5-50 vs. 15-50 - which is better?

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May 28, 2002
My car doesn't distinguish between the 2...seems like both are acceptable. Which is better to use? Or are they roughly equal (assuming both grades are synthetic)?
I would say the 15W50, since there should be fewer Viscosity Index Improvers to shear back and eventually become useless sludge molecules floating around.
If I ever form a rock band I'm going to call us the Useless Sludge Molecules!

I agree, the 15w50 would be the better choice. I don't think any 5w50 on the market would hold it's viscosity very well at all, not unless it's using some super amazing (for lack of a better term!) base oil, which would in turn be very expensive.

If you really want to start running a 5w oil in your BMW, you should go for a 5w40.
Patman To all intents and purposes Mobil 1 here is 5W50. Its everywhere. M1 10W30 I've seen at distributor but nowhere else. I'd like a Pacific Peso (A$) for every 5 litre jug sold here, i'd would be rollin' in it very quickly. Pretty cheap too (A$42 jug). No 15W50 here unfortunately.
Does anyone there that runs 5w50 do oil analysis on it?

Up here the only 5w50s I know of are Syntec and Canadian Tire synthetic, but both of them are group 3 oils.
Yeah, I've tried both Delvac 1 and Havoline Synth. 5-40 with good results. My owner's manual specs. a 40 weight up to 30 C only (86F?). Not that we have to worry about that now, but over this temp, it recommends a 50 weight...and it does climb over this temp. freq...(in July
Also keep in mind that a good 40wt synthetic oil will offer hot temperature protection better than a 50wt conventional oil would too though.

On a local radio station:

"Now in the top 40 review here's the Top Group, with Patman, and the
'Useless Sludge Molecules!'

Let's see, who on this board would play the various instruments?

[ January 29, 2003, 11:26 AM: Message edited by: MolaKule ]

Originally posted by Patman:
Does anyone there that runs 5w50 do oil analysis on it?

Up here the only 5w50s I know of are Syntec and Canadian Tire synthetic, but both of them are group 3 oils.

A few years back, Esso ( imperial oil ) produced all the lubricants for Canadian tire. Esso still produces a line of gasoline synthetic oils, in the viscousities 5w30, 10w30 and 5w50. They are PAO based lubricants like they were before. They haven't moved to group III.

I know on this forum some people have concluded that Shell now produces the lubricants for Canadian tire, but has anyone found any proof that this change was made? Shell doesn't even make a 5w50 synthetic, so I'm not sure where this theory is coming from?

Also regarding the product being a group III, is this only theorized because of the belief that canadian tire now uses Shell to produce the product, and shell moved to using group III oils?

Canadian tire also sells a diesel oil (0w30 synthetic blend), that is rated CG-4. This product was really ESSO's XHD diesel synethic blend. Both products are only rated CG-4, and have not been updated. Here also Shell doesn't have a similar product. I think this is still the ESSO product. I believe Canadian tire has picked up another supplier for its cheaper autolab oils, but the main products, I still are create by Esso/imperial oil, since the specs for the products still match the line of imperial oil products.
Hey sprintman, can you send some of the M-1 5-50 to Canada...I'd love to try it!
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