Idleing on cold mornings

[jlwelding]

I dont mean to high jack but am I understanding it right when you say dont let it idle long? You say go ahead and start lightly driving to keep build up from forming? And is this build up in the form of fuel in crank case?

[Mopar1973Man]

Typically it forms on the valves stem and its a tar like substance and eventually gums up the valves till it starts slapping valves with the pistons and/or bending pushrods. Build up of fuel in the oil would most likely be a bad injector leaking.

[jlwelding]

And this is from Idleing?

[Mopar1973Man]

Yes sir...

Symptom/Condition: Extended idle operation, especially in cold weather, can lead to stuck valves and bent push-tubes due to insufficient cylinder heat. This allows varnishes/oils to condense on the exhaust valve stems, leading to stuck valves, and damaged valve train components. A new software feature, enabled or disabled through the DRB III (See instructions under Repair Procedure), reduces the chance of valve sticking and improves cab heat warm-up time.

Right out of the TSB from Dodge...

[jlwelding]

Would hooking my grid heater back up be a smart think to do? Also what would be a good warm up time before HWY operation?

[Mopar1973Man]

I've got less that 100 feet to the highway... I might idle for about 1 minute and get rolling but I'll take nearly a full mile to get to 55 MPH and then hover there till the engine makes it to 160*F (lower end of the normal range) and then kick her in the ribs and get with it.

[ISX]

I said this in this post so I shall say it again.

Yeah personally I am on the road before a minute passes. Might take me a 1/2 a mile to hit 55 but as much power as these things have its not like they are being worked that much more driving especially if it takes a half a mile to get up to speed. Mike said a couple threads ago that the 3 cyl high idle and exhaust brake use 6GPH which was 9.1mpg at 55mph and since we get 20mpg+ at 55, that means you use less than half the fuel, so if your gonna load the hell out of it with the exhaust brake and 3 cyl, then what difference is driving it.. Another thing is that the high idle is what, 1200RPM?.. 55 is around 1600.. I don't think 400RPM more is going to be detrimental. I do understand that the engine needs to be preheated a little bit and let the oil get around. One guy I know was telling me about some engine he saw that demonstrated how long oil takes to get to everything and he said it took a while (maybe 5 min) but that was idling and the oil pump runs off of the engine so the faster it goes the more oil it is going to push. I say if it is under 0F, let it idle for 2 minutes, if it is 0-20, 1 minute, any warmer and 30 seconds. Remember that I don't mean get in and floor it, I mean wait that long then slowly proceed up to speed. If the speed you are going to happens to be interstate speeds, add 30 seconds to the idle times. A cold engine is not going to be happy about an instant 80mph.. Generators are very interesting in how they work and I am surprised that they do work like they do because a lot of the commotion about trucks is thrown out the windows with generators. For example, a lot of generators for backup have a governor that is set at one speed, wide open (or redline I guess is a better term lol). Yes, the thing will start up floored and stop at redline, there is no idle no nothing. I don't remember the standards on how long they have to start providing power after the power goes out for backup system but it isn't long, maybe 30 seconds. That means 30 seconds to crank over and get to proper RPM for 60Hz and start making power. The smaller generators (maybe 100HP) that I saw transfering were doing it in 10 seconds flat.

[Mopar1973Man]

Like ISX said I typical fire up and head for the highway and take it easy till I hit the lower band of the normal mark (160*F). The only time I use the high idle really anymore is if I'm being lazy and want a warm truck to jump in so I'l fire it up set the high idle and exhaust brake then come back in the house and the grab my stuff for the day and head out. Even by then most times the engine coolant is up to 100*F and the slightly warm air is coming out of the vents. But like ISX pointed out high idle does consume a large amount of fuel while loaded with the exhaust brake on.

[jlwelding]

So hook up grid heater back up to help with warm up. Even though it kills the batts and hard on regulator.

[Mopar1973Man]

Actually the grid heaters are helpful to get it to fire on all 6 cylinders. But it does nothing for warm of the engine being that after 2 minutes its cancelled anyways (ECM timed out) or if you exceed 20 MPH it will shut down. What it all comes back to is the EGT's temps pure and simple... If you got better than 350-400*F it will burn clean... Below that its just too cold for idling...

[jlwelding]

I have been on jobs where it was just flat out cold and would leave truck idleing to have a little heat. I guess no more of that.

[LiveOak]

If your truck is equipped with an exhaust brake, you can set the exhaust brake at idle and it will raise the EGT about 150 - 175 degrees. This is usually enough to keep the engine temp up during extended idling but in extreme cold temps, this may not work.

[Prowelder]

I have been on jobs where it was just flat out cold and would leave truck idleing to have a little heat. I guess no more of that.

You could add a High Idle System so you can idle the truck to prevent any problems. I always give mine 10-15 minutes to warm up in the morning. Then I drive easy until it warms up. It may not be necessary but we've got a lot of high milage cars around here and all of them are fine under the hood.