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I was wondering if anyone can give me a definitive answer about the kind of oil to use. I live in Chicago and it just snowed today, when it gets cold out my car starts fine but you can tell its running really rough (car vibrating and such). I run the car about 60 miles a day and it just seems like it never really warms up to smooth riding the entire time. I had 10w-30 full synthetic in there in the summer and just got an oil change today. I was going to put in 5w-30 full synthetic like I did last winter but after they drained my oil they told me they were out of it. They put 5w-40 in there for me.

How is this in comparison to 5w-30? I know that 5w flows better than 10w when its cold out and 40 flows less than 30 when warm but I think I am looking for a less visocisity all around since it's cold out--or will this not matter? It has 144k on it and i felt like the cold driving w/ 10w-30 was killing it..but theorhetically higher temperatures with 5w-40 would actually provide less flow less the 10w-30. I need some good advice on how the cold driving will be affected by the 5w-40. I have no problem changing the oil out to 5w-30 if anyone here is certain that it will provide for a smoother ride all around and that the 5w-40 will somehow adversely affect driving.

Also, I just noticed that some companies offer 0W oils. Would a 0W-30or40 be even better?

Any help is greatly appreciated.[/align]

 

OK>you've got two entirely different symptoms going on here it seems, at least by the way you describe it.
Let me explain. The car "running rough", not driving smoothly, etc. has nothing to do with the weight of the oil
you've put in it. Nothing at all. All the weight oils you mention from 0-30 to 10-40 or everything in between will be
fine in cold weather. Thin when cold, thicker when warm. OK. So, you're good with the oil thing. I would use Mobil 1
as the factory did, but there are comparable oils out there that are full synthetic that are all good. If the car isn't
"warming up" as you say in 60 miles, ummmm.........there's something else going on. It really has nothing to do with
the weight of the oil. The important thing here is to change it with a filter on a regular basis and you should be fine.
Anything else going on isn't oil related. Hope this helps.

 

Oh, and you also said the oil might "provide for a smoother ride all around".
You lost me on that one. The ride quality would not be affected by changing to any kind of oil.
Again, the oil and the ride are not related to each other.
If the car runs rough, best to diagnose and fix what's going on than to guess and waste money.
Just my opinion!

 

Mercedes do suggest Mobil1, and Its what goes in my 2001 C320 which now has 152,000 Mi on the clock, and still runs a quiet and smooth as anything.

OEM Fill is not Mobil, take a look at this.

http://www.fuchslubricants.com/auto_sectors.php?s=c
Its a German oil brand.

0w40 is an Excellent all round grade of oil, and it what MB will usually say should be used unless your driving in the Arctic.

Cheers

PS, I do agree with cayote that Oil grade and the actual ride should not be connected, unless ur firing on just a couple of cylinders

 

Just for the record, my '05 came from the factory with Mobil 1.
Sticker on the front radiator support from the factory confirms this.
Perhaps you have something different that has the German oil. Mine didn't.
Since the post didn't say what vehicle, I had no idea, but it really doesn't matter.
I'm sure they are both great oils. The important thing is to change it with a filter.

 

Totally agree, although like you I prefer Mobil 1, and its more widely available.

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