Warm up/cool down

[Jeepr]

My newbie questions are related to starting and shutting down. Sorry if this has been discussed before



The owners manual says at startup you should let it idle for like 3 min for the manifold heaters to finish. I assume that is what makes the lights dim. It goes on to say that if you drive before that, the heaters shut off. So, what is the implications of that? So, I should let it idle until the lights quit dimming? Thoughts?



What do people think about shut downs? If I'm doing everyday "normal" driving do I need to let it cool down. Does the 20mph idle cruise through my subdivision suffice?



I have to think there are a lot of diesels out there being driven like a gas vehicle, starting driving, turning off.



Thanks for any insight.

 

[donnier]

From what I have gathered, the rule of thumb is to idle for about two minutes to let the turbo oil cool down.

Another way is to install a pyro gauge. The temp to stay under before shutdown is 300 degrees.



If I have missed anything, some of the others with more experience should step in.

 

[Grizzly]

My newbie questions are related to starting and shutting down. Sorry if this has been discussed before



The owners manual says at startup you should let it idle for like 3 min for the manifold heaters to finish. I assume that is what makes the lights dim. It goes on to say that if you drive before that, the heaters shut off. So, what is the implications of that? So, I should let it idle until the lights quit dimming? Thoughts?



What do people think about shut downs? If I'm doing everyday "normal" driving do I need to let it cool down. Does the 20mph idle cruise through my subdivision suffice?



I have to think there are a lot of diesels out there being driven like a gas vehicle, starting driving, turning off.





You need to include your Signature so that we can get a complete picture of your question.

 

[TSpecht]

On the 2005 (and possibly other 3rd Generation trucks) the heater grids won't shut off until your speed is ~18+mph. If the truck is of a different vintage, I'm unsure what the logic is that drives the heater grids. But with the 2005 in my signature what I usually do when starting in cold weather is let it run at low idle for 15-30 seconds, then ramp it up to about 1200 RPM for another 15-30 seconds, at which point I'll start driving, but take it easy on the throttle for the first few miles.

Usually 15-20 seconds is long enough idle time after easy driving (no going up grades, hotrodding, etc, just a nice easy few miles of driving at the end of the trip) for me to feel comfortable about it. I usually let the pre-turbo EGT guage drop to about 250-260 which tends to take about that long in cooler weather. If you've been towing, racing or anything like that, then recommended idle time could go up significantly.

 

[JayWm]

On the 2005 (and possibly other 3rd Generation trucks) the heater grids won't shut off until your speed is ~18+mph. If the truck is of a different vintage, I'm unsure what the logic is that drives the heater grids. But with the 2005 in my signature what I usually do when starting in cold weather is let it run at low idle for 15-30 seconds, then ramp it up to about 1200 RPM for another 15-30 seconds, at which point I'll start driving, but take it easy on the throttle for the first few miles.



Usually 15-20 seconds is long enough idle time after easy driving (no going up grades, hotrodding, etc, just a nice easy few miles of driving at the end of the trip) for me to feel comfortable about it. I usually let the pre-turbo EGT guage drop to about 250-260 which tends to take about that long in cooler weather. If you've been towing, racing or anything like that, then recommended idle time could go up significantly.

What he said

 

[Jeepr]

Doh! Sorry, I did omit particulars about my rig. New 2005 SRW, 2500 CTD, auto transmission.

 

[Jeepr]

Sorry, but I'm still not quite clear on what is happening in the warm up process. If the heater grids run for a while, but shut off early if I drive away before they are done, then what is the implication of that? Is that hurting something? Or do they figure more heating will be happening from the engine working so the heaters aren't needed (i. e. , not necessarily a bad thing)?

 

[TSpecht]

The heater grids fire initially to heat the air up for reasonably good starting. They continue for 2. 5-3 minutes after the engine starts for emissions reasons and to help eliminate excessive smoke. It won't hurt anything if you start driving before the grid heaters have completed their cycle, although if you want the grids to complete their cycle, just don't exceed 18mph. IMO when starting the biggest thing is to make sure to let it idle or high idle for about a minute to make sure everything has gotten oil that needs it.

Besides, the engine will warm up faster if you're driving it as opposed to just letting it sit there.

 

[bmoeller]

What TS said. If it is really cold (less than 30*F), drive easy til it warms up a bit.



On shut down, it depends. If you were on the brakes holding a light, in drive, you may need to let the turbo cool down a bit more. Holding in gear will keep the EGTs up. Won't be as bad with a stock transmission and torque convertor, though.



This should help-

 

[2-ND TIME]

Warmup/ cool down

The important things that should be considered to me are. Oil flow to internal parts, warm up ( consider the rate at which metal expands, the temp outside, the time it takes for it to warm up ( for me after 15 mins I can still drive 5 miles and the temp needle will just be starting to lift off. will be fogging the cab for that time as well. )



on shut down: Even out head temp and have turbo below 300*f. The time it takes is flexable.

 

[Nate]

I fire it up, let it run for 5-10 secs and go. Shut it down at 350*. 250-260? :-laf I'd be idleing the truck for a good 5 minutes. If it's like -20 outside I'll let it run for a few minutes at startup though, but I'd do the same with a gasser.

 

[DaveHess]

I start my '03, idle it out of the garage, let her idle for the 150 seconds on the post heaters, and then drive her easy for about 1 mile. Unfortunately, as soon as I pull out of my subdivision I start pulling a grade on a two lane state highway. This morning it was 1 above zero so I drove very gingerly. Once I get home I let the pre-turbo EGT get to 250 before backing into the garage, sit one more minute, then shut her down. I run with a guy who bought his the same day as I bought mine. Almost identical trucks. He's a "warranty" kind of guy and starts driving his as soon as it stabilizes the idle and shuts it down as soon as he stops. Makes me nervous. Figures that's what warranty is for. I hope to never use mine.

 

[cojhl2]

I guess im from the old school.



I never drive a cold engine. Start it and leave,, come back when i think the heat gauge has started to move. In cold weather the radiator is covered with cardboard.



As far as shutdown every one is worried about the turbo. The other thing to worry about is cyl temp. If you been pulling it hard you gotta wait and let the engine normalize. The turbo gas (What the pyro measures) can be cool and yet the turbo and internal cyl temps can still be high.



If I have been pulling hard for extended periods i let it idle for 5 mins or so.



If you are cruising thru the suburbs at 20 mph shuterdown whenever you like. It cant be hot driving that easy.



The rule is:,, dont sit in the cab whilst you wait for heatup or cool down. . Get out and come back!!!



Thats my story and im sticking with it!!!