will last even longer, starting will be easier (especially in the winter) and you can easily go 5-8k miles between changes if you use a real full synthetic (Not the fake Rotealla "synthetic"). The oil leak thing is a myth.

You can go 5K between changes with Rotella synthetic on a 617. Oil analysis shows the oil to be just about at the 1% soot point at this interval and all other parameters are still within acceptable ranges. If you want to go 8K, I'd go with a group IV synthetic. The soot loading will be considerably higher at 8K.

#7 05-09-2008, 08:39 AM

I agree, 5K miles with Rotella synthetic is no problem.

Brian Carlton · #8 05-09-2008, 08:48 AM

Quote:

Originally Posted by 300SDog

I *used* to advocate high mileage conversion to synthetic..... Converted the 300SD to synth at about 260k miles - spun rod bearing less than 20k miles later

..........yep, must have been the synthetic oil that caused the rod bearing to fail.............

vstech · #9 05-09-2008, 08:53 AM

Quote:

Originally Posted by 300SDog

I *used* to advocate high mileage conversion to synthetic..... Converted the 300SD to synth at about 260k miles - spun rod bearing less than 20k miles later

... what were the oil change intervals before this on the car? was it EVER run low on oil? did the oil cooler lines ever fail before? I believe you are in the minority of problematic synthetic changers...

LUVMBDiesels · #10 05-09-2008, 09:07 AM

I converted the 300SD to 'fake' Rotella T Synthetic and it worked very well. When the engine failed it was NOT due to oil.

The engine was clean enough to eat off of inside.

I converted the 300SDL from dino to the same Rotellt 5W40 and the oil leaks went away. I think the synthetic has the property of swelling the gaskets back up to the original size.

If you do convert to syn, I would do a few 2500 -3000 mile changes at first as the synthetic oil will be cleaning the gunk out of the engine.

My oil change schedule is this:

In the beginning:

Change oil and filter

1500 miles change filter add a quart of oil to replace what is lost in the filter

3000 miles change oil and filter

After six or so cycles:

Change oil and filter

2000- 2500 miles change filter and add a quart

4000-4500 miles change oil and filter

mobetta · #11 05-09-2008, 09:18 AM

I switched @ about 285K, no issues. the only difference is my car will start @ -10 w/ no block heater now. w/ dino rotella, it would only start down to about 5*F

quickster · #12 05-09-2008, 10:44 AM

I don't know the car's history, but I do know it was dealer maintained. The car is tight; no oil leaks anywhere(knock on wood). I'm going to give it a try with the synthetic. First I have to find it. Napa, Autozone, and Pep boys don't carry it. Around me, that is.

vstech · #13 05-09-2008, 11:39 AM

napa can order it for you.
so can pep boys... most wallyworlds are carrying it now too...

charmalu · #14 05-09-2008, 12:52 PM

I switched to synthetic some where over 300000, don`t remember exactly. I do know the engine ran so much smoother. I may have had a few drips of oil before the change, but changing to synthetic didn`t increase the leaks.

I did have the timing chain break at 330940 miles, but was unrelated to the oil.

as far as the synthetic loosening up gunk in the engine, isn`t the filter there to catch all this gink

. if the oil has been changed on a regular basis, there shouldn`t be a lot of gunk.

the syntheric I use is Amsoil 15/40 Marine Diesel, and I use the Amsoil full flow by-pass filters.

my 2¢ worth.

Charlie ☺

pawoSD · #15 05-09-2008, 01:51 PM

We changed all of ours over at 225k, 223k and 260k....and they've all been fine.
Changed our minivan over at 91k, and my uncles cavalier when it had 118k on it. All fine.

I use Rotella Synthetic but am paranoid so I change it around 4k instead of 5...I do a lot of city driving too....so more frequent is probably better.