What's "short trip driving" these days?

[y_p_w]

I was looking at some messages attached to an automotive article, and someone was insisting that shutting down a warm engine and restarting it was a "dry start". Of course we know that's not true, with a nice coating of oil and almost instantaneous oil pressure when everything is already at operating temperature.

Still - what is short trip driving these days? A lot of manufacturers no longer consider city driving to put oil change intervals in a "severe" category, but "short trip" still is. My wife might take the Civic to drop off our kid at the grandparents or run a series of errands that combined, total maybe 12 miles with only warm starts in our mild climate. I'm sure that modern OLMs try to account for this, but not her Civic with the old fashioned "Maintenance Required" light every 5000 miles.

Even so - I get bored and have decided I'm going to change it every 5000 miles anyways.

 

[dparm]

I think most people here would say it's driving too short of a distance for the oil temp to stabilize.

 

[earlyre]

My commute.
approx 4.5 mi each way.
so, 4.5 mi to work, maybe 2 mi 4 hrs later on lunch, then 4.5mi home 4 hrs later.
def. 3 cold starts, without enough time for the engine to get fully to temp.
normally the water temp readout on my scanguageII hits 150 or so when i'm about a mile or so from my destination.

 

[Eddie]

I think some car manufactures say that anything less than 10 mile is considerd short. When I think about that statement, it really doesn't answer the question. Here in Fl. it takes about 1 mile for the water temp to stabilize and 2 miles for the oil. Based on that, I think maybe 2+5=7 miles is a good number for my vehicle. That is enough time for moisture to burn off. Ed

 

[jimbrewer]

Originally Posted By: Eddie
I think some car manufactures say that anything less than 10 mile is considerd short. When I think about that statement, it really doesn't answer the question. Here in Fl. it takes about 1 mile for the water temp to stabilize and 2 miles for the oil. Based on that, I think maybe 2+5=7 miles is a good number for my vehicle. That is enough time for moisture to burn off. Ed


Well, "start to burn off" anyway.

 

[Eddie]

Agree Jimb, but, once the oil reached burnoff temp and you shut the engine off, it doesn't go back to ambient in a few minutes.

 

[y_p_w]

Originally Posted By: Eddie
Agree Jimb, but, once the oil reached burnoff temp and you shut the engine off, it doesn't go back to ambient in a few minutes.

However, doesn't any evaporated moisture usually exit the crankcase via the PCV valve while the engine is running? If you're not running it, wouldn't moisture evaporating from the oil simply condense back into the crankcase once it cools?

 

[KrisZ]

Originally Posted By: y_p_w
Originally Posted By: Eddie
Agree Jimb, but, once the oil reached burnoff temp and you shut the engine off, it doesn't go back to ambient in a few minutes.

However, doesn't any evaporated moisture usually exit the crankcase via the PCV valve while the engine is running? If you're not running it, wouldn't moisture evaporating from the oil simply condense back into the crankcase once it cools?


Yup, it will do exactly that.

 

[CBR.worm]

I have the same question, and it is compounded by the fact that the vehicle in question has piston slap that does not go away in its short drives.

My older daughter changed schools this year, in the past it was a 20 mile round trip to drop off and then again to pick up, along with the other kid that was a
So now, the car has 8 trips a day that are <1.5 miles each - never warms up. On the weekend I still tow the trailer with it, but I am concerned that the 40 short trips during the week are bad for it, and wonder if it is worse due to the piston slap. On the plus side, gas spending will reduce a couple hundred dollars a month and the miles will rack up more slowly.

 

[KitaCam]

In my 4mi cold start runs I keep my MT in a lower gear (3rd rather than 4th) to keep RPMs higher encouraging a quicker rise in oil temps...