Ok to Idle the 392?

B92

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22 JT Mojave, 23 JL 392
Quick question. When I don’t use the 392 during the week, ok to run it or let it idle in the garage for a few to keep the battery charged? Thank you.
 
I would throw a charger on it every other week. You don’t get much out of your alternator at idle.
Ok makes sense. Thank you.
 
Quick question. When I don’t use the 392 during the week, ok to run it or let it idle in the garage for a few to keep the battery charged? Thank you.
How long does your Jeep sit on average? Mine "might" get driven twice a week on average but usually only once a week. We have never owned three vehicles at once and never realized how little we actually drive until now. When I or we decide to go somewhere we often choose the vehicle that hasn't been driven the longest. Sounds like I need to invest in some "more" smart trickle chargers.
 
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More than your battery is of concern. You want the fluids throughout the vehicle to move around. Oil temp to be brought up high enough to evaporate any moisture in the engine, is just one example of why.
 
Agree on trickle charger. Prolonged idling not the best way to keep battery charged. The condensation build up is less of an issue if vehicle is kept indoors as there is less temperature swing. Condensation occurs in engine when the engine gets cold (overnight) and moisture from air condenses onto cool metal parts. This gets removed when driving when the oil temp gets above the boiling point of water (which is lowered somewhat from normal 100C due the vacuum from the PCV system since it draws a vacuum on the crankcase). If vehicle is parked outside it gets warmed by sun every day and cools every night. So everything that is not fully sealed, "breathes" a little bit as the warmer air expands and pushes out, then as it cools, it sucks air back in. Moisture moves in and out with the air and can condense leading to water buildup. Slow process, but any water is not a good thing.

Not to say that this is immediately devastating because it is not. I have bought old equipment that has sat outside in the sun for years and the diesel engine still ran like a top. Sure it wasn't good for it, but didn't directly kill the engine, so don't overly worry about this kind of stuff. Just good to make mental note to avoid problems if you plan on keeping vehicle for a long time.

One idea on the trickle charger would be to charge it through the 7 pin towing connector as that would be easy to plug and unplug. I personally would not want to have to open and close the hood each time to hook up charger. Some trickle chargers have fast disconnects that you could run up to the grill and connect and disconnect there.
This is what I use on my boat. Wired terminals to battery and just connect and disconnect the quick connect when I take the boat out. Very easy.
 
The condensation issue and avoiding short drives idea has been around for ever but have you ever seen a car damaged by it? My sister lives 1/2 mile from work. She goes home for lunch every day so four 1/2 mile trips per day. She's been doing it for decades. My brother in law is a mechanic and says he has never seen an issue with the car.

For this occasion I would definelty recommend a charger but it may not even be necessary for just one week intervals.
 
How much idle is too much? I think thats just an opinion question really, who knows, right?

I think about turning it off while waiting in car pool for kids or when I know I'm idling more than 5 minutes.

I watched a video on youtube (yes, everyone has an opinion) where a mechanic was building a hemi and he did a comparison of the OEM oil pump and a bolt on hellcat oil pump. The OEM only had 35psi at idle like we see and the hellcat had 50, similar to 2k rpm. The pump limits psi to 100 so you don't have to worry about too much pressure. He believed this would help the lifter issue till at least double the miles on the engine.

I purchased 100k mile warranty. Sometimes I think of letting it idle more so I can get it fixed before the warranty runs out and other times I think of not pushing it. Like gambling or the stock market.. can't time it so don't try it.
 
How long does your Jeep sit on average? Mine "might" get driven twice a week on average but usually only once a week. We have never owned three vehicles at once and never realized how little we actually drive until now. When I or we decide to go somewhere we often choose the vehicle that hasn't been driven the longest. Sounds like I need to invest in some "more" smart trickle chargers.
Same here. I daily the JT and out of an abundance of caution would rather not take the 392 to work. So it sits until the weekend or the next week. It stays in the garage, but still don’t want to have a dead battery. Thank you.
 
All good points. Dealing with lack of hard facts. How much is too much? Is it the oil pump or splash lubrication that affects the cam? I don’t want any problems and avoid prolonged idling just in case. Higher rpm’s increase splash and oil pressure. 95 or more percent of these engines are probably going to be perfectly fine the way we take care of them (however that may be). Acknowledging that precautions and proper maintenance help but my dad was terrible with maintenance. Like over 10k miles sometimes on Dino oil and his engines outlasted the vehicles. But then again you can’t kill those 4.0 straight sixes with a hammer🙂
 
More than your battery is of concern. You want the fluids throughout the vehicle to move around. Oil temp to be brought up high enough to evaporate any moisture in the engine, is just one example of why.
Makes sense. Thank you.
 
There are engines you can idle and idle, without a problem. The i6 4.0 as the example @hardhat presented is one of them. Most modern engines don't do well with idling, especially the Hemi beast because it needs lots of breathing and lots of lubrication, and direct injected engines because of gunk build up.
 
Just make sure that you're in the garage with all doors closed while the rig idles.
My kids spent many hours on Yahoo Answers dispensing this type of advice. I'm hoping that no cats were actually microwaved, noone is missing appendages, etc.
 
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