Idling in the winter

old wise tail only true for PRE egr truck's need to have the idle bumped up
older trucks will not hold temp at low idle
newer EGR trucks don't need to have the idle bumped up because the egr system will keep the temp up.... my owner manual even saids NOT to run the truck at high idle
even at -17 at low idle my truck stays at 180
if you have the right amount of anti-gel in your fuel for the outside temp it will start

 

Well, there is some credence to the notion that keeping RPM's bumped up a little when idling has more to do with keeping high enough oil flow moving thru bearings and such. There have been instances of excessive idling at normal idle RPM's leading to spun bearings. No, I wouldn't say it is a common occurrence, but there is enough evidence to suggest that it can be a risk. I guess each person has to determine for themselves the level of risk they are comfortable with.

 

Dead idling will cause motor damage. Everyone in my company from the mechanics up to the upper management wants us all to idle the CAT's to at least 1000 rpm regardless of the temperature and the Paccar's to a variable idle speed depending on the temps.

They don't care if it uses more fuel. They'd rather pay the extra $15-20 a day than the thousands to repair the motor sooner.

 

my truck has 1,155,993 on the clock and at low idle has 37-40 psi oil, more than enought and oil samples show NO fuel in the oil after 20,000-25,000 miles
IF my truck had low oil psi at idle (under 20 psi) i might think about bumping the idle up

 

If I had no option for plugging in, I would opt for a Webasto or Espar fuel fired coolant heater. Can be set on a timer and have engine coolant at 130F in a little over an hour. Not a long return on the investment with the fuel saved.

 

First off... @flood what engine do you have? They are all different in their needs. Volvo engines do not need to be idled up because of the design of their oil system, volvo keeps good oil pressure even at idle. the only time a volvo idles up (clean idle mode) is when it needa to heat the exhaust as its building too much soot or needs to build heat to keep from slobbering. newer trucks only.

you bump up your motor for a couple reasons.

1. As @NorthernMechanic said, you will dilute the oil with fuel passing the rings. You will also slobber oil through the exhaust and this is because there is not enough heat to properly expand and seal everything.

2. most importantly in your engines case. You will nor have enough oil pressure to effectively lubricate the top end.

This is why it applies to you more. You have a CM870 which is a dual overhead cam engine. Cummins had problems with the dohc engines eating cams for breakfast so after the cm871 they switched to a single cam and upped the oil pressure. The 870 is a low pressure engine at the best of days. You WILL burn out your valve cam and rockers if you haven't already.

I had to idle a lot last winter at base idle due to cold oil I was unloading and needed to run my pto slow. I did a overhead before and all was fine. I thought if I ran a synthetic then I would be fine. Nope! burned out the cam and 4 rockers.

1000rpm for short idle times, 1200 for long idle times.

https://quickserve.cummins.com/qs3/pubsys2/xml/en/bulletin/3379009.html

Cummins recommendation for operation in cold climate.

 

Why would you idle whole weekend. If your batteries are ok, you should have no problem staring you engine unless it's really cold.That single digit or lower. Just make sure your fuel is good, and you're good to go.

 

I had to do that a few years back. was a stretch where it was -30 to -50 Celsius so the truck never shut off. burned a lot of fuel. I finally got a Webasto and I use that for the bunk and engine. I'll only idle the truck at -30 or colder.

I just bought a dual Webasto engine and bunk system for $2100cdn for one of my trucks. not too expensive.