So I’ve heard a lot of different inputs on this but I wanted some more experienced ideas. If I cold start my. 96 7.3 (let’s say 25-30 degrees) how long should I let it idle before actually driving? I’ll probably have it plugged in the night before on my timer for probably 4 or 5 hours unless I just don’t think about it. I also live about 2.5 miles from town so if I just need to run to there I normally take my 68 restore project because I’ve heard you shouldn’t start a diesel just to run it a few miles like that because it could damage certain engine parts after so many of these runs. Is that true? If so what parts would be harmed by short drives like this? This is my first diesel and I’d like to learn as much as I can about them so I’d appreciate the help!

 

Let it idle for how long after plugged in for four or five hours? Hell, I would say after you have oil pressure, voltage, radio set, seat belt buckled, and HVAC to your liking you are ready to roll. Not plugged in at those temps? I usually wait about 5 minutes, then cruise down the road. The colder it is out, the longer I would wait. Rare we get under 20F here, so I cannot say how long I would wait.

Short drives are hard on any vehicle. Diesel gets it worse as they work off heat, 2.5 miles would not even fully heat up my 300SD, let alone my beater Civic. The moisture will stay in the exhaust, the oil, brakes have limited heat in them at that point. More wear on the starting system and charging system. Take the long way into town and back if possible, the scenic route if you will. Could consider blocking off part of the radiator in cooler weather too, I do.

 

I try to drive at least 15 minutes and get to full temp when I use mine.

With block heater plugged in for an hour, mine starts up nice in the 20s and I just drive off

When starting cold, I do let it idle for 30 seconds to a minute until the smoke clears out.

 

Okay thanks. Yeah I normally just wait till the smoke clears up and I have everything set up unless it’s overly cold and I forget to plug it in I normally wait about 4 to 5 minutes before actually driving. I definitely wouldn’t mind the scenic route tho. Gotta love driving the 7.3 😁

 

If I started mine stone cold in the mid 20s, I would be waiting a long while for the smoke to clear.



#justweakcylinderthings

 

How long would you think maybe around 26ish? I also have a 1200 rpm setting on my tuner I normally use when it’s that cold

 

If its not bogging down, drive it but don't go full throttle

driving makes it work harder and that makes it warm faster

Start, let run while you scrape windows, drive it away

 

So that won’t damage anything as long as I’m just gentle till it warms up?

 

It won't harm a thing, as long as you stretch her legs once in a while when its up to temp.

 

Hey man! Well i am not the most knowledgeable on Diesels and i am recycling information from family members who are much more knowledgeable than me, and they have told me that if its plugged in you'll only need to let it run for about 30 seconds, which just getting ready and set to drive in the first place probably would take about 30 seconds (adjusting heating, scraping windshield, setting music etc) but if you forgot to plug it in or wasn't able to plug it in I've heard stuff from 5 minutes all the way to half an hour if its just off the glow plugs. However though if you pay attention to the temp gauge it never really goes up unless you're driving it. From what my family has told me, all you need to do is let the oil cycle after you started it, which would take about a minute or two (i leave it sit on high idle for 4-5 minutes just to be safe) and personally i don't believe that driving it short distances is necessarily a bad thing and my reasoning for that is UPS/FedEx drivers who drive those trucks 200FT to the next house and shut it off, then rinse and repeat. id assume after so many years of diesels being in existence that they wouldn't still have a problem like that. I don't really know but that's just my opinion/guess

After all take what i say with a grain of salt, because i personally don't have much experience on this stuff. I also bought my first diesel not too long ago (about a year now, also a 7.3)

Hope whatever i said helped! Enjoy your truck too man! its always a hoot to get your first diesel!
UPDATE: I asked my grandfather who is by far the most knowledgeable in my family on diesels (owns a lot of em too) said that as long as it isn't a super old diesel, you shouldn't need to warm it up for more than 5 minutes since it will never reach operating temp by just idling

 

I think what people are talking about when referring to short trips is starting your diesel and driving 2 miles to work and then shutting it off for the day and it never reaching operating temperature. UPS and the such get their trucks up to temp by driving hundreds of miles daily. Letting any vehicle get to operating temps at least a fair amount of the time is a good idea, keeps things nice and clean and condensation from forming.

 

Oh yeah that would make sense, and its always a good idea to get it to operating temps, but in the cold winter months letting it idle wont do too much unless its sitting there for a long time, but if he has time to spare or could set an alarm half an hour to an hour before he actually has to leave to go and start his truck, that would be the best option. Personally i start my truck on my last break about 15 minutes before i clock out, and by the time im done its warmed up enough to get to driving.

And yeah i suppose i didnt think the UPS thing through very much, and they probably leave em plugged in when they first start it.

I guess everyone has their own opinions, id suggest for him to let it warm up since it wont hurt to do it and saving you the potential cost of repairs is always a good thing. good points man!

 

Makes sense. Yeah if i Plug it in I’ll just get all set up and take off. But I’ll idle about 5 minutes if I don’t plug it in if it’s cold. And that’s a good point about letting it get to operating temps at least for a while. I normally stretch her legs a little after a few miles because who doesn’t love a straight piped 7.3??? I appreciate all the thoughts and help!