I just bought my first new used truck! A 2002 GMC Sierra 2500HD duramax/allison. Now if I could only find the "perfect" travel trailer to tow with it! But first, I gotta learn how to drive it right. I know it's important to let the engine idle a little after long driving at high speeds on the highway. I know I'm supposed to let EGT get down below about 300 degrees. When I asked the mechanic who inspected the truck for me before I bought it he agreed that letting it idle "a few minutes" was a good idea. The owners manual didn't say anythying about it, though. So what's the general rule of thumb? After I've been on the interstate at...ahem..."about 65 mph" for a few hours, how long should I let it idle once I pull into a parking lot, for example, before shutting it off entirely? I'm not looking to put a stopwatch on myself, but I do need some guidance. Is a minute enough? 2? 3? What? If I take 2-3 minutes at say 30-45 mph from the exit ramp to wherever I park, does that by itself do it? Finally, one last question: is it a good idea for a newbie like me who wants to protect my $30K investment to install an EGT gauge? Thx
It couldnt hurt, thats for sure. Its always nice to be able to keep tabs on your motor. As for cool down, i really wouldnt worry about it unless you are towing something. Driving empty, by the time you got off the interstate, stopped at the end of the ramp, and then drove at low speeds for a little while, it would pretty much already be cooled off enough that you could shut it down. Oh, and congrats on the new-to-you truck :waytogo:
I would think that with a stock truck you shouldn't have very high temps when under normal conditions, but maybe when towing it would be a good idea. I don't usually let my truck idle for long, maybe 30 seconds at the most. A set of guages is a nice idea, especially with heavy towing in mind. A dual or triple pod with your EGT, tranny temp, and maybe fuel pressure?
It takes at least a few minutes to get under 300, even when empty. I shoot for 350, as that only takes 30 seconds. I also got into the habit of putting it in T/H as I get within a mile or so of my destination. Since this locks up the TC at speeds above 25 or so, as you decelerate it will keep the RPM's on the motor up and basically just pump air through it, which dramatically speeds up the cool-down time. If you're running synthetics especially, you shouldn't need to worry about it too much. The d-max uses a water cooled turbine, so coking the oil should be pretty hard.
