How long do you go between oil changes?

[Hematite]

OT:

Hematite--how's that MF 2925 holding up for you? The guy that delivered my 2823 had 1 of the 2900 series MFs and spoke very highly of it. There aren't too many of us on TBN with a MF mower.

Back on topic--I stick with the severe svc. schedule in the manual on my truck just because I meet several of the criteria for severe svc. About the only people who meet the "normal" svc. standards are those who put on nearly all of their miles cruising on the hwy unloaded. Stop and go, dusty conditions, short trips, towing/hauling, are all considered severe, and most people will meet at least a couple of those conditions.

Baucom,

That MF 2925 is completely awesome! Mine is a 2003 which was the last of the 2 wheel drive only models. They were built by Simplicity for Massey. I did a bunch of research before I bought and the components used are simply the best available for the size range. The mower cut is unmatched by any other and the snowblower is so powerful that people stop on the street in awe at the distance that it blows snow. I only have about 200 hours on the Kohler 25hp air cooled (I wanted to keep it simple) and the machine still functions like new. I'm a die hard fan of this Simplicity Legacy variant!

 

[Redneck in training]

I am working on large compressor and turbines. All machines have a start permissive interlock based on low oil temperature. The oil temperature has to be 30C/86F and higher for synthetic and 25C/77F and up for mineral oil. If the oil is colder and more viscous the bearing shear force breaks down (shreds) the large oil molecule chains to shorter and the oil will loose its lubricity.
If this also applies to car engines most of oils damage would happen during cold starts then.
Somebody mentioned NY cabs oil test. Years ago I heard about similar story also about NY cabs or NYPD. They selected two groups of brand new Chevy Impalas. One group changed oil every 3000 miles and the other changed only filter and add oil. The engines were taken apart at 200 000 and supposedly there was not difference. Is it true or another urban legend?

 

[Bird]

I don't know whether the story about the New York cabs and NYPD cars was true or not, but I wouldn't be surprised. I know that Ford used to do a lot of their experimenting and testing on Dallas Police sedans. We used to nearly all carry revolvers and when you turn to get out of a car, it was common for the cocking thumb to hit the steering wheel, and pretty soon the steering wheel has lots of chips, gouges, etc. I remember in 1964, we had lots of different colored steering wheels; the cars were all black, but some steering wheels were black, some white, some red, some blue, supposedly testing different compounds. And when you raised the hood on one, it might have a white distributor cap instead of black, or there might be a section on top of the radiator painted white with some numbers on it, and such things as that. And in 1968, first year for air-conditioning, one of the cars had such a trunk full of car batteries that it appeared the back end of the car should have sagged. There was a sealed metal box in there also that the batteries were hooked up to. I don't know what kind of data it was recording, and I never drove that particular car myself, but the guys who did, said it had more power and acceleration than the others, even though the engine looked the same.

One rumor I heard, never confirmed, but wouldn't doubt was that the reason Ford was the first to produce manual 3-speed on the column transmissions with low (first gear) synchronized was that the Dallas Police tore the transmissions out of so many cars that Ford developed the synchronized low just for that reason.

And in those days, the marked cars ran 24 hours a day six and two-thirds days a week. Each car went in one shift a week for oil change, grease, and wash, whether it needed it or not. In later years, they started having an oil analysis done, and of course, now I have no idea what they're doing.

So, yep, the manufacturers, parts suppliers, etc. do (or at least did) a lot of testing on fleet operations so I wouldn't doubt the story about the New York cabs.

 

[California]

The NY cabs urban legend probably refers to Consumer Reports' tests in 1996. Their goal was to see if synthetic oil made any difference, and they found no difference.

From Wikipedia:

In July 1996, Consumer Reports published the results of a two year motor oil test involving a fleet of 75 New York taxi cabs and found no noticeable advantage of synthetic oil over regular oil.[12] In their article, they noted that "Big-city cabs don't see many cold start-ups or long periods of high speed driving in extreme heat. But our test results relate to the most common type of severe service stop-and-go city driving." According to their study, synthetic oil is "worth considering for extreme driving conditions: high ambient temperatures and high engine load, or very cold temperatures." [13] This research was criticized by some because most engine damage appears to be caused by cold starts, and their research method may not have included enough cold starts to be representative of personal vehicle use.[14]

But Google on consumer reports oil test cabs. That brought up AmsOil and other's criticisms of CU's test methods.

I remember reading CU's article at the time. As I recall, they had no oil related failures, but a couple of engines failed during the test by dropping a valve or something like that.

 

[LBrown59]

100 hours.

 

[crashz]

I don't know about you guys, but I've been changing oil in my own vehicles for nearly 20 years and have been so entrenched in the old ways that its still hard for me to go much past 5000 mile changes.

In the same respect, I just spent about $85 dollars on oil and filters for my pick-up and my soon-to-be-wife's car and cannot remember when I paid more for regular oil. Even the lesser brand names or no-name brands are $3/quart. Oil is no longer "cheap" insurance.