I worked in the automotive parts business for about 25 years and sold a lot of oil. Many customers used Castrol 20w50 and so did I for awhile. A few years back I researched the SAE web site and saw that they reccomend no more than 20 points difference between the numbers on either side of the "W" in the oil's weight. I recently had our '99 E320 serviced by a MB certified mechanic who told my wife we had used the wrong oil (10w30). They put 5w40 in it. I thought an oil like that would be more suited for northern climates where there is extreme cold. In south Georgia do we really need an oil like the 5w40??

Thanks,
Bobby

I don't know if this is true or not but the way it was explained to me many years ago was that the lower number is actually what the real weight of the oil is and the higher weight is accomplished by the additive package and isn't really a real weight you can bank on under extreme conditions. That's why I put so much "weight" (I'm so funny) on the lower number.

The way it was explained to me is that they still don't know how to make a thick oil behave like a thin oil but they can make a thin oil behave like a thick oil when it needs to, at least for a little while.

I do know that the "W" stands for what the "weight" of the oil is in "Winter" conditions but again, my understanding is that this is also what the oil started out as before they pumped it up on additive "steroids". In fact, I was told that in many cases, a car is better off with straight 30 or straight 40 weight for this reason as long as said car is not started in cold temperatures.

The bottom line is I want a fairly thick oil in my pan because I live in a hot climate, M119s are hot running cars, and I also believe higher mileage cars need a heavier oil to fill the looser clearances of their higher mileage engines. On the other hand, I know I don't want to go too thick though because too thick of an oil robs too much power just for the pump to circulate it through the engine.

We've been talking about this and other oil issues here: http://www.500ecstasy.com/forums/showthread.php?t=6209
Regards, Eric
_______________

__________________
89 300E "Benzer1" 15.924 Uncorrected
93 400E "Benzer3" 14.200 U.C.
95 E420 "Benzer4"
92 300E "Benzer5" 16.299 U.C. Future turbo CNG
87 300D "Benzer7"
87 300D "Benzer8"
87 300D "Benzer9"
87 300D/70 AMC Javelin "Sidewinder-Benzer"
87 300TD "Benzer11"
06 E320 CDI "Benzer12"
05 E320 CDI "Benzer12A"
71 AMC Javelin AMX 401 "Sidewinder"
74 AMC Hornet 401 "C.K.10" 13.63 U.C.
74 Bricklin SV1 "Presto" AMC 360 pwrd.

Bobbo,

10W30 is strictly a GASOLINE Oil.
(Since you've neither listed your MB Type in your "Signature" or Public Info,
we've No idea what you're Driving)
[It MAY be a Petrol/Benzine/Gasser MB,since you're posting on the "Tech"]

Certain Diesel Rated Oils (5W40) are The Preferred Lubricant for both Diesel AND Gasoline Applications.
I.E. Mobil's Delvac 1, Redline's 5W40

'Where you be in Georgia (AKA,Who is the Dealer?) ?

__________________
'84 300SD sold
124.128

I wouldn't think.

__________________
1988 California version 260E (W124)
Anthracite Grey/Palomino
Owned since new and still going strong and smooth
MBCA member

Past Mercedes-Benz:
1986 190E Baby Benz
1967 230 Inherited from mom when she downsized
1959 220S Introduced me to the joys of keepin' 'em goin'

There are only 10 kinds of people in the world--those who understand binary and those who don't

http://www.startekinfo.com/StarTek/doclist.jsp

Lighter weight synthetic oils are best for 1998 & later cars!

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

As referenced, the correct oil for a 99 E320 is one that is on the MB 229.5 list. The most common one to find is Mobil 1 Synthetic 0W-40. In order to take advantage of the FSS or FSS Plus (Flexible Service System) extended service cycle (10K+ or 1 yr) built into the electronics of your car you need to use a 'special' fleece media filter as well. Using a paper media filter and/or other non 229.5 synthetic oils with FSS can result in sludge formation as it did in early MY98 before people knew better.

Make sure to use an oil that meets MB's 229.5 specs. (I think thats the most recent)

You can get Castrol 0w30 European formula pretty cheap and it meets those specs AFAIK.

If you use the FSS you absolutly have to follow this, or you will sludge up the motor.

__________________
1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Doc, first of all, thanks for your reply. What specific weight oil would you reccomend for the 99 E320 which, by the way CI is, a GAS engine. Even with my limited MB knowledge I know that much. And keep in mind we are in south Georgia where it gets hot in the summer and usually only cool in the winter except for a few days. However, we recently had a 2 week stretch of lows in the mid teens to mid 20's. Thankfully it has warmed up but today we had about a month or twos worth of rain. Again, thanks for the help!!

www.bobistheoilguy.com

All the information you could possibly want on lubricants by people in the industry or retired from the industry.

__________________
1993 190E 2.6 Sportline

I use synthetic 5W-30 year round, oil change every 5K miles.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

German Castrol ftw.

0W30 A3 rated full synthetic, essentially the same and only oils MB and BMW use (along with mobil 1 A3 5w30)

this oil is terrific stuff.

__________________
1992 850i 6 speed
1991 M3 S54B32 swap
2007 328iT/6 RWD sport wagon
1987 325E 330iZHP engine swap
2004 Vespa 200GT
1976 W115 240D getting a much bigger engine. 5.5L
1997 R129 SL600 5AT

< 10W30 is strictly a GASOLINE Oil.
<
well..... that isn't really accurate.
10w30 is 10 weight oil with similiar behavior to 30 weight when heated.
its still a 10 weight oil when heated according to my viscosity cup though so...
the specification you need to look at is the "service rating" such as cd,cg,sd, et cetera. use the service rating called for in the owners manual when using non original equipment oils. the rating includes within it breakdown temps, mechanical pressure rating of the oil film, detergent specifications, and some other more esoteric information that sounds rather gobblegookish if you don't speak tech on a regular basis.

as an aside, not all high mileage motors will benefit from a thicker oil. eg honda and mazda spark ignition motors frequently call for 5w30 and using a 10w30 will cause valvetrain failure due to lack of lubrication. yep been there done that dangit. (racing is a different world since we usually rebuild those motors every season, sometimes more often) also expect a decrease in fuel economy with thicker oil, after all its more work for the motor to do pumping that stuff and that means in my experience the driver tends to develop a longer right leg to overcome the loss in available power at a given throttle setting.

On recommendation, I have only used Delo 15w 40 in my Mercedes.

Using Delo 15 -40 in my 300se .
Surprising thing there is no more startup clatter of hydralic tappets ,which used to last a few seconds on cold starts.How??
mak