Been following the 0W/20 etc. saga...

[dailydriver]

Originally Posted By: CMMeadAM
+1 !!!!

Since 2002, we have enjoyed the problem free performance
of 8 Toyota/Lexus vehicles. Absolutely NO problems whatsoever, especially NO engine problems. We fully realize ours is a small sampling of the total out there, but the overall PROBLEM FREE performance of these vehicles has been the
best of the many makes we have owned.


Good for you!

I have had the same experiences with domestic manufacturers other than the Nippon Giant, so I guess this said 'perfection' is NOT exclusive to just them, huh?
(And mine are MUCH more fun to drive, as well as faster than their 'refrigerator on wheels' lineup.

)

 

[45ACP]

Originally Posted By: lexus114
Originally Posted By: CATERHAM
You're right but everyone knows using a 20wt oil, especially a 0W-20 can cause all kinds of problems, everything from male pattern baldness to impotence and that's why real men will never use 20wt oil.




Wow, it does all of that huh?


Not only that, it does it in your engine.

 

[bullwinkle]

Originally Posted By: dailydriver
Originally Posted By: CMMeadAM
+1 !!!!

Since 2002, we have enjoyed the problem free performance
of 8 Toyota/Lexus vehicles. Absolutely NO problems whatsoever, especially NO engine problems. We fully realize ours is a small sampling of the total out there, but the overall PROBLEM FREE performance of these vehicles has been the
best of the many makes we have owned.


Good for you!

I have had the same experiences with domestic manufacturers other than the Nippon Giant, so I guess this said 'perfection' is NOT exclusive to just them, huh?
(And mine are MUCH more fun to drive, as well as faster than their 'refrigerator on wheels' lineup.

)
Hey-my wife's xB resents (resembles?) that 'fridge on wheels' comment! And to think we wouldn't have it if we wouldn't have had a GM product ('03 Vibe) BOUGHT BACK AS A LEMON!

 

[hominid7]

Originally Posted By: Garak


I'm not exactly positive; others know a lot more about that than I do. If you check Ford's list, it seemed that certain engines (at least in certain applications) were excluded from the 5w-20 back spec, notably the 302 and the 4.0 L V6, from my quick skimming of the document. I'm sure the 300 straight six wasn't back speced either.


I found the list online and verified mine didn't make the 5w20 approved list. That's too bad, i'd really like to use it, but if Ford/Mazda doesn't think it a good idea, then it likely isn't

 

[440Magnum]

Originally Posted By: hominid7
Originally Posted By: Garak
From what I understand, it was the oil pump.


That's what i was thinking it had to be. It would be interesting to know what differences viscosity made with older pumps...


Its all about the how many cubic inches of oil the pump moves per rotation of the crankshaft. Engines spec'd for Xw20 oils usually have a higher-volume oil pump. The thin oil "escapes" out the bearing clearances, timing chain sprayers, piston squirters (if equipped) etc. at a higher rate than thicker oil, so an HV pump is needed to maintain oil pressure, especially at hot idle.

As a side note, I installed HV pumps when re-working both of my 60s vintage 440s years ago, and I'm quite sure they could both maintain factory-specified oil pressure on an Xw20 oil. And I might even try it... EXCEPT for the flat cams than need more anti-wear additives than Xw20 oils have. I'd planned to run 5w30 when I built the last one, but that was when SJ oils were still the latest and greatest. An Xw20 HDEO might work just fine in them, but in reality they get M1 0w40. If I'd known in 2001 what I know now, I'd have planned those engines for Xw40 oil from the get-go and just put standard volume oil pumps in them. I may even switch them back the next time I'm working around the driver's side motor mount- one great thing about Mopar big-blocks: externally-mounted oil pump. No pan drop required!

 

[hominid7]

Thanks for the explanation 440Magnum. This winter i might experiment with a few high mileage oils in 5w30 and see how they act.