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homeless · 07-31-2015, 09:36 AM

I have a Ford V10, I have a battery disconnect and a battery booster so I don't have any thought about not having battery to start motor after a couple of months.

My question is, is it good to start the engine and let it idle occasionally or is it better to just leave it shout down?

Skip426 · 07-31-2015, 09:53 AM

JMHO: If you can't drive the unit and run it long enough to get it up to full operating temperature, best to leave it sit.
Idling after start up will introduce water vapor, and un-burnt fuel into the oil; produced during start up, before the pistons and rings expand and seal properly; and if you don't run long enough, hot enough, to have the engine systems ( PCV valve) remove those , then they accumulate in the engine and produce sludge and rust.

wa8yxm · 07-31-2015, 09:55 AM

If you start the engine you need to get it up to normal running temp under load for at least a half hour to do good.. Just letting it idle is generally considered a bad idea. though not as bad as it was 50 years ago if it is a computer controlled gas engine.. Worse than it used to be if it's a Diesel.

homeless · 07-31-2015, 09:57 AM

Thank you for bolstering my thought on the subject.

Happyho · 07-31-2015, 09:57 AM

I have to agree 100% with Skip426. I think the starting up and running came from the days when you had to keep your oil seals soaked in oil by running engine.

Dtwallace · 07-31-2015, 09:59 AM

If you are not going to drive the vehicle long enough to bring it up to normal operating temperature for at least an hour, it's best to not start it at all.

The reason is moisture from the combustion process creates water. some of that water ends up in your crankcase and will mix with the engine oil. the mixing of water and oil then creates acid in the your oil that attacks the metal bearings and other parts of the engine crankcase ventilation system.

Water and acid is also created by this process in your exhaust system. This in turn will rot your exhaust system out early.

Driving at highway speeds or long (an hour or more) trips at street speed driving will heat the oil and the complete engine system enough to dissipate most of the water though the crankcase ventilation system and out of the engine drying it of water.

This means your oil change intervals are of the normal times, where as if you would just occasionally start the engine, your oil would need to be changed more frequently to get rid of the acid in the oil system.

Bottom line, no do not just start and idle your engine to exercise it bad for the engine.