Ok in the winter I let my truck run for at least 5-10 mins before I drive it to let the engine warm up a little and in the summer I let it run until the RPM's drop down. From what I've been reading lately that's not the right thing to do, apparently I'm doing more harm than good? What's everyones take on this? Am I hurting it more by doing letting it idle a little longer? I just thought when it's between 0-30* it'd be better to let it warm up and let the oil get to where it needs to be instead of turning the key and going.

 

Never heard if its right, wrong, or really doesn't matter, but i always warm my truck up for ~ 5 mins...

 

I think your doing more harm than good. It's OK if your doing so that your getting into a warm truck, but it's of no use to do it for the good of the truck itself.

 

Besides using fuel, what harm does it do to the motor letting it sit/idle that small time?

 

I let mine warm up in the winter too for a few.

 

Nothing

 

30 seconds ... TOPS.

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MGD

 

A friend of mine that would work on trucks said it is a good idea to let the truck idle for about 30 seconds before putting the truck in gear. He said it would help stuff last a hair longer because it pumps the oils and lubes before you start putting metal together under load (like shifting into gear). I don't know if that is true or not but I figure 15-30 seconds wont hurt anything, especially in comparison to sitting at a red light for a minute or two.

 

Your rings are designed to fit perfect when then engine is hot. In a cold engine they are shorter and stiffer, allowing more blow-by to get into your oil sump. That is why cold starts take a toll on your oil. Today's ring design uses the pressure of combusted gas to push the rings against the cylinder wall to improve the ring's seal in preventing blow-by. So then normal acceleration reduces blow-by during warm up.

Blow-by contains water, unburned fuel and carbon. They all take a toll on your oil, but the worst may be the build up of carbon deposits in ring grooves. Those deposits will interfere with the rings ability to seal, leading to more blow-by.

 

Looks like I won't have to worry about starting it early anymore. Thanks guys!

 

i let mine run til the rpms drop below 1,000. doesnt take long even when its cold. maybe a minute or so tops

 

My old truck took exactly 1 minute to drop to 800 RPMs and my 04 takes about 30 seconds to drop to 800. I think that's what I'm going to start doin instead of letting it idle for 10 mins.

 

i let my truck warm up for atleast 5 mins before i leave. not to mention you pretty much have to so you can defrost the windows.

 

Interesting thread, subscribing.
I usually let my truck warm up 5 minutes in the winter.

 

+1
The pcm transitions from the open loop cold start fuel table to closed loop at 30 seconds and enters cold drive away fueling. I warm up until I hear the rpms first drop ~ 30 seconds.