Driving during high idle

[Alex S]

yup yup drive it lightly! i normally let mine warm up a bit at least till i can feel some heat out of the blower. Im pretty sure if someone grabbed me out of a deep sleep and forced me to to run a marathon with out my morning coffee and and a chance to wake up I would sure be pissed! and hurting so i aint going to do it to my truck!

 

[RLDSL]

To say that it doesn't hurt anything to drive on a cold engine is not exactly true, but this myth has been effectively spread by the environmental folks over the last 30 years to where most everyone thinks it's true now..but it's not, not matter how many times you repeat it.
Engines are designed to run while at operating temp, before that , metal clearances are wider on some things and they bang around a bit, pistons slap like crazy in their bores when cold leading to premature cylinder wear with excess taper, cylinder heads move around on the block when heating up and slide on the head gasket. A slow even warm up allows them to heat up evenly, but when put under load, they heat unevenly and flex all over the place and you get excessive movement on teh head gaskets which can lead to premature failures, I can go on and on, and I get my information from an old instructor of mine who was a past top bigwig at the Society of Automotive Engineers ( You know, that SAE you see stamped on everything ) amongst other seriously equally impressive credits

The environmental folks started the campaign to get folks to stop warming up vehicles and pushed detroit to make engines that you could turn the key and take right off without them stalling , but just because you can, doesn't mean it's a good idea. You will generally find the difference between engines that have gone a few hundred thousand miles on the factory head gaskets and ones that have had a set go every 150k or less , is the warm up time.

 

[Flagship]

Thanks all for the replies. I guess I was doing what most seemed to think is OK. In the summer, when it's in the 90's I don't give it too much warm up time, but in the winter, at or below 0, I do let it warm for a while, often till it idles down. My only problem is that by now, with me being used to winter, I tend to forget the truck still thinks it's cold out. My wife nags because I keep forgetting my coat. Don't need it if I let the truck warm up!

 

[bike-maker]

RLDSL is right on the money.
The statistic I'm remembering from my SAE certification days is that approximately 60% of engine wear occurs when the engine is cold.
Most modern engines use cast iron blocks, and aluminum heads; aluminum expands quicker and more than cast iron (which spurred mls head gaskets), so the head gaskets last for a number of heat cycles more than miles on the car.
I let mine run for about 5 minutes before driving it, then just baby it until it is up to operating temp. My main reason for this is it warms up pretty quick when driving, but takes forever just sitting in the driveway idling.

 

[towcat]

this is the very reason why buying a used EMS vehicle is a bad idea. Both operator and truck can be quietly sleeping on a cold winter night and all of a sudden the operator gets coded out. There is no luxury for letting the truck to "warm up". It's light the fires, clear the windows and put the pedal to the metal. I have two frontline trucks in my fleet that will kill the rings about every 150k mi. Between ballz to the wallz throttle use and extended idle times at the scene, rings don't last very long at all.

 

[OLDBULL8]

My daughter is a dispatch for EMS at a hospital, her Son (My Grandson) is an EMT there, jump in and go, although they are in a heated garage, all are diesel. What towcat is saying is so true. With 8 EMS vehicles, two of them are always in the garage for some repair every week. Daughter complain's at times they never have enough vehicals to do the job, specially when two or three are out on long trips, like Lima OH to Cleveland OH 320 miles RT.