Moisture in the Crankcase

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How long does it take for moisture to burn off at operating temperature? If you drive 5 miles and oil temp is at operating temperature will all the moisture evaporate?

This is for a car that is being driven very little to keep miles low.
 
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What's the outside temperature? 70F warms up quick-below zero, not so much... Different vehicles warm differently too, the xB in my sig has exceeded 140F coolant temperature in less than a mile, but some of the diesels I've driven needed a winter front to ever warm up below zero.
 
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So if the water evaporates, how do we know it actually leaves the engine as opposed to hangs out somewhere inside then returns to the oil as a liquid again?

Are we assuming it's being sucked up through the pcv?
 
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my elderly aunt had that issue due to little driving + short trips, simply change the oil more often + you can prolly use cheaper oils that are not for longer drains. with todays inflated gas prices this may be cheaper if you DIY oil changes + of course as recommended a longer drive!!
 
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Previous discussions on this topic wrapped up stating a 30-minute highway run every 2 weeks *should* be enough to burn off all moisture accumulated in the crankcase. But of course it depends how much moisture we are talking about, which is hard to say. If normal usage continues to be short trips, this is considered severe service and I would use the cheapest oil that meets the spec and change it every 6 months or so.
If you're trying to keep miles low and worried about crankcase moisture buildup, maybe use the car once a month when a longer trip is needed? As compared to several short trips every month. Just a thought.
 

HondOtaChOrd

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I think sitting for a month is not good for all the seals, gaskets and everything else. That's why I go for every other week max as a general rule.

What do most think about once a month driving?
 
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I think sitting for a month is not good for all the seals, gaskets and everything else. That's why I go for every other week max as a general rule.

What do most think about once a month driving?
I don't know. I have a vehicle that sits sometimes for months. If you're in the "cold starts cause wear" camp then an unnecessary cold start may not be something you are a fan of.

Do seals become brittle? I don't know. It's got high mileage oil in it. I've had this vehicle for about 4 years now and knock on wood it's developed no leaks from its infrequent drives.
 
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I'm retired now but when I did a short commute on my bike right through the winter, condensation and mayonnaise production was a potential problem. More miles wouldn't have been the complete answer as being air cooled it was grossly overcooled in the winter and the oil just wouldn't get up to temperature. What I did on arriving home and parking up in the garage, was remove the dipstick and let the crankcase breath overnight. It worked, if there were traces of mayonnaise around the dip stick hole it would be gone by morning as the residual heat in the oil drove off the moisture. If I didn't let it breath then there would be considerable build up of mayonnaise.

Not so easy to do with a car and it would have to be garaged but I'm sure it would work if you removed the oil filler cap every night.
 

HondOtaChOrd

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I have a car that will be sitting for a month due to weather. If this car is started any longer than 3 weeks it doesn't start as happy as usual. Possibly the fuel lines are not full. It cranks longer. If it sits 2 weeks not an issue. Also left on a battery maintainer while it sits.

My question is how bad would it be to start it after 2 weeks and just let it idle. Yes there will be moisture build up although 1 to 2 weeks later I can take it for a proper drive. OCI is once a year.
 
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How long does it take for moisture to burn off at operating temperature? If you drive 5 miles and oil temp is at operating temperature will all the moisture evaporate?

This is for a car that is being driven very little to keep miles low.

Oil will not come up to temperature in 5 miles. 2 of our cars have oil temperature gauges one takes around 20 minutes the second takes about 10 but that car is a 4 cylinder turbo
 

HondOtaChOrd

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Yes, I know oil will not get up to temp.

That is why I am asking how bad is it for oil to sit for a week with moisture. The following week I can take it for a long drive to get up to operating temp and burn that moisture.
 
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After mention here of the steam after the oil cap is removed, took notice of my Kia 3.5, it had a brown froth on the underside of the oil cap too. Also recall how clean the front bank was under the valve cover. Many short trips as this is the assigned winter duty vehicle. My solution was too add idle time whenever I can and to do the oil change in the spring.
 
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