0W20 oil

It's close. Long chain polymer VI improvers coil up and thicken the oil somewhat when hot. (not thicher than when cold, but thicher than they would be without them) If and when these long-chain polymers shear, they loose their ability to stabilize the viscosity.

This is about half of how multigrade oils work. At the other end, pour point depressants keep the oil from thickening as much when cold, and friction modifiers reduce the cold strat friction, reducing the cranking power required to start the cold engine (which is part of the SAE test sequence for the XW part of the rating - so in reality a

10W30 oil is closer to a 15 weight oil with addatives - or even a 20, in the "real world"
Reply to
clare
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Tell the poor sucker in Moose Jaw Sak or Billings Montana that when he tries to start his car New Years Eve with 30 weight oil in it.

Or even in London Ontario, Detroit Michigan, or Oshkosh Wisconsin.

Now the 0W20 and 5W50??? Yup - fuel mileage ratings. Pure and simple.

Reply to
clare

But not true if the vehicle was always in Pheonix Arizona, Ougadougu Berkina Faso, Livingstone Zambia or the UAE. Or at least 10,000 other places I could name where 65 degrees F is a COLD day.

In those places, running a 50 weight oil would cause ABSOLUTELY no problems. (Been there, Done that. Wore out the T shirt)

Reply to
clare

At -40, a 20W weight oil is thick like tar and starting is VERY difficult. A 1969 Dodge slant six would not turn over - after an hour with heat, it finally started and blew the oil filter off. With a 10W base oil (10W40, in fact) it started perfectly the next morning, at -42F

I'd have hated to even think about #30 without a block heater - Which I'm sure you used on the 400 Ford.

Reply to
clare

There is a world, or two, of difference between a 53 flathead V-8 and a modern engine.

Reply to
salty

Incorrect. Flat out, incorrect.

Reply to
salty

How am I incorrect? Prove it to me. And what are your qualifications to dissagree? Why should I believe you? Come on, convince me. I'm a licenced mechanic for 36 years, and an instructor at both secondary and post-secondary (trade) level.

Show me yours.

Reply to
clare

rolls eyes

Reply to
salty

no block heater. if the engine is in proper tune, it makes absolutely no difference what weight oil is laying in the oil pan. Also ran a 6.9 diesel (85) on straight 30 after ford recommended it. No problems starting it either to go out snow plowing.

s
Reply to
Steve Barker

Your experience flies in the face of decades of experience up here in the great white north.

Reply to
clare

Well the very worst we see as a rule is about 10 below actual temp. Very, very rare to be colder than that. And mostly between 0 and 20 most winter nights. (kansas city area)

Reply to
Steve Barker

Don't assume that the dealer automatically uses the recommended oil.

I had an oil change on my 4Runner at the dealer. The manual recommends

5W30, they used 10W30 because it's what they have in their bulk oil tank. I had them change it to 5W30 which they had only in bottles.

By now they probably switched their bulk oil to 5W30.

My relative has an auto repair shop in San Francisco. When 5W20 first came out it was for Hondas, and he could not buy it from his oil supplier, only from Honda. The Honda parts person told him that the Honda dealer just used 5W30 on the vehicles that specified 5W20 because the 5W20 was much more expensive. But an independent shop needs to be more careful than the dealer for liability reasons, and not use the wrong oil. Now he has 5W30 in his bulk tank, and uses bottled 5W20 which is available from many oil jobbers.

Reply to
SMS

Actually multi-viscosity has nothing to do with gas mileage, it has to do with excessive engine wear at start-up. At operating temperature the

5W30 and the 30 have the same viscosity.

In tropical climates you're probably fine with straight 30 in a vehicle that specifies 5W30, you'll get slightly more engine wear at start-up but not enough to worry about.

Reply to
SMS

Sure, if the ambient temps where you live are the same as normal engine operating temps. Then it would be no problem.

Reply to
salty

You have a lot to learn about oil!

Reply to
SMS

not really. I've been using straight 30 in EVERY thing i own since i started driving in '73. Been an ASE certified master auto and truck mechanic since '79 and have never had ANY kind of major component failure in an engine i owned EVER. And they never get driven less than about 180 - 200k miles before i get rid of them . And with the exception of the 400 ford i mentioned before that was worn out when i got it, I've never had oil consumption issues with any vehicle either. Oil is oil as long as it is kept changed regularly. Period.

s
Reply to
Steve Barker

Thing is, 5W30 is safe to use in any engine that specifies 5W20. The company cannot recommend it because they MUST recommend the oil used to qualify the car for CAFE under American law. The only difference between using 5W20 and 5w30 is about 2/10 mpg fuel economy (at best)

Reply to
clare

Doesn't have aproeach engine operating temp at ambient to be OK. The flow rate of straigt 30 at 45F is better than the flow rate of

5W20 at 0F - by a significant margin.
Reply to
clare

I swear this is true. I knew a guy who had bought a new kawasaki moped for his wife (I think in the 1980's). When ever he needed 2 stroke oil he would only buy it at the Kawasaki dealer. He did this for years. Then one day he went to the dealer for something else (I forget what?) and he wasn't treated like a king. He told whoever he was talking to that he is a loyal customer and always buys the 2 stroke oil there!!!! They still couldn't help him with whatever his problem was and he badmouthed them ever since. And he actually still tells people that he always bought the 2 cycle oil at the dealer because of course Kawasaki oil would be the best choice for a Kawasaki motor!

When it came time to buy a computer for his daughter he decided that since IBM was so big in computers from the early days, that the best possible PC would be an IBM, and price didn't matter if he was buying the best. So he paid out the ass for an IBM and every possible accessory that had the IBM name on it.

Reply to
Tony

I just now remembered something I saw on a cool morning in the pits at what was "Indy" races. Almost everyone had a torpedo type kerosene heater blowing on the rear differential long before the race started.

Reply to
Tony

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