603 Motor - Switch to Synthetic from Dino Steps
 

Thinking of switching to synthetic oil today to help keep the motor cooler in the desert climate this summer. I travel around 300 miles / day at 100 to 115 F* pushing around 3,200 rpm (long highway miles) for hours

Original SDL 603 motor with 351,xxx miles. Oil changed at approx 3k intervals for life.

I've heard that due to the synthetics cleaning (de-sludge) capability it is better to start with a 50% dino & 50% syn blend as to not break up too much crud that may lodge some where i.e. oil passage.

So any thoughts or experiences I might want to know?

Thanks

I went from dino to straight synthetic on both of my 200k+ mile 95 E300's without any issues.

It depends on previous service. If the oil has been changed on a regular basic of say every 3 to 6k with filter and good quality oil, then change to syn at next service. If oil is never changed just refilled when low, then don't change to syn at all. I think you get the idea. When I got my old 500SEL, I changed the oil when ever it got black. When I could check in the valve cover and it was clean, then I went to syn and have not looked back.
The 300D, I changed as soon as I got it at 290K miles. No leaks. No usage.

I hope this has helped in some way.

Paul
















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Just switch it and ride! Maybe do the first oil change at your normal 3-5k, and then you can get at least 8k out of it. I have been running 8-10k intervals and she is purring.

Very interestig thread! I was under the impression that it was reccomended not tk switch over older vehicles to synthetic...

If your car has leaks on regular oil, they may only be minor or nearly non-existent. But once you run a thinner oil which has detergents and is cleaner, it may reveal the already pending leaks. If you have failing gaskets and seals, synthetic oil will make its way out of them easier. The oil however did not cause the leak.

The switch is on - But what about filter change intervals
 

Thank you boys!

Oil has been changed at about 3,000 miles for the last 26 years...and there are a few minute leaks so if they leak more it's time to fix them.

So I'll switch today & hope the new stuff will help the old boy keep running for many more miles...

Wowa...for got something...do all you synthetic users still change the filters at 3,000 miles or so. I forgot about the soot build up factor!

thanks all!

... FACTORY recommendation on the 603 was 7500 miles between oil and filter changes...

you've been doing 3K the entire life of the car?

wow.

change to syn.
change the filter/oil every 10K and don't look back.

7500 miles service interval?
 

I had no idea.....the car actually sounds better (quieter) when I cange it at 3,000 but I guess I was just burning not only soot but loot.

Thanks again boys....great to have this group to steer through the fear of a little change

^x2

I changed the 80 240D to synthetic at 321K. had no previous service records from the previous owner, they Gave us the car with 305,906K.

Iam using 15/40w oil, didn`t leak before the change, and still no leaks.
Did the first oil change at 10K and filter at 5K. Oil usage hasn`t changed, about a qt every 12 to 1400 miles.


Charlie

is it burning or leaking? on a 3K oci, that's 2 quarts replaced... I'd worry about more than 1 quart in an oci... 1/2 would bother me.

Really? Not 5,000?

Last night we rolled 337,000 miles. You think this is an excessive amount of oil useage with these miles?

No oil leakage, well........ maybe a drop now and then. :rolleyes: engine is dry on the bottom side as well and the bottom side of the car.

Oil level stays about the same with around town driving and some freeway driving. It`s when taking a long trip and hours of pounding down the Highway it tends to use some oil, not any more than when using Dino oil.

Charlie

get ready for the oil leaks......