My take: dusty or dirty conditions - self explanatory. Driving while towing, using a cartop carrier or heavy loading - car pooling with 4 or more adults would fit this category. Repeated trips of less than 5 miles in temps below 32°F/0°C - specific enough. Extensive idling and/or low speed driving for a long distance such as police, taxi or
door-to-door delivery use - This would include commuter traffic if you get stuck in traffic that has you waiting to pass through traffic signals more than one cycle.
And under those conditions, I dare say a lot of people fall into the severe duty category And probably don’t realize it.
BustedKnuckles Extensive idling and/or low speed driving for a long distance such as police, taxi or door-to-door delivery use - This would include commuter traffic if you get stuck in traffic that has you waiting to pass through traffic signals more than one cycle.
But, again, what is it about lots of idling that’s tough on oil, I wonder?
Idling is engine operating time that is not recorded on the odometer. I have seen limousines and hotel/casino patrol vehicles with sludged engines from idling all day/night and not changing oil frequently enough, ignoring the time (months) requirement for maintenance.
When an engine is idling the oil is still accumulating operating time, gathering contaminants etc., but the odometer doesn’t move.
This is one reason that changing oil according to operating time would be more consistent than according to distance.
The repeated short trips in winter driving coincides with what I stated; moisture buildup in the oil.
The only caveat is that it’s applicable to periods of the year when it’s not freezing outside.
For every person who says they have no problems with 10k miles oil changes there are going to be far more who are complaining about their new or certified used car burning a quart per 500, 800 miles, or whatever and being told that it’s “normal”.
Moisture is one of, if not the, top reasons for lubrication related problems. From lawnmowers to cars to aircraft; it affects anything that uses motor oil. For those who chose to read it the following is interesting; especially from about the halfway point on down.
I remember CR did a test on oil change intervals a long time ago (70s or 80s). They took a bunch of NYC cabs and measured the engine wear. Then half got the oil changed every 3000 miles and the other half at 6000 miles. Engine wear was again measured and there was no difference between the 2 groups. The 6000 mile interval did not cause an increase in engine wear.
The problem with a test like that is it needs to be long term…not just ONE oil change.
Take 1000 identical vehicles in similar driving conditions…half using the 5k oil change interval…the other half with the 10k oil change interval…then record the problems and oil usage for the next 200k miles.
The things that’s bad about the CR cab test is that cabs get like one cold start a day.
I recall that all oils were excellent, with very few measurable differences. I understand why.
The CR test was done with 75 cabs for 22 months, over 4 million miles
That’s 4-million TOTAL miles…not 4-million per vehicle. Each vehicle was run to about 60k miles. While it’s a good test…to me it doesn’t go nearly far enough to be of any use. 150k is good…200k miles is better.
Duh! Did I say that?!? Who would interpret it that way?
The point is you’re trying to make it sound like this great useful test…and it’s not.60k miles is NOTHING. As I said in order for the test to really be useful the vehicles would have to go over 150k miles. Let’s see that test. I don’t know about you, but I keep my vehicles a lot longer then 60k miles…usually over 300k miles.
MNH, you are not considering how taxis are driven. Lots of short trips. Lots of stop and go traffic. Lots of idling. Lead foot drivers. That is tougher on the engine than your typical driver. So I’d say that is equivalent to your 150K.
I do not believe that extended idling is nearly as hard on oil as it used to be in the days of carbs. My van has spent the last four years idling extensively in the driveway during kid nap time. The rest of it’s usage profile is relatively short hops. The oil is always pristine looking at change time (~8k miles on the ODO).
BTW- the oil monitors all factor in idle time. Another good reason to use the built in reminder rather than your fixed mileage or time change schedule IMO.
The van is virtually sipping gas while idling. So although blowby is increased during idle, the amount of gas being injected is also far, far less. Especially compared to the days when this idea of extended idling was determined to be so bad for the oil and carbs were being used to meter the gas…
@sgtrock21 In England, where I visited recently and rented a car, the oil change interval was stated as 20,000 MILES! or one year, whichever came first for the Vauxhall (Opel) car I rented. These oils have a superior additive package, even better than the Mibil1 Long Drain interval types we buy here.
Europe is obsessed with minimizing waste oil and has pushed these drain intervals to what I believe are unsustainable lengths. You will find many Euro cars with at least a 20,000 kilometer drain interval specified. Since Europeans drive less, this will normally result in changing oil once a year for most drivers there.
I have been changing Dino oil and filter at 5000/6 month intervals since 1985. Since retiring I now do 6 months. Why? My last oil and filter change 8/28/2014 reaches 6 months the last day of this month. Miles driven as of today is 130 miles short of 2000. Unless something changes drastically I have no reason to monitor the odometer regarding oil change intervals.
