Rabbit

Well I was going to change the oil tonight so I decided to do a test. I started up the truck and the temp guage said 140. I sat there talking with my buddy for 15 to 20 minutes while the truck idled in park at regular rpm and I watched the temp guage move from 140 up to just above the "normal" mark in that time period. In my mind that is proof that the truck WILL warm up just idling. The truck wasnt dead cold but it had been sitting for about 3 hours before I started. The outside temp according to the overhead console 40f. Anybody else ever try this and have the same result?

MnTom

Yea, they do warm up SOME when idling. If you want it to sit and warm up, get yourself a stick and wedge it between the seat and the throttle to keep the tach reading about 1200 or so. The problem with not allowing it to warm up and get the cylinder temps up is the fuel does not burn completely and the resulting sludge causes some exhaust valve problems, could lead to possible turbo problems and makes a mess everywhere there is the slightest exhaust leak.
Tom

dieselnewbie

Seems to me you can't get into that much trouble not allowing the truck to fully warm up at times.

I always use high idle, either the cruise control buttons if it's over freezeing but under 50, or I just let the auto-high idle kick in if it's cold enuf to activate and I always allow it to fully warm up, or I drive off before hand.

But I can't be sure what the dealer does, etc. Last time I brought the truck in for service I know they let it idle for a long time because the MPG was way below what it was when I brought it in, so I know they had it sitting for a while.

That's a good test BTW, just before you drop it off for service, reset the overhead MPG and record it. Then see what it is when you pick it back up.

Anyhow, if these engines were so sensitive to the idleing issue, they'd be having all kinds of problems, due to it all the time.

I believe that things may get gummed up but I also think that as long as you bring it up to temp sometime afterward, or even work the engine so it gets hotter than normal, all the crap that may have built up will be burned off.

After all these engines are built to last.

Sidewinder

Is 40F considered to be cold?
I would have thought that it would be more of an issue at temps below freezing.

MnTom

It is not that big of an issue if you let it idle for 10 min and take off. When it does get to be an issue is when the temperature in the cylinder is not warm enough to burn all the fuel and the cylinder does not get warmed up to utilize all the BTUs in the fuel. I don't know what the 'magic' number is, but IF and that is the key word, if you let it go long enough it will produce problems. It does not happen all at once, but has a cumulative effect. I also forgot to mention that the unburned fuel has a tendency to wash the cylinder(s) and hasten the wear of the cylinder wall and the piston rings. It can and does drip into the oil and will dilute the oil too. So yes it is not good to idle them all day long, but it does not hurt them to idle some.
Tom

Holycack

I will tell you at -30 these trucks will actually cool down while idling. It will drop below the normal range just waiting for a red light to chage. now thats cool. Even running around town will not warm this truck up to operating temperature.

caper

Holy cow ,Holycrack are you sure your not stealing my identy, the only difference is that you have 4.10s, I live in Ft Mac now also . lol.

Dodge Demon

I have found that anytime its below freezing by 5 to 10 degrees they will not warm up no matter how long you idle,1200 rpms doesnt seem to do it either but hold the idle at 1450 rpm and even if its 40 below it will keep the interior nice and warm.

KATOOM

Did I just read what you typed right? You are saying you use the cruise control buttons for high idling? I didnt think it worked like that.

Mopar1973man

I've try it on my truck and it don't work... If it is a function that does work... How do you get it!?

J BODY

It works on the 04 to present. Our "old school" trucks only have a cold idle that is temp dependant and it also has to be enabled. 98 to around 2000 you had to flash the ECM and then enable the function with the DRB scan tool at the dealer. On 01 to 02 you could just enable the feature with the DRB. Works fine on mine, but it still doesn't warm up too quick. The stick and power seat method works about the best along with covering the radiator.

dieselnewbie

The cruise control method warms my truck up good.

It was ~27*F the other night and I turned on high-idle viea cruise control, tweaked it up to 1400 RPM and in 25 minutes the truck was warm as toast.

The CC method is good because you can vary the idle speed.

TXTad

Really?!

What's a DRB?

None of the mechanics around here (DFW) are all that familiar with the cold idle feature, so I've been reluctant to get them to enable it the couple of times I've mentioned it and gotten blank stares. Can you tell me what I need to tell them, or is it possible this is something I could do myself?

Thanks,
Tad

dieselnewbie

Go to this link and print it out, then bring it to the dealer.

http://www.dodgeram.info/tsb/2004/18-004-04.htm

I can't remember but I think this TSB (link below) has to be performed before #18-004-04, so bring this one to the dealer at the same time.

I believe this one:

http://www.dodgeram.info/tsb/2004/18-007-04.htm

has the software that allows you to use the cruise control to control idle speed, and the first one, 18-004-04 just enables it, but just print them both and bring them with you.

They'll know what to do.

TXTad

Yeah, but how about for my 2002?

Tad