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I’m having an issue with idling. Two years ago Car Talk answered someone’s question that it was okay to keep idling all night to keep the heat on if sleeping outside during winter. He was asking if it caused engine damage and they said no. What is the final verdict? Is it okay to let an engine idle for extended periods? Does it make sense that an engine would get more worn by idling than driving?

engine oil pressure is at its lowest (aside from when the engine is not running of course) when idling. But the stress on the engine is also at the minimum. It burns fuel all the time its running, but other than that I dont see a problem. Of course if a fan belt breaks or there is a cooling system failure and the engine is running with no one attending it that could fry your engine. Why anyone would want to do this, let an engine idle all night I dont know. Dont sleep in the vehicle if you do this though, because of carbon monoxide poisoning danger. and make sure there is no danger of the shifter getting moved into gear (no open window for a dog to jump in). I have to say this seems like a weird question to me.

Do you plan on getting stranded or using an idling car for other purposes ? Yes it does add some wear to a car, but so doesn’t driving them. Taxi cabs and police do all the time, all night long for hours at a time, so they can certainly take it for the occasional “getting stranded” situation, whatever that means.

piston ring blow-by and fuel/oil dilution issues. any comments?

If this is a fairly modern car, the engine will be running in closed loop at idle so the mixture will stiociometric referenced to the O2 sensor. The cylinder blowby will be minimal and handled by the PCV system which is operating at high vacuum. Also on most transverse mounted engines the radiator fan is electrical and will cycle as the engine coolant reaches higher temperature.

With respect to wear, the engine is under light load; the oil is warm; and flowing so there probably will be less wear per hour than one cold start.

You bought a car so it can meet your needs. If being in an idling car for extended periods is something your need the car for, then do it and don’t even worry about it. You will never notice any difference with engine life.

The worst and riskiest part of it, as others have said, it don’t sleep in the idling car. The risk of CO poisoning is very real.