I always let my engine warm up on cold days (i.e. days cold enough for piston slap) which is basically every day now. Do any of you with the cold weather slap just get in and go to save gas or do you let it warm up until the noise is gone (~5 min for me)? I just dont want to take the chance but alot of people say its normal and nothing to worry about, just get it and go.
I try to always let the truck warm up when it is under 30-40*F Even when I don't let it warm up I don't drive very fast and try to not go over 1500 rpm until I reach 160* and the slap goes away.
Driving a cold engine hard greatly increases engine wear.
When cold, engine parts are not the same size as they are when warm, and we must remember the engine parts are 'formed' for optimum performance when warm.
When first starting your engine no matter what the temps are outside, AT A MINIMUM allow the engine to slow down once the engine management system senses the O2 sensors are 'warm', thereby lowering the rpm from around 1400 to 950. Then put her in gear.
Most modern engine management systems will try to not allow you to 'get on it' until certain temperatures are reached, yet of course the nut behind the wheel can 'force' the issue (dumb dumb dumb).
As always, it is your engine, feel free to use or abuse it as you so choose. Talk to professional engine builders (REAL professionals, not shade tree guys or basic chippers/tweakers) as i do, ask their advice. Remember they look at engines every day of the workweek.
If i had $1 for ever race engine i have seen blown up at the track...
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Steven
2008 F-250SD 5.4L Off-Road 3.73
Track Only Ford Powered F2000 99/00 Van Diemen Chassis
Great point about letting the idle come down (I didn't realize it was O2 sensor based) before putting it into gear.
With every vehicle I have I follow the warm-up advice of a good mechanic:
1. Drive it gently until it's showing some water temperature
2. Drive it moderately until the water is at normal temperature
3. Drive it hard only after the oil is at normal temperature (if you lack an oil temp gauge, as most of us do, figure 3X the time it takes for the water to get warm).
Driving around my V10 in the cold I notice it shows 'warm' a lot faster than most cars. I think that the programming Ford uses for the "temp gauge" plus the fact that it's monitoring the cylinder head temps instead of the water temperature, throws the little guideline off a little bit. So I wait until about 2X the time it took the temp gauge has been to get to the 'normal' place before driving 'moderately'.
I put in Lucas oil in my 71 f250 and my 04 f250 diesel and I can say I feel a differents when I start them in cold weather. Even then atleast 15minutes of warming up for my Diesel, and even then I try to cruise 6 miles to the freeway.
2008 F-250 6.4L I let my truck warm up 10mim drive with care not to jam on it I do not get to much piston slap I find I get little better fuel milage out of it and use Royal purple great stiff
I let my truck "warm up" for at least 30 seconds. I have read that it is better to warm an engine gently, rather than let it just sit there idling. So I drive it gently at 1500 rpm in 2nd(standard shift) for about a mile cause I can. Somebody mentioned piston slap due to parts not being the same size as warm. Because of the gas rich enviroment in the cylinders when cold, some fuel can seep past the rings and cause a washing effect on the walls. And ther is other reasons to warm an engine gently and quickly. Last but not least an idling vehicle is hard on the enviroment. Block heater?,
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