Warm Engine Before Driving

I have received conflicting information. Some say don't warm up the engine before driving but move slowly for a few minutes. This method is not practical when I am leaving a rest area on the Interstate. Some people tell me to wait until the coolant temperature is at operating temperature. Which is the right way?

Yes. There are conflicting reports. Common sense is the best approach.

It's not good to start and go immediately. Internal engine lubricants need to flow a bit before adding throttle and load to the Engine.

A couple of minutes of warm time will suffice, unless it's very cold, allow for a few minutes more.

Letting the engine warm up until the coolant temperature is at normal operating temperature will sky rocket your idle % times and significantly decrease your overall MPG (which could get you in trouble).

Turn it on, let it idle for like 30 seconds and you'll be alright. The engine warms up a lot faster when actually driving.

I agree with G-Town on this.

I make it a part of my pre-trip inspection. After checking engine fluid levels and/or anything else I need to have my hands in the engine compartment for, I will go ahead and crank the engine letting it idle while I'm finishing up. Usually by the time I'm ready to roll, things have started heating up and I can go confidently on my way.

You're always going to get differing opinions on this subject. So you might as well settle on what you feel is best.

It's the same with "cool down". There is a fine line between wasting fuel and being proactive. The modern day deisel engine doesn't really like to be idled excessively.

Old School covered it pretty well. I might suggest that you allow about the same amount of time for cool down. Just a few min. After running on the interstate to let things cool down a bit.

I've noticed that my automated transmission doesn't like to shift properly from the low to high range when it's cold (heavy loads make it even worse), so I idle about 10m before I actually get rolling. The little bit over over idling doesn't have much of an effect overall.

I've noticed that my automated transmission doesn't like to shift properly from the low to high range when it's cold (heavy loads make it even worse), so I idle about 10m before I actually get rolling. The little bit over over idling doesn't have much of an effect overall.

Auto shift requires sufficient air pressure to operate. Never experienced what you described, many days this winter below 10' f. 5 min warmup is the max for me (per Diver's point).

You might want to get that checked.

Engine operating temperature has nothing to do with shifting points in any transmission, it's mechanical and hydraulic or air. I'll idle a cold motor to 100 degrees, then proceed with driving. The biggest issue is to get the lubricating oil moving around. The colder the oil, the slower it wants to move.

Engine operating temperature has nothing to do with shifting points in any transmission, it's mechanical and hydraulic or air. I'll idle a cold motor to 100 degrees, then proceed with driving. The biggest issue is to get the lubricating oil moving around. The colder the oil, the slower it wants to move.

Agreed. Exactly why UHC should have a mechanic check his transmission.