running cooler than normal

[HossDiesel]

I was just wondering if anybodys else dodge does this, This past week it has been around 40 here in oklahoma in the mournings and only 70s during the day and my truck is running about very cool, it was running around the 190 mark but now it is right around the frist line, is this normal? also, this winter i am going to let it idle alot somebody said it was bad for it, Is this true??

 

[BK]

yes it is bad to let it idle for an extended period of time.



The cylinders cool and wash down can occure,,, unburnt fuel getting passed the rings.



What's and extended period of time?

I haven't found a consitant answer.

In some readings I've found that you can idle it for short periods of time if the block temperature stays above 130degs (2nd mark). In some cool weather , while trying to charge my trailer batteries, I've found that leaving the air conditioner on full, loaded the engine enough to bring the engine temp up to and stay at 190.



If you search some threads on the board, others have created different "hi idle" mechanisms to bring the idle up to like 1300rpm or so and keep it there whenn they need to idle... . somewhere around there was thought to be a good rpm to burn the fuel and keep the engine toasty... .



There was a recent thread where one member used a idle selenoid (sp?) from a gasser to turn on and keep the "throttle" linkage at a hi idle at the fuel pump. He had posted pictures and all. . it was a very good post and one of the best solutions I've seen. Very clean.



I did a quick search. . some good reading on the issue...



https://www.turbodieselregister.com/forums/showthread.php?s=&threadid=24051&highlight=high+idle



https://www.turbodieselregister.com/forums/showthread.php?s=&threadid=23730&highlight=high+idle





And the one I was thinking of, I finally found it for you...



https://www.turbodieselregister.com...=&threadid=24502&highlight=homemade+high+idle



I rate this one a 10, for a driveway cure for the high idle issue

 

[HossDiesel]

Thanks ALOT for the info BK, i think i just might try that setup he has, looks like it would work really well for faster warm ups, and my extend period of time is leaveing it running wile i feed cows or go in and get something to, no more than say 45 mins or so.

 

[Chad Sheets]

A diesel will not generate heat unless under a load. You can hold it at 3000 rpm all day in cold temps and it will not build enough heat to keep the combustion temps where they need to be. Remember, a diesel takes in the same amount of air at idle as it does at full load.



Once the temps get into the 40's here, I cover the radiator up with a black piece of plastic I made with 1 small hole in the center for some air to flow, and another small hole over the aftercooler on the drivers side of the radiator.



Like BK said, if not enough heat is generated and maintained, the fuel will not burn completely and the result of that is washed out oil rings just for starters. Good luck, hope this helps.

 

[hammong]

I don't exactly agree with the statement that the diesel takes in the same amount of air at idle as it does under full load. What do you mean by "amount" of air? Under 30 PSI of boost, you're running 3 times the average barometric pressure, and consequently are taking in 3 times the amount of oxygen for any given volume of air that is processed due to the increased density. Furthermore, you're processing a much larger VOLUME of air as well - at 3000 RPM you're processing 3 times as much volume of air (regardless of pressure) as you do at 1000 RPM. In short? At 30 PSI (full boost with bigger injectors) and 3000 RPM, you're running 9 times the amount of air you do at idle. That's significant!



Now, our issue is really one of HEAT. To produce heat, you must burn fuel. To burn fuel, you must put your engine under some degree of strain. It's a good idea not to lug your engine or put it under undue immediate thermal stress by going from "very cold" to "very hot" in a "very short" period of time.



The best course of action is to start your truck per the instructions on the sun visor. Turn the key, wait for the "Wait to Start" light to go out, let the truck idle a little high for about 30 seconds to a minute, then take off. Drive slow and gradual, and keep your revs up above 1500-1800 until your block starts heating up. If you see BLUE or WHITE smoke coming out the tailpipe, you're not burning your fuel, and you run those risks mentioned earlier about washdown and fuel blow-by. If you don't see the blue/white smoke, you're NOT experiencing these problems.



Greg

 

[HossDiesel]

Hammnog, I do start and run like that in the mournings,just like you said but i only work about 3 miles from home and even when i stop and get something to eat it still never gets above the 140 mark, and i am not understanding the Idle thing, what about big rigs, they go for weeks wqith out shutin them things off and the leave them running all night.

 

[Rambling]

Maybe...

Hossdiesel,



I had a bad thermostat that stayed wide open all the time. I didn't notice it until the weather turned cooler. Couldn't get the heat up even with the radiator blocked.



Just a thought.

 

[HossDiesel]

Well,I went out and got a new thermostat and came home and pulled the old one out and one side of it was broken at the base and the gasket they gave me for the new thermostat would not work so I had to go back and get a new one and i went to put the new thermostat in and it isnt the right one sao after 2 hours i get one thats close and now i have a little bit of anitfreez running out along the base of the thermostat houseing, i guess i will just have to go to dodge and spend 45 bucks for a new one.

 

[DAWG-1]

Fan removal

Remove your fan and see how your temp is then. I removed my fan and found with the temps down in the 60 degree range and cooler at night, it warms quicker and is more stable. Today I was stuck at idle in traffic at 62* and did just go over the 190* mark . Will go to electric next. Sam

 

[Chad Sheets]

I did a pretty pi** poor job explaining what I meant. I was speaking in generic terms of naturaly aspirated. My fault. However... ... a gas engine of almost any kind runs on an almost always consistant 15:1 fuel ratio. 1 part fuel, 15 parts air. Sure it varies a bit, but it doesnt matter if you are idling in the driveway in grandpas Buick, running 150 in a Corvette, or cruising down the interstate at 65... ... . 15:1. With a diesel, you get 30:1 generaly at idle. During a hard pull, you might see 10:1 air to fuel ratio.



What I failed to explain the first time was that a diesel will always pull the same amount, if not more air if supercharged or turbocharged, than a gaser. All we do is get more fuel. In the case of "too cool", the more air being pumped in doesnt help the situation any.



End result is the same, a diesel relies on heat to ignite and run. If its colder than a well diggers a** out, then you can bet $$$ things are not going to warm up easy at all, and power will be down somewhat until heat is generated and maintained, which will not happen sitting and idleing, but driving under a load.



Hope this helps a little more, sorry for the confusion.

 

[TurboDog]

New thermostat maybe too cool

I have also noticed that after putting in the new part numbered thermostat that I seldom see the needle get to the first mark to the left of the 190 degree mark. That is just running around with out a load. Also with the onset of cooler weather, what is too cool a temperature that would be a problem. Do I need to block part of the radiator off to get the temp up to 180? Maybe I should try another new thermostat, seems they vary quite a bit.