Topic: 5 or 10W

[articsteve]

I should have posted the link for that Shell pdf but that was for the 3 grades of Quaker State.  Shell owns Quaker State and Pennzoil so in essence it is Shell synthetic oil.

I also read that USA Castrol syntec is manufactured by a third party.

The wear qualities of those Group 3 Castrol oils might be OK, but the concern I have for non PAO-Ester derived oils is the deposits left behind.  I have 2 Rotax motors with RAVE and if you don't use the Rotax suggested Shell 2 stroke PAO synthetic the valves will gum and stick without fail.

[yugrus]

Of course every application has its own proper oil...

[21Rouge]

I do wonder about this. Hondas use the 5-20 but why has Toyota not made the jump to such a viscosity? Both Japanese manufacturers produce 'small-tolerance' engines.

Ok I just asked my son who works for a dealer conglomerate that ownes and operates Toyota, Honda and Kia shops in southern Ontario he says their Toyota dealerships were sent 5W20 bulk last year but nobody thought about what that might do to domestics cars that are lured into the dealership on give away oil changes as a marketing strategy to get people into the show room. 

So although 5W-20 isnt mentioned in Toyota manuals it is very likely that such a viscosity would work fine in newer Toyota engines. It seems that Used Oil Analyses on engines using 5-20 are generally quite good.

[21Rouge]

Examples: At -20C Castrol Syntec 0w30 (made in Germany) is thicker then Mobil 1 5w30. In fact, it is thicker then M1 5w30 (or probably any other 5w30 oil) all the way from 150C down to -30C. At working temperature it is almost 40 oil.

On the other hand, Mobil 1 0w30 is thinner then M1 5w30 from cold up to about 30C, at which point they have very close viscosities while temperature rises.

I have a good supply of Castrol 0W-30 (made in Germany). And although I know this particular 0W-30 works wonders in VERY extreme cold, I feel better putting in the 'thinner' M1 0W-30 for my cold conditions. I know 5W-30 would be fine but I hold to the feeling that there is an advantage to using a suitable 0W-30 in the winter in the GTA. I have done a Used Oil Analysis on the GC and will on this M1 0W-30 for comparison purposes.

Strange as it may seem the 'thicker' German Castrol will be perfect for the heat of summer.     

[yugrus]

Strange as it may seem the 'thicker' German Castrol will be perfect for the heat of summer.     

Agree. I'm not going to criticize the oil classification system, but obviously it is sometimes misleading. GC’s HTHS (High-Temperature High-Shear) value is incredible 3.6, so it does not shear down to low-30 or even 20 in the heat as many oils do.
You're might be perfectly right in choosing M1 0w30 instead of GC for the winter. I guess I'm cheaping out, I bought M1 5w30 on sale recently, and that's what I'm going to use this winter.
I have very good UOA with GC from last winter; 10,000km. The oil saw some low temperature extremes, and turned out to be very good fit. I'll do UOA with M1 5w30 this time and then compare the two.

[21Rouge]

Strange as it may seem the 'thicker' German Castrol will be perfect for the heat of summer.     

Agree. I'm not going to criticize the oil classification system, but obviously it is sometimes misleading. GC’s HTHS (High-Temperature High-Shear) value is incredible 3.6, so it does not shear down to low-30 or even 20 in the heat as many oils do.
You're might be perfectly right in choosing M1 0w30 instead of GC for the winter. I guess I'm cheaping out, I bought M1 5w30 on sale recently, and that's what I'm going to use this winter.
I have very good UOA with GC from last winter; 10,000km. The oil saw some low temperature extremes, and turned out to be very good fit. I'll do UOA with M1 5w30 this time and then compare the two.

I am slightly worried about one vehicle I own- a 5 year old domestic minivan. During the weekdays it is driven 5 km to a Go Train Station in the early morning, sits all day, then 5 km back at night So most of the time it never gets up to a decent temperature. It probably accumulates about 500 km a month. Since mid Sept it has run GC. I will do an analysis of the oil sometime in January...just to see. 

[yugrus]

UOA will be a good indicator for oil change interval. That's some extreme vehicle usage; I'd personally stick to 3mo interval for the run before UOA. If it shows no fuel dilution or water and good TBN, I'd go longer. One month longer, that is... Take it on the highway for 30min once in a while, to burn off whatever does not belong there.

I'm questioning GC (or any other synthetic oil) usage as overkill here though. ANY oil would suffer a lot under these driving conditions, synthetic will not prevent fuel dilution (if any), nor will it perform better then dino while diluted. I'd rather go with 2 mo intervals on Pennzoil. That would be more cost effective then synthetic oil plus UOA. Deposits and sludge formation? I'm not sure you'll get that if you keep your interval short...