Switched to Synthetic, Change Filter Early? - PeachParts Mercedes-Benz Forum

shertex · #1 06-03-2009, 10:03 AM

On the 91 300D I just picked up, the PO kept on top of oil changes, but always dino (usually 15w40). Sometimes 5,000 mile intervals, other times as little as 1,000 (she didn't drive it very much in recent years).

I just switched to Mobil 1 Turbo Diesel Truck 5w40. Even though there are only 78,000 miles on the car, and even though PO did regular oil changes, is it likely that deposits/crud has built up that the synthetic oil will loosen....and thus should I replace the filter after, say, 1,000 miles?

I've just never been clear as to whether the build up the occurs with dino happens only on really high mileage vehicles where perhaps oil changes have been neglected or also on vehicles like mine.

Thanks!

#2 06-03-2009, 10:07 AM

As long as the oil and filter were changed regularly there shouldn't be a build up of anything and with only 78,000 miles on the car you should have nothing to worry about. As far as I know any real build up is only a problem on negelcted motors.

pawoSD · #3 06-03-2009, 10:33 AM

Quote:

Originally Posted by helpplease

As long as the oil and filter were changed regularly there shouldn't be a build up of anything and with only 78,000 miles on the car you should have nothing to worry about. As far as I know any real build up is only a problem on negelcted motors.

I second this. At the very worst there might have been a "dino varnish" coating on some of the parts, that will get cleaned off. No need to replace the filter early though....just do normal changes. I usually go 4k between filter/oil changes using synthetic (thats on a 617 though)

winecountryone · #4 06-03-2009, 10:35 AM

If you plan on running extended drain intervals(10-12-15K miles or more)the folks at AMSOIL recommend changing the filter at the factory recommended change interval.
I haven't heard of any reason to change the filter so quickly after a changeover to synthetic.On a low mileage car with regular upkeep there should not be a lot of "crud" in the engine.
You can use oil analysis from companies like blackstone labs to determine when changes are needed but MB diesels aren't like Cummins/Detroit motors that hold several gallons of expensive synthetic.The truckers change it only when necessary due to cost(10+ gallons at 20$/gal for synthetic plus 40-50$ for a filter making a 250-300$ oil change

)

shertex · #5 06-03-2009, 10:51 AM

Quote:

Originally Posted by winecountryone

If you plan on running extended drain intervals(10-12-15K miles or more)the folks at AMSOIL recommend changing the filter at the factory recommended change interval.

I definitely plan on long drain intervals. With my 92, I've been going about 9,000. At 7,500, soot was only 1% and all the various trace elements were at very acceptable levels. The 91 is the same engine and with much less mileage.

pmckechnie · #6 06-03-2009, 12:03 PM

I will get flamed for this but I have to give my opinion. An 18 year old car with 78K miles on it averages 4104 miles per year, 342 miles per month. At 5000K oil changes that comes out to 14.6 months per change. That also comes out to one tank of fuel per month. One year on dino oil was way to long. It should be changed at least 2 times per year.
If I had just bought that car, I would use Mobil 1 oil syn and change the filter, AND the oil at 1000 miles for the first 2 or 3 changes. That should get it cleaned out and ready for a long life. I have a 91 D with K on it and it just got back from a 1000 mile trip and didn't use any oil and got 34 mpg average. I guess I go overboard when it comes to maintenance but I wouldn't be afraid to get in either of my cars and start out across country. Combined they have over a half million miles racked up.
Paul

uberwgn · #7 06-03-2009, 12:32 PM

If the previous owner was using a name brand diesel-rated oil, there isn't likely to be signficant accumulations of anything. It would be easy enough to inspect for crud under the valve cover should you have the desire to remove it.

Good luck with it!

pawoSD · #8 06-03-2009, 02:27 PM

Quote:

Originally Posted by shertex

I definitely plan on long drain intervals. With my 92, I've been going about 9,000. At 7,500, soot was only 1% and all the various trace elements were at very acceptable levels. The 91 is the same engine and with much less mileage.

Wow....the 602 must run a LOT cleaner than the 617.....the 617 is a soot machine!

Oil starts looking a bit *thick* if pushed past 5k....

shertex · #9 06-03-2009, 04:09 PM

Quote:

Originally Posted by pmckechnie

I will get flamed for this but I have to give my opinion....If I had just bought that car, I would use Mobil 1 oil syn and change the filter, AND the oil at 1000 miles for the first 2 or 3 changes. That should get it cleaned out and ready for a long life.....

Won't the filter catch anything of consequence? It seems like I'd be discarding perfectly good oil. Mind you, I'm perfectly willing to do it if it would be likely to prolong the life of the engine. But I'm just not seeing the rationale.

dieseldiehard · #10 06-03-2009, 04:41 PM

Quote:

Originally Posted by shertex

Won't the filter catch anything of consequence? It seems like I'd be discarding perfectly good oil. Mind you, I'm perfectly willing to do it if it would be likely to prolong the life of the engine. But I'm just not seeing the rationale.

Yes, the filter would catch anything of consequence
the only time I change a filter early is on a newly rebuilt engine or one that had extensive work done on it or the vac pump started leaving debris in its wake.
Just switching to synthetic I would not replace the filter early, just at 5K miles or more. I've pushed 7500 on synthetic (15W40 HD Marine by AMsoil) but only because I was on the road. I had an oil analysis done by Blackstone and they confirmed the oil was still acceptable. The 602/603 engines have very little soot, I believe that MB improved the rings considerably over the 617.

2.5Turbo · #11 06-05-2009, 04:04 AM

Quote:

Originally Posted by pawoSD

Wow....the 602 must run a LOT cleaner than the 617.....the 617 is a soot machine!

Oil starts looking a bit *thick* if pushed past 5k....

60x engines are a lot cleaner. I did an OA on mine at about 6500 miles on the oil and the insolubles came back at 0.3% with everything else well within the acceptable range. The report stated that the oil looked as if it had only been run for 4200 miles! Blackstone says I could run 10k on a change of M1 but I don't drive the car enough to get to 10k in a reasonable amount of time. I change it at 8k which happens to be about once per year.

LUVMBDiesels · #12 06-05-2009, 06:03 AM

Quote:

Originally Posted by pmckechnie

I will get flamed for this but I have to give my opinion. An 18 year old car with 78K miles on it averages 4104 miles per year, 342 miles per month. At 5000K oil changes that comes out to 14.6 months per change. That also comes out to one tank of fuel per month. One year on dino oil was way to long. It should be changed at least 2 times per year.
If I had just bought that car, I would use Mobil 1 oil syn and change the filter, AND the oil at 1000 miles for the first 2 or 3 changes. That should get it cleaned out and ready for a long life. I have a 91 D with K on it and it just got back from a 1000 mile trip and didn't use any oil and got 34 mpg average. I guess I go overboard when it comes to maintenance but I wouldn't be afraid to get in either of my cars and start out across country. Combined they have over a half million miles racked up.
Paul

Actually I am doing just that with my son's 'new' 1995 Acura. When we went to change the oil i noticed that the engine is filthy! I changed it to M1 in May and am going to change it again in July (about 1000 miles for him) Then we will do it again at 3000 miles before going to a normal interval depending on how clean the engine is then.

What I can suggest is that you really look at the exposed cam and valve train when you open the oil filler and see it there is a lot of crud in there. If there is, then do the multiple oil change thing, if it looks clean, then I would not worry about it and just go to extended oil changes with M1.

WD8CDH · #13 06-05-2009, 08:18 AM

I would run it to 5000 miles, pull a sample for a UOA and then make the decision on how much longer to go. I most likely wouldn't change the filter before the oil.