Long Drives to Offset Short Trip Use

Shel_B

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It's been said that, if you use your car for lots of short trips, it's wise to take it out for a long drive at some interval to heat up the oil and drive off the water, fuel, etc., that accumulates in the oil due to short tripping. I try to follow that advice and about every two weeks or so take a 50 mile or more drive to rid the oil of accumulated contaminants. But I've been wondering how effective the procedure really is.

If the car is taken on such cleansing drives only occasionally, then it seems that there's be a lot of junk in the oil most of the time, so how much good does the occasional long drive really do?

It also seems that the recommended time frame for such trips is arbitrary: once a week, a couple of times a month, once a month, every now and then are all recommendations I've read about. If these cleansing drives really have some benefit, might there not be a way to determine their frequency beyond some arbitrary number?
 
I do it on my Silverado, lot of short tripping in town, I like to go to a big mall with the wife next town over which is a 65 mile round trip. ;)
 
What do the additives in the oil do during the life of the oil?. And does the oil filter have a purpose on the engine?. The engine isn't a living thing, so worrying about how clean the insides are seems like a waste of effort. Most people don't own their cars until they fall apart, so use it as your servant until you move onto your next vehicle.,,,
 
One theory is that oil takes twice as long to come to temperature as does coolant. So, twice as long as it takes for the coolant to warm up is the point where the oil is warm and starts to lose its moisture that was accumulated during short trip driving. It'd be hard to give a concrete answer as far as how long to drive and how frequently to do it (not to mention the theory that it's completely unnecessary and a waste of gas which is probably true in terms of cost).

I think climate also plays into this in a big way - a car short-tripped in Fargo in January is going to develop a lot more contamination than an equivalent car driven on equivalent trips in Phoenix. To throw a wild guess out there, I'd say that a ballpark 25-30 miles past the point where the coolant warms up completely, done once a month or so, in more extreme seasons/climates would likely be helpful. Maybe just drive to a new coffee shop or ice cream stand in a town in the next county over or something on a Saturday morning, that kind of thing once in a while, if you never drive more than short trips around town. It's likely to be good (or, at worst, neutral) for the car and the change of scenery shouldn't hurt you, either.
 
It's been said that, if you use your car for lots of short trips, it's wise to take it out for a long drive at some interval to heat up the oil and drive off the water, fuel, etc., that accumulates in the oil due to short tripping. I try to follow that advice and about every two weeks or so take a 50 mile or more drive to rid the oil of accumulated contaminants. But I've been wondering how effective the procedure really is.

If the car is taken on such cleansing drives only occasionally, then it seems that there's be a lot of junk in the oil most of the time, so how much good does the occasional long drive really do?

It also seems that the recommended time frame for such trips is arbitrary: once a week, a couple of times a month, once a month, every now and then are all recommendations I've read about. If these cleansing drives really have some benefit, might there not be a way to determine their frequency beyond some arbitrary number?
It sounds like a good project for you. ;) Let us know what you find out!

One thing I do, since I live in a small town with a 3 mi trip to work, is take the highway bypass instead of the direct, but mostly residential roads. This increases my one-way commute from 3 miles to 5 miles and I get a 3 mile stretch at 60 MPH. It adds 1-2 minutes to my commute but who cares when it's still <10 minutes? That small change in enough to increase my annual miles from ~3500 to ~5500.
 
Maybe in the old carburetor days this was a thing, but I see no reason to do it with a modern car.
 
What is a short drive? Wife have a 15km ( 9.3 miles) drive to work one way. Almost whole drive is motorway doing 90km/h. Car is common rail with DPF. I'm not sure if the drive is too short longterm.
 
Making up for short trips is like trying to make up for lost sleep by sleeping longer the next night. I don’t think it works that way. The damage, if any, is done and will stay done.

A long trip certainly can evaporate water from oil if the oil gets hot enough for a long enough time. An oil temp of 212 for a couple of minutes isn’t going to evaporate squat.

My ’02 Jaguar XKR’s oil temperature is a constant 16-18 degrees F above the coolant temperature. Most of time the coolant temp hovers around 185-195. With a corresponding oil temp of 201 to 211. I’d really like it to get a little hotter.

There’s much more to blow-by gases than water vapor; ie the petroleum by products of combustion. Besides not evaporating, they accumulate over time and are heavily acidic. More damaging to engine wear surfaces than simple water vapor and the primary reason to change oil before a car sits for long periods of time if it’s used only seasonally.

Z
 
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I make several short trips to town per week. It is only 3-4 miles one way and downhill almost the entire way so that I can pretty much coast all the way. So what I do on the way home is put the car in the Sport mode and the transmission in the manual mode and make the return trip running the engine at higher RPM's. I figure that will get the oil temp up to where it should be.

I also make about a 70 mile round trip twice a month down to the closest large town, and drive back up the mountain in a spirited manner.
Not a very scientific test but all I can do other than using the best synthetic oil and changing it once a year or at 5000 mile intervals.
 
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