Oil weight
 

After years of changing oil and mostly using heavier weight oils, I learned something new this weekend. 20w-50 pours almost like mud, and 5w-30 pours almost like water.

I never realized the drastic differences. I have had higher mileage cars over the years, so I have used heavier oils. My preference, I guess.

This weekend, the CE got 5w-30 Exxon oil (never used that brand before).

I put Shell Rotella synthetic in the truck. She is driving mostly interstate, 70 miles a day. So I will go from 3k changes to somewhere around 7k. I'll try it any way.

I switched my son's 300e over to Shell Rotella a few weeks ago. It's under 4 dollars a quart at Wally World.

It seemed like I was changing someone's oil ever 2 or 3 weeks. I don't drive great distances, so I will keep conventional oil in my car for now.

but wow, the pours were interesting....

You should see 20W50 at 5 below during a Chicago winter. Looks almost like grease!

Throw a quart of Delvac 1 5w-40 or Mobil 1 0w-40 in the freezer along with a quart of 15w40 dino and 5w30 dino...

Mobil 1 flows, dino is pretty thick.

Lee, I recommend that you use Mobil 1 15W50 or 15W40 mineral oil in your 1989 300CE. If you ask a service advisor at the local MB dealer I think he'll tell you that 5W30 oil is too low a viscosity for that engine.

thanks, Fred.

I was just going to keep this weight in for the months of November-January or so.

I'll check my manuals and see if this is acceptable, otherwise, I will drain and re-fill.

I'll second Ferdman's recommendation, especially given that you live in South Carolina. 5w30 is just too light a viscosity. I live much further north from you, in Toronto, and I still wouldn't use 5w30 dino oil. I run 10w30 in the winter, 10w40 in the spring and autumn, and 15w40 in the summer, all dino.

Jonathan

Man you guys make a mountain out of this, just run 5w-40 or 0w-40 all year round. Heck I was running 15w-50 last winter and sub zero temps didn't affect starting at all.

AFAIK MB specs Mobil 1 0w-40 for all its cars.

Hmmmmm........Oilthread = Comedyhour. :D

I agree with you, Hatterasguy, about Mobil 1 being the way to go. But I'm a little concerned about switching my 11 year old M104 over to a synthetic. I'm nursing a very slight head gasket leak, and I'm worried about the synth potentially clearing out any grit/crap in the seals that might be keeping my head gasket problem at the minor seepage stage. I've seen this happen on plenty of older cars and I don't want to take the chance on mine. Hence my switching of viscosities through the year with the dino oil. If I was running synth, I'd just run 5w40 all year and forget about it.

I agree with this idea. I've used 15W-50 in my 300E since I bought it new and it's worked great in both Minnesota and Arizona. However, you can no longer get it because Mobil has changed 15W-50 to something that's got even more additives so they can claim it's good for 15,000 miles.

I also have a new E320 so I've decided to use 0W-40 Mobil 1 in both cars. 0W-40 Mobil 1 was developed for Porsche and is now considered THE oil for high performance European engines.

I should add that Mobil 1 20 and 30 weight oils are petroleum based despite being called synthetic. Go with the oil Mercedes recommends (0W-40) and you are good no matter where you live or what you drive.

Oil viscosity--seems we've seen the topic before. My own practice has been just to RTFM and do what it says; I assume that the MB engineers knew more about the topic than I do. The Benz does well (at 166k miles) on the 20-50 that the manual suggests, and the Saab on the lighter oil that's specified for it.

Bah it still has the same API ratings. Seems like pretty much the same stuff. I have zero reservations about switching any engine regardless of age over to synthetic. If its in good shape you won't have an issue. If its full of sludge from 50k oil changes then you may have problems, but heck you already do in that case.:D

Considering that I can run 15w-50 in my old diesel for 7k-8k miles according to the lab a new gasser should be good for over 10k, or once a year.