Excessive oil changes

[Charon]

Originally Posted by trollbait

But no manufacturer recommends a 3000 mile interval. 5000 is the shortest with many higher than that. It is just greed, ignorance, and inertia keeping people to the unneeded 3000 miles.

Not completely true. Perhaps no auto or truck maker recommends a 3000 mile interval, but motorcycle makers do.

My 2012 Tundra calls for 5000 miles oil change intervals, using full-synthetic 0W-20 oil. Apparently, some other Toyota models call for a 5000 mile oil FILTER change, with a 10,000 mile oil change. I used to have a 1964 Plymouth, which called for 4000 mile oil changes and filter changes every other oil change. The reversal is interesting.

[Jay2TheRescue]

I do 5,000 on my motorcycle. and IIRC, that's what the manufacturer recommends too.

[DPTyphoon]

Originally Posted by trollbait

But no manufacturer recommends a 3000 mile interval. 5000 is the shortest with many higher than that.

Took me awhile to find, but the Owner's Manual for my 99 Ford Diesel does indeed want 3,000 mile change interval IF the service is deemed "severe". The "normal" interval is 5,000 miles. Because my usage involves towing a 6,000lb box trailer about 75% of the time, my usage fits "severe".

Here's a copy/paste from the Owners Manual:

Engine lubrication for severe service operation
The following severe service operating conditions require unique engine
maintenance procedures:
² towing a trailer over 1 600 km (1 000 miles)
² sustained, high speed driving at Gross Vehicle Weight Rating
(maximum loaded weight for vehicle operation during hot
weather-above 32°C [90°F]).
² frequent or extended idling (over 10 minutes per hour of normal
driving).
² operating in severe dust conditions.
² frequent, short trips of 16 km (10 miles) or less during freezing
weather
If you are operating your vehicle under any of these conditions, observe
the following service procedures:
² Change engine oil and filter every 5 000 km (3 000 miles).

The Powerstroke Diesel has special consideration for oil change interval because of the HEUI injection system that uses high-pressure engine oil to fire the injectors. These considerations take into account conditions that deplete certain additives such as anti-foam ingredients that can affect injector operation.

I've been conducting oil-analysis to determine my optimum interval. I've had 5,000, 7,500 and 10,500 mile oil analyzed. Based on TBN estimates, I've settled on a minimum 9,000 miles, not to exceed 12,500 or two year interval. Many of my trips are 3-4,000 miles in a week or so. That's why the range. If the oil has 11,000 on it, and I'm going on a 3,000 trip, change before leaving. If it only has 9,500 on it, do the trip and change upon return.

The last interval of 10,500 miles was only 4 months. The engine ran noticeably smoother with fresh oil. Ford may really know what they're talking about stipulating the short intervals. But it holds 14 QUARTS of oil. 3-1/2 GALLONS. Even with DIY, my oil changes are $125. That's 4 cents per mile for OIL. I may be over-doing the interval, but I won't spend that kind of money for oil changes. There's guys on here that spend less than 4c per mile for FUEL!

[Draigflag]

I've only had 10 cars, I think the smallest interval for oil was 9000 miles, and that was a high revving turbocharged high stress engine. The average has been around 12,000 miles, but that was on cars over 10 years old. Engine technology and oil development means these higher 20,000 mile intervals are perfectly safe and normal and its time the US started using the same quality oils so they can do the same.

[JanGeo]

2006 Scion xB first oil change 3800 miles March? 2006 running Synlube ... Did a couple of filter changes since then and added maybe a quart .... Now at 68500 miles and time for a change but I send the old Synlube back for recycling and get money back for every ounce. Typically I average over 40 mpg which makes it practical since the gas tank is only 11.9 gallons and getting that last gallon in takes about 5 minutes of clicks!

[trollbait]

I've never even sat on a motorcycle, so didn't consider them in my statement. With most being designed for high performance, with smaller oil capacities, I can see why they might need a shorter oil change interval. Doesn't their oil have different standards than car oil? They also aren't a daily driver in many cases, and even if, weather and other considerations means they won't see the annual miles of a car.

I've heard of some cars only recommending changing the oil filter every other oil change. I don't see the logic for it though. Aside from fitting the engine with larger or multiple filters, the oil filter will be mostly clogged with the bypass valve open before it is time to change the oil. I don't remember why, but I did change the filter once about half way through the interval. After a week, the black oil was almost back to the color when fresh, and mostly clear.

I have considered doing more frequent oil filter changes, and cartridge filters almost make that a non-chore. It's just that being black isn't really a bad thing for the oil. It means the detergents are doing their job of keeping dirt and gunk in suspension and not depositing.

I think the severe service listing is mostly for CYA, and to give the manufacturer a weasel out of warranty work for something extreme. Taxi service falls under the severe listing in the manual, but it has been reported that NYC cabs, mostly Crown Vics, go 6000 miles between changes. It doesn't fall under the topic of oil changes, but I don't Toyota recommends any of their hybrids for taxi work. Yet I haven't heard of any major reliablity problems in the thousands already doing that job.

If the oil is also being used for something beyond lubrication, that does change things. Automatic transmission fluid is more delicate than motor oil because it also has to be an hydraulic fluid.

The engine ran noticeably smoother with fresh oil. Ford may really know what they're talking about stipulating the short intervals.

I wonder if just changing the oil filter is enough in that case.

[DPTyphoon]

Originally Posted by trollbait

I wonder if just changing the oil filter is enough in that case.

There is an indicator in the oil analysis that helps with assessing filter life and change interval. Called Insoluble, and the max value is .07%. My 10,500 sample was .02%. If this number is high, the filter is saturated, the bypass is open, and particles aren't being filtered out. The filter interval was too long.

In the Powerstroke, I think the anti foam and other characteristics of the oil affect the way the injectors are fired. Engine oil is pressurized to 450-3,000psi by an axillary High Pressure Oil Pump to provide the energy to pressurize the fuel for injection.

Running engine oil at 3,000psi has to do something to it that a normal car engine doesn't. And influences the manufacturer's change interval recommendation.

This is a good article I found this morning on the HEUI Injection operation. Thanks for the interest.

[Draigflag]

Did I read that right? Your truck holds 3.5 gallons of oil? (almost the same size as the fuel tank on one of my past cars!) So if you were to change every 3k like some people do, your car would use about 440 litres of oil per 100,000 miles. My car would use just over 16. That's 440 V's 16, I hope now people can see my concern, and why I started this thread, were not talking about fractional differences here now are we!

[trollbait]

It's a 6+ or even 7+ liter engine that came out before we had ULSD. Before they went to liquid cooling, a Porsche held over 2 gallons of oil. It provided cooling in that case, and may do so for these big diesels.

The oil capacity is still that much, but Ford has moved onto an oil life monitor system. The change interval can be as low as 3000 miles under extreme conditions. I expect most people are in the 7500 to 10k mile range.
http://www.fordservicecontent.com/Fo...US_02_2014.pdf

Came across a post once by somebody that had one of those aftermarket bypass oil filters. He plumbed up to a pump and tank, and ran the old oil from the DDs through it until clean. It was tested to make sure the additives weren't completely exhausted, and then used it in his truck.

Back to the '99 Ford diesel. If there was a way of filtering it, adding the 3.5 gallons of old oil to a full tank of diesel wasn't unheard of.

[Jay2TheRescue]

You have to consider though that the Ford Powerstroke engines are large, heavy duty turbo diesel truck motors. 7 to 8 liters displacement if I remember correctly. These are not put in cars. They're put in trucks and vans, 3/4 ton & up.