>> >>
>>>>>>> >>>>
>>>>>>>>>>>> I'm a regular guy (retired) with 4 vehicles that always have, and always
>>>>>>> will, get 3k oil changes on straight 30 weight oil.
>>>>>
>>>>>> This will increase the engine wear at start-up, though if you're in a
>>>>>> hot climate it won't be too bad. Just make sure that it's a detergent
>>>>>> SAE 30, not non-detergent, as both are available.
>>>>>
>>>>>There are some engines with small oil passages where it's probably not a
>>>>>good idea at all.
>>>
>>>> Not an engine built that can't run straight 30 if the temps don't drop
>>>> below something like 55-60F.
>
>>>Funny how the same people who demand that 3,000 mile oil changes are
>>>needed just to prevent engine damage feel that changing oil weight from
>>>recommended is just fine and dandy. Afterall, the engine was extensively
>>>tested by the manufacturer with the weight of oil specified.... and you
>>>just 'know' what will work 'better' in it without so much as engineering
>>>drawings of it.
>>>
>>>I'll stick with the recommended weight oil, as I know there are small
>>>passages in it and I'd rather be sure everything got oil.
>
>> I've been a mechanic since the sixties, and have rebuilt untold >> numbers of engines.
>
>That's nice.
>
>> I've never seen oil passages that can't flow
>> adequate oil of a reasonable viscosity for the temperatures involved. >
>Not going to risk sludging them up using straight 30 weight oil because
>some 'mechanic' on usenet said so. I'll use the lubrication that the
>manufacturer says is acceptable. I don't have the money to do engineering
>experiments with my cars that involve destroying engines.
>
>> And I know enough about oils to know what is safe.
>> If you know how to read the manuals, most show a range of oil
>> viscosities acceptable for a range of temperatures (or did up until a
>> few years ago). In areas where temperatures do not change much, single
>> weight oils CAN be acceptable and effective under certain conditions. >
>Too bad you can't read what I wrote. If the manual says to use straight
>30W go for it, but that's not the case here.
Too bad YOU cant read. What part of "I don't recommend them" do you not understand??????
>> I don't recommend them. But I DO recommend, in many cases, oil a bit
>> heavier than the manufacturer recommends. And I reccomend wider
>> viscosity ranges than some manufacturers recommend.
>
>Because you've done all the tribology experiments and accelerated life
>testing to back it up right? All on your own and on your dime. Maybe I
>should drop the engineering gig and become a mechanic if mechanics have
>that kind of money to piss away doing expensive experiments and reliability
>testing like that.
Actually, I HAVE had the data to back it up. When I was Toyota service manager Toyota was recommending 5W30 oil year round. They were replacing the odd camshaft. They were replacing timing chains. They were having problems with timing chain tensioners and guides. I was in conversation MANY times with the engineers, and they said they "could not recommend 10W40 and 20W50 oils for use in their vehicles because it would contravene the laws in place regarding C.A.F.E." I was free to recommend whatever I wanted to recommend to my customers as long as I did not intimate that Toyota suggested it. They said there was no engineering reason why 10W40 and 20W50 oils could not be used if they were changed often enough to avoid viscosity breakdown. And guess what? NONE of my customers EVER had a camshaft or timing chain or tensioner problem that required the engine be dissassembled or repaired. NOT ONE. I did replace a fair number of camshafts, timing chains, and tensioners in vehicles that had been serviced by other dealers, following the factory recommendations. Any question as to why my retention rate was the highest in eastern Canada? On a 3 year weighted basis, I was servicing more cars than the dealership had sold. That's seeing the car more than twice a year for service when the car was 3 years old or older.(long off warranty)
>> A 10W40 oil is
>> totally acceptable in place of a 10W30 IF IT IS CHANGED OFTEN ENOUGH. >
>Because a mechanic says so....
>
>> And 10W40 has the advantage that it holds viscosity better under high
>> operating temperatures. Although more wear MAY be caused by cold
>> starts, more serious damage is caused faster by lack of lubrication at
>> high temperatures and high speeds and loads. Catastrophic failures
>> seldom accur at startup on a cold engine.
>
>Because you looked a couple tables and graphs and it 'feels' right, or
>did you actually run experiments, accelerated life testing, and field
>testing on a wide variety of engines in a wide variety of vehicles? It
>would probably only cost several hundred grand to do, those bogus
>transmission flushes must really bring in the cash.
Accelerated life testing was done by several customers who used tercels for delivery service, racking up opver 500,000 in 2 years. And by others running Hilux pickups for courier service, with about the same mileage accumulation. And customers who commuted 160 miles a day with Supras, and kept them for 5 years. And for your information, I never did a BOGUS transmission flush. Did I do transmission flushes? Yes I did - and I NEVER had an automatic transmission failure on any of my customer's vehicles. NOT ONE. (and no specialized megabuck equipment to do the flush either) The transmission flushes I did were not "cash cows" - straight time and material. (I was in charge of what was likely the ONLY non-flat rate dealership repair shop in eastern Canada at the time.) I changed the transmission fluid at the manufacturer's specified intervals, and flushed to replace ALL of the fluid, not just part of it. I had over 600 vehicles under my "exclusive" care, as well as several hundred more that came to me for some of their service, and went elsewhere, or did it themselves, for the rest.
>> That said, you are likely best to follow the manufacturer's
>> specifications TO THE LETTER, as you obviously don't know enough about
>> engines or oils to make any educated descision to do otherwise. >
>Yeah... two mechanical engineering degrees
That says a lot.
and a decade working in
>product design
And what products? I've done product development too.
and development and I know nothing about lubrication or
>engines or anything regarding the testing that's done by the manufacturer
>to come up with what is recommended.... I know nothing about how
>products have odd little failures in testing but slight tweaks
>prevent them.... slight tweaks like what lubricant to use. I know nothing at
>all. I should put all my trust in some guy on usenet who claims to have
>started as a mechanic in the 1960s.......
No, as I said YOU should follow the manufacturer's recommendations to the letter. YOU trust the manufacturer to always do what is best for you.
I'll go by my experience, and my training and knowledge. Those who know me and trust me will take my advice. They have for decades. I'm not expecting you to.
just put that 10W40 where the
>manufacturer didn't recommend it because he says so.... So what if maybe
>the manufacturer of my engine tested it with 10W40 and had failures in
>testing so that's why it's not on recommended.
Well, I know most manufacturers did NOT test with 10W40 and have failures that were prevented by using 5W20.
The ONLY reason 5W20 oil saw wide adaptation in the North American automotive market was for fuel economy reasons. The critical clearances in today's engines are virtually the same as they were 35 years ago. Precision and finish are perhaps better today than then,allowing nominal clearances to be SLIGHTLY closer than they were because MINIMUM clearances have remained the same. (less "peaks and valleys")
... This mechanic on usenet
>must have access to all these internal automaker test reports and spends
>countless sleepless nights reading them all, he knows the best oil isn't
>one on the chart....
>