I purchased a 1998 E320 from Southern California. The car has used 20W50 weight oil since new. I live in the Chicago area and was told by my local mercedes dealer that they use 10W40 weight oil in the winter. Since the car's computer calculated 4000 miles since the next oil change, the dealer told me that the 20W50 weight oil is fine. The car has averaged 12 to 15K miles between oil changes (which is an entire year of driving for me), should I be concerned about driving in freezing temperatures with 20W50 weight oil or should I have the oil changed to 10W40 weight oil for the winter?

I would switch to 10-40 immediately. Cheap insurance for the very cold weather Chicago is experencing.

Gets pretty cold here (20 below or less). Dealer says to run 10w30 in winter and 20w50 in summer.
As well, I find it interesting that you are getting 12-15k MILES between oil changes. I do a LOT of hiway driving, and get about 10k KILOMETERS (about 6200 miles) between changes. This seems to be due to the dealer reseting the FSS counter to 8000km countdown intervals. My manual says it will be reset to 15000km. I questioned the dealer on this and they said that was incorrect and that there has been an update stating the 8000km figure. I realize the system is flexible and takes into account driving style, but that is a LOT of difference.
I am thinking the dealer may be feeding me some BS here. Anyone know about this ?

[This message has been edited by trent (edited 01-22-2000).]

Dont know about Chicago but I heard it canbe as cold as Toronto.When i went there few yrs back it was colder.
In TO ,we use 5w30 for winter,10w30-40 for summer.

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Tom 1992 300E 2.6

You guys have me wondering about my use of 15W40 year-round in my 84 SD. It got to 8 deg F about a week ago, I had forgotten to plug in my block heater, and my car really didn't want to turn over (took about 4 tries of cranking). It seldom gets below zero around here.

I'm considering using Shell Rotella T 15W40. My independent uses Castrol 15W40, but I'd prefer something with an CG rating at least. Another mechanic once told me that it's ok to mix oil brands, even viscosities; basically saying it doesn't matter.

Even if this is true I'd prefer to keep use same brand of oil. I understand Shell makes Rotella in a 10W40 but I haven't seen it for sale anywhere, and I've never seen a mail order source for oil. Sorry if this has been covered before.

[This message has been edited by Robert W. Roe (edited 01-22-2000).]

I just did the first oil change on my 99 E430 (5000 miles) with Mobil 1 15W-50 a couple weeks ago. Here in Boston, it's now in the single digits (F) and wind chill in minus double digits (F). I don't have any problem starting in the morning. I think the synthetic oil really does it job. Mobil 1 claimed the oil still pumps at (-38F).

Trent, The 15K mile oil change is quite unbelieveable, however the new FSS system is capable of oil changes up to 20K, per MBZ FSS brochure. Brochure MC-98-002-600 states:

"The mileage interval between required maintanance services is now a minimum of 10,000 and a maximum of 20,000 miles.*

It also states that the average oil change will be between 11,500 and 12,500.

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• 1998 MERCEDES-BENZ E430
  
• OBSIDIAN BLACK METALLIC/BLACK LEATHER
  
• XENON H.I.D. LOW BEAMS
  
• DEBADGED (E430 REAR)
  
• AMG CHROMED TIP DUAL EXHAUST
  
• CARLSSON 1/6 CHROME (PLUS 1) WHEELS
  
• SLK "WREATH" WHEEL CENTER CAPS
  
• ALPINE CHM-S611 CD CHANGER
  

I use Castrol GTX 10W-40 year round in all of my cars with no problems. I just changed the oil and filter in my 300SD a few days ago. The oil change before this most recent one left me stuck using Castrol RX 15W-40 which was ok, but I definitely feel that my cars run cooler and start easier with 10W-40 in them. We use QS 15W-40 at the shop all year, but if it were up to me, I would go for 10-40. Anyways, my $0.02


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Rgds,
Aaron Greenberg
MB technician
Precision Motorcars, Cincinnati, Ohio
'67 250SE Cabriolet
'77 450SL
'79 6.9 (SOLD)
'80 300SD
'85 380SE
'89 420SEL
'93 300E 2.8

This note is for Robert -

If you decide to go with Rotella, they are available as one gallon jugs in a case of six, enough for three changes for an SD.
Picked up mine at the local Sam's Club.

I would be a little cautious about using a diesel oil in a gas engine. Car and Driver's Pat Bedard had an editorial on oils a few months back. It seems diesel oils have additives that could damage catalytic converters. The E320 is a LARGE car with a small engine. Depending on how you drive I wouldn't stray from 20-50 convetional or 15-50 synthetic in the summer. I left the 20-50 in my wifes 740 BMW until after Christmas this year. We live in central Minnesota and it gets cold! When it came due for a service I switched to 10-40. Seems to turn over a little easier when its below zero. With the miles you drive I would go with 10-40 over the winter and 20-50 for summers. Change it twice a year, spring and fall. This will avoid any contaminant build up from lack of driving too.

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90 300GE 5sp
95 740iL

G-Man

My note was specifically directed to Robert, whose car is a diesel....
Actually, I didn't pay attention how us diesel heads got into this discussion originated by gas engine/oil post.
Whoops !

Thanks for all of your advice. G-Man your suggestion makes the most sense for me. I just put snow tires (Michelin Pilot Alpin) on my E320. What a difference from the summer tires (Michelin Pilot XTG V4) which are like racing slicks on compacted snow or ice. I plan to change oil weight when I change from winter to summer tires.

This subject has always confused me, probably because each person I've spoken to has a different opinion. What about very hot climates? I'm in Arizona where winter temp rarely reaches the 30's and summer temps sit around 110 for months at a time. How do you gauge the viscosity?
Jason

jason:

Congratulations!! You have discovered that on the subject of oil, EVERYONE has an opinion. Try getting help on an arcane subject, and very few will even bother to respond.

Anyway, when I lived in Glendale and drove at the track in the high desert, where temperatures of 110 are not uncommon, all of the guys in the club were using 20W50 with no ill effects. And since it is difficult (if not impossible) to find something like 10W60, you can do no harm with the 20W50. It will protect you at 110, and will not gum up at 32.

So good ahead, enjoy your MB without the Fear of Driving; it doesn't really matter what brand you use, as long as you change the oil every 3,000 miles.

See other posts (using the search feature for "oil", and you'll see 1000s more opinions.

Enjoy.....Andras

Everyone has an opinion is right. Mine is that 3000mi intervals are arcane. Modern autos run very clean and don't contaminate oil like they used to. I also have a new Ford diesel truck. On the Ford-Diesel website this subject has been beat to death. The fact is that oil analysis on these trucks has shown that up to 10,000 mi. intervals show little degredation of oil. Without a doubt gas M-B engines of recent vintage are much easier on oil than a diesel truck. On the other hand these are expensive engines and I personally go 5000 mi on my german machines. If I switched to a synthetic I would use the cars computer to determine intervals. Or as discussed earlier change when the climate dictates.

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90 300GE 5sp
95 740iL