No. 1
Sea Foam Motor Treatment
This product definitely needs to be plugged on this board more often! It has been mentioned a few times (you can search Seafoam, but the correct spelling is Sea Foam), but I think there are lot of products that get talked about here and overshadow poor lil' Sea Foam.

Anyway, I bought 2 cans at my local Napa (check here for other sellers). Put one 16 oz. can in my nearly empty fuel tank and then topped it off. And then I put 12 oz. in the crankcase. Took it out for a 60 mile roundtrip (got some Zankou ), and when I got home I drained the oil. H.O.O. (Hot. Often. Overnight.) Put Delo in the next morning, and took it out for a spin.

At that point I'd logged 60 miles with Sea Foam in the fuel tank, and have fresh oil in the engine (Note: You don't use it as an 'ongoing' oil additive. You use it right before an oil change and then dump it.) Wasn't really noticing any dramatic improvements, but then again I never really noticed anything dramatic with LM or Power Service products, or Rotella DFA.

But, over the next few days I started noticing the following: Easier starts with less smoke, smoother idle, virtually no smoke while driving, and feels a little peppier! It's just good stuff. Give it a try!


No. 2
Mobil 1 Synthetic Gear Lubricant (75W-90)
This has been discussed quite a bit here, and I thought I'd give it a try. Thought about trying the full-synthetic Valvoline, but it was 3 bucks more per quart!

(Funny note: I started to drain the differential, and noticed that near-virgin gear lube was coming out! It must've been replaced right before I bought the car. I guess that's a good thing...)

Topped the rear off with the Mobil 1, and took it out for a drive. I didn't really have that much whine to begin with, but I did immediately noticed that whatever whine was there is now gone. Again, it's just good stuff. No reason not to run with it.

Two things to consider when putting additives in your car. Is it really worth the effort and money. Does it really accomplish anything. A lot of people used to put transmission fluid in the diesel. 1 quart per tank of fuel. It would "quiet down and clean the injectors" Yes it did quiet them down. Mercedes did a test on this and found that the tranny fluid actually caused the injectors to clog. So they recommended NOT to add tranny fluid. ( they do approve Chevron Techron as an injector cleaner)
Now on to your Sea Foam. It would be a shame to find out that is was actually ruining something in your engine, say 20,000 miles from now. When I bought our 99 E300. The dealler informed me of the FSS sytem. It checks the viscosity and cleanliness of the oil and tells you when to change it. Thank you very much, but I'll change the synthetic every 3000 miles. 2 years after I bought the car I got a letter from Mercedes extending my engine warrantee to 150,000. Due to a class action law suit over the FSS and non synthetic oil producing a coaking build up.
Be careful what you add to your cars lubrication and fuel system.

Second Synthetic differential oils. I will quote Stu Ridder, Technical Editor for the MBCA.

" No synthetic gear lubes are approved by Mercedes-Benz for the passenger car differentials. Specification for Service Products, Sheet 235.0 Lists many manufactures of GL-5 hypoid gear oil in SAE90 or SAE85W/90 that are suitable. Virtually any well known brand of hypoid gear oil will work well. We suggest changing it every 30,000 miles."

Mercedes has not approved synthetic hypoid gear oil. On a side note, they have tested all there engines for synthetic motor oil and ALL, BUT the 300SL Gullwing engine are approved. The seals in the 300SL Gullwing start to fall apart with synthetic. So I would hate to find out that your differential seals start to leak in 10,000 miles.

Use what's approved, change it often, and no "Snake Oils"

Dave

__________________
1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car

Is it possible that part of the improvement was the Zankou itself and have you conisidered adding IT to your car?....it's sooooooo good!

__________________
Richard Detoy
'84 300SD
'76 Moto Guzzi 850 Le Mans

rdetoy,

Yes, the car would probably run much better on Zankou garlic sauce! I know I run much better on it


dmorrison,

I was always taught to respect my elders. So I'll just politely say that your opinion is just that, an opinion.

There are numerous other board members that have tried/used both, and I haven't seen any posts screaming "that Sea Foam ruined my engine" or "that crappy Mobil 1 caused my differential to implode."

And regarding the magical M-B Approved Products List, it's just like the FDA -- a company has to submit a product to have it approved. If Mobil didn't take the time to submit its synthetic gear lube, it doesn't get Approved...