I have a new E320 and asked the dealer about synthetics and was told they don't recommend it because of cost. I figure it costs something under $.002 per mile to use it versus regular oil. In any case, the dealer uses 20W-50 all year. I''m in Tucson, AZ where winters are lows inthe 40s and June-September are highs in the 100s. Even for here this seemed a bit heavy for a newer car so I called another dealer in Phoenix (same climate, maybe hotter), who uses 5W-30.

The MB manual has no info I can find on recommended oil weights and nothing about synthetics. Any input appreciated. In my other cars I have been using Mobil 1 0W-30, per Mobil's recommendation, for cars that the manufacturer says to use 5W30, and changing oil on the car manufacturers schedule (7500 miles).

What year E320 is it? Are you sure your owners manual says nothing about recommended oil weights? My experience with oil changes is that how often it is done is just as important as what it is done with. Switching to Mobil 1 on a car with 6 digits on the odo may not be a good idea but if we are talking new then switching to synthetic after a reasonable break in period shouldn't be a problem.

Lee

I was looking at the Mobil1 web site yesterday pondering changing over to synthetic. It seems that the 0W30 is not optimal for where you live. I think it is more for very cold regions since it claims to flow very easily. Living in Houston where is pretty warm year around, I'm using 20-50Castrol. On the Mobil web, they show the insides of a BMW that went 1mm miles. THe claim is that the engine parts that they show layed out on the table were up tto the original specifications; pretty good marketing... I'm especially suseptible to stuff like that!

Lee; I'm curious what oil your using for your 500E. I'm considering switching to Mobil 1 15-50.

In general, I'm getting the picture that regular oil changes, just like our dads taught us, is key... the rest sort-of fits in the religion and politics category!

I think you may have it backwards Bud: Generally, the hotter the climate the heavier the oil weight. I use 5w50 Synthetic Castrol in my 420 SEL here in south Georgia. In the Summer, the temps are high 90's. My car uses no oil at all with 125k on it. The few extra pennies are good insurace in my view.

My E320 is a 99 with about 800 miles on it.

I have looked in the manual where the capacities and types of fluids are listed and for oil it says 8.5 quarts and use what is recommended.

I haven't gone over the manual page by page, but there doesn't seeem to be any other place that would have this info. Lots of places in the new manual you are simply referred to the dealer.

The manual won't tell you what specifically to use but does give you suggested weights given the temperatures you will be driving in. It is definately in the owner's manual.

As Mark said...this oil debate is turning into "politics and religion" debate. Generally the warmer the climate the heavier weight oil you can get away with using. That is why 0-30 works well in cold weather... My 91 300E with well over 100K miles seemed to do best on 20w50 conventional year-round. QS 15w40 is what I have been running in the 400E. The 500E has perhaps the cleanest valvetrain I have seen of any car with any reasonable mileage and it has had regular changes with conventional 15w40. Since it seems to be thriving on that, I will not "mess with success". Winter doesn't get much below freezing and summers are 95+ F her in Atlanta. On something of the M103 generation the 20w50 might serve better in summer, but for the closer tolerances of the M119's the 15w40 works just fine. If I were to spend the extra $$$ for synthetic I would likely run Royal Purple. I have a family member who runs that in his 93 500E and has been very happy with it.

Each to their own....Lee

The specific info. may not be in the owners manuel. In my car, it was in a seperate sheet,or folder in the owners packet. Something in that " packet " will give you the info. you need. ( Please pardon my poor spelling.)

Talk about a subject you can 1000+ opinions on, this is it. Food for thought, how about the new M.B. AMG powered cars. Guess what oil they come with?? Mobil 1.
I race my Mercedes at least once a month, I use 5W40 synthetic oil. Wide open throttle for 50-60 minutes at 7000+rpm.

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MERCEDES BENZ MASTER GUILD TECHNICIAN
ASE MASTER TECHNICIAN
27 YEARS M.B. TECH

I checked with MBNA today and according to them, oil weight recommendations are not in the manual given with the 99 E320.

On the other hand, they were no help either. They siad that MB recommends not using synthetic oils and then allowed that Mobil 1 comes in the AMG engine cars. Then they siad Mobil 2 was OK, but other synthetics are not. They siad 5W-30, 10W-30, 0r 15W-50 were OK too. Back to square one.

Does anyone know what happens if you mix weights, e.g., does half 5W-30 and half 15W-50 give you 10W-40 or just a mess? :-)

Don't mix or "blend" oil yourself, there isn't an oil supplier in the world that would recommend it, and you will end up with a mess.

My 98 300 Manual to does not say much in relation to oil, I am thinking of making the switch to synthetic, maybe a call to Benz headquarters is in line here.

Mine is a 98 300E TD.

The latest issue of "The Star"( May/ June ) has some good info. on the subject, see the TECHNICAL TIPS section page 83. This is the same chart that was in the zippered package supplied with my 98 SLK. If your not a MBCA member and don't get "The Star" most dealers that I'm aware of have a few copies in their lobbies. This may be the specific info. your looking for.

I read that article, it says nothing about what oil to put in my car.

As a backyard mechanic, I can pretty well get by on my own, I just cant believe the company would leave out such important info such as this, especially when a diesel is involved.

However the Star magazine did have a somewhat good article on diesel, that is if you live in the states.

I'll offer my personal experience on oil.. I've used Mobil One in my 78 300CD since it had 10,000 miles on it.. it now has 285,000 on it, shows no sign of wear, runs perfect, and under the head cover is squeaky clean... no deposits or sludge. I've changed it every 3,000 miles or less and used everything from 5W20 to 15W50.. but prefer the lighter oils. The engine is so tight that when I occasionally used petroleum-based oils it was very sluggish until it warmed up. With the synthetic the starter spins it with gusto and I can start a cold engine down to below zero degrees at 6,000 feet altitude without a block heater... and it runs better the first few miles.. not so sluggish. Back in 1979 I wrote Mercedes and asked if Mobil 1 synthetic was an approved oil. They replied in the affirmative. Yes, it's more $$$, but for me I think it has been a good investment considering the $6,000 cost of a new engine and 17 years without a car payment. As for the wisdom of switching to synthetic on a high-mileage engine, there are a lot of opinions out there and I could not tell if they're substantiated or not. I would guess that if the engine is in good condition then there would be little harm in doing so. A lot of "wives tales" get propagated about oil as you know, but how much is sound wisdom is hard to determine.