Is 15w-50 too think for DC weather (not an oil war, I promise!)

[GregS]

I simply want to know when 15w-50 is acceptable for use. It is recommended in the manual for my '90 300CE as an all weather oil, as is 15w-40 and 10w-40, but it seems like it would be awfully thick unless you live in the desert (I live in DC).

The PO provided records with the car indicating oil changes with Amsoil 10w-30, but the owners manual states 30 weight is only recommended for temperatures under 50 degrees. The last oil change I did I just put in Chevron Delo 400 15w-40, because I couldn't find any synthetics locally in that range. Although, I did find Mobile 1 15w-50 at Walmart, so I am considering weather that is a good option. Another option is Amsoil 10w-40, but hasn't it been determined that 10w-40 has too many additives and that a 15w-x is preferred?

I don't mean to start an oil war, I just want to hear opinions on 15w-50.

Thanks,

GregS
'84 300D
'90 300CE

I've used 15W-50 Mobil 1 in my '91 300E in both Minnesota winters and Arizona summers. Remember that this oil has the same pour point as 10W-30 petroleum based oils. This oil was what Porsche told their owners to use before 0W-40 Mobil 1 was available in the U.S.

I think that you could use this oil all year round in DC. MB says you can use it down to 4F.

Also, MB has told their dealers not to use 5W-30 or 10W-30 Mobil 1. There's some doubt that these oils are true synthetics now.

I've been able to find (occasionally) 15W-50 Mobil 1 packaged in 5 qt. containers at Walmarts at a price of around $3.60/quart.

One more thing, Mobil puts more anti-wear addititives in 15W-50 than in their other weights.

[jsmith]

Originally posted by GregS
Another option is Amsoil 10w-40, but hasn't it been determined that 10w-40 has too many additives and that a 15w-x is preferred?

that applied to 10w-40 dino oil many years ago when the viscosity modifiers they used had a tendency to break down. i don't think that problem exists anymore. i put in 15w-40 delo late in the fall and this winter i wished i had used mobil 1 instead...

[manny]

An M-B mechanic told me very recently, that Mercedes-Benz is suggesting Mobil 1, 15W 40, in all their engines.
That's what I am using, since I figure, they should know their engines best.

[GregS]

Good info, thanks. 15w-50 has the same pour point as 10w-30? Hum; interesting. If that's true, then I guess I know what I'll do at the next oil change.

I guess my other question is if anyone is aware of a 15w-40 synthetic on the market. On the other hand, if the modifiers in 10w-40 are no longer an issue, than maybe the Amsoil 10w-40 is a good option (in addition to Mobile 15w-50).

Thanks, and remember, I don't mean to start brand war, I'm just tossing around viscosity vs. local temperature ideas.

Thanks,

Greg

Do you mean 0W-40 Mobil 1? This is probably the best choice for newer engines with the FSS system but it's hard to find. Other than an MB dealership, I think you might find it at Autozona.

[GregS]

I think he must mean 0w-40, because Mobil doesn't make a 15w-40. My owners manual only recommends a 15w or 10w, even in the coldest of weather, so I don't know if I'd feel comfortable using a 5w, let alone a 0w. Both of those weights seem too thin for the relatively warm temperatures we have here in DC.

Greg

Someone once took a look at the specs for 0W-40 and suggested that it was really a 12W-40. I

[mhingram]

I use 15w-50 in colorado year round.

[yal]

I use 15w-50 in New York year round.