letting your truck warm up

ive always waited till 1/4 of the tank of gas was burned.

 

I am really surprised that "modern engines" develop piston slap. I traded a '96 S10 because it developed piston slap at 30K miles. This slap lasted until the engine was at least part way warmed up. Last GM after years of GM vehicles.

Is it because they use short skirts to reduce friction?

Anyway, the reason I drive "gently" out of the lot is to avoid the slap. By the time I am out of the lot, wait for the light and am out on the road, usually in more traffic, the temp gauge has started to move and the slap is gone.

 

I still just wait till the idle drops down. Which is usually a minute or two maybe less, makes me feel better than starting and straight driving.

 

With the cold New England winter weather about to swoop down on us, I
have a queasy feeling in the pit of my stomach. Why, you ask? Because
every winter when my boyfriend and I get into my car, I start it, then
I put the car in gear after about 30 seconds and drive off. This
drives my boyfriend nuts, and I have to hear about "how bad it is for
my car" to put it into Drive before it warms up. He will start his car
and sit there for a good five to 10 minutes before he shifts into
Drive. My question is this: Am I really doing harm to my car by not
letting the engine run for 10 minutes? If not, how can I prove this to
him? I found an article in The New York Times a couple of years ago
that stated that nothing is gained by sitting in a freezing-cold car
while the motor is running before you shift into Drive. He thinks that
the reporter at the Times didn't know what he was talking about. But
he just might listen to you if you say it's OK. Please help! It's cold
here in Boston! -- Lisa

RAY: How do you prove it to him, Lisa? Hand him this column and ask
him to read the following aloud:

TOM: Dear Lisa's Boyfriend: You have your head so far up your tailpipe
on this one, it may be coming out your air intake.

RAY: How's that, Lisa? Will that do it? You're absolutely right, as is
the reporter from The New York Times. On modern, fuel-injected cars --
basically anything made in the past 20 years -- you're not helping the
car at all by warming it up for five or 10 minutes.

TOM: On older, carbureted cars, that kind of extended warm-up can
actually cause damage to the engine by diluting the oil with excess
fuel. So it's even worse if you have a really old heap.

RAY: But with modern cars, all you're doing with a long warm-up is
wasting gas, increasing pollution, raising the temperature of the
planet and making yourself 10 minutes late for your chiropractic
appointment. The proper procedure is to start the car. If it starts
and keeps running, put it in Drive and go. Go gently (don't back out
of your driveway and floor it right onto a highway entrance ramp),
because you'll be warming it up during your first few minutes of
driving, but DO drive it.

TOM: If it's bitterly cold out, like 10 or 20 degrees Fahrenheit or
lower, you can let it warm up for a minute or two to allow the oil to
thin out a bit and circulate completely. But other than that, if it
runs, driving it gently is the best way to warm it up.

RAY: So tell your boyfriend he not only needs to get off your case
about this, but he needs to stop warming up the car himself.

TOM: AND, to make up for all the misplaced grief he's given you over
the years, he needs to start going to bed 10 minutes before you do, to
warm up the bed for you on cold winter nights. That's a warm-up
activity he can do that's actually useful!

 

The piston slap is caused by the hypertuetectic pistons that they started using way back in the early 70's. I made the mistake of putting them in my '73 Coupe DeVille engine when I had it rebuilt way back in the mid 90's. I though they were the shit without going to the expense of forged because they actually used them in the early 70's LT-1 Vette's. Back then they were starting to be used as a cheaper high performance piston that was stronger and handled heat better than a standard cast piston but were far cheaper than forged. I should have done my research better.

Hypertuetectic pistons are far stronger than standard cast pistons but they are brittle and the horror stories about them over the last 20+ years are endless. Especially when used in race motors or hot rods that are run hard. They do have a shorter skirt and I believe a higher silicon content mixed into the aluminum. Unless the piston to cylinder wall clearance and rings are all set up just perfect you get piston slap until the piston warms up enough to expand and fill the gap.

My Caddy has had what I "think" is piston slap since the engine was rebuilt and recently developed a cold knock I believe is a piston. I won't know until I tear it down which will be a while. Still runs and idles like a new car once it's warmed up though. It takes a loooong time to get all that cast iron and those huge pistons up to temp especially in the winter.

The whole reason behind the idea of hypertuetectic pistons was to get a better bore, piston/ring seal for better emissions but as it turns out it just cost 10's of thousands of people some very expensive headaches and a whole lot of oil consumption.

While the piston slap really doesn't hurt anything eventually the piston can cock in the bore just a little too much some day and boom. That's the end of your engine which is why I made the post earlier about driving off with a cold engine while the pistons are slapping away. That's just asking for trouble. All that being said, you can have piston slap and the engine can still last 300,000 miles.

 

I do the same thing although I don't let it warm up for very long. Just until the idle drops down to 1000rpm or just below. I have to agree with what others have said here as far as the newer cars are concerned. As far as something like my Cadillac is concerned the NY Times is full of it. I've let that thing warm up for at least 10 minutes before I put it into gear and when it's -10 it idles for at least 15 or 20 before it gets to 180 degrees. For the last 130,000+ miles. I had an oil analysis done on it after 5000 miles on the same oil. There was NO fuel dilution.

As far as taking advice from the New York Times on how long I should warm up my engine, especially my old relic Caddy. Well, that is the LAST publication I'd take any advice from especially on that subject. I'd bet 90% of the people that work there take the subway or a cab and don't even own a car. I won't even go into their wacked out views on pretty much everything including a phony energy shortage and phony climate change that has never existed along with their dislike for the automobile and our freedom to drive where we want when we want in general.

That's all I'll say on that subject.

 

I could not agree more! Agrees with my theory about people who live on bodies of land surrounded by water or "ring roads".

And thanks for the detailed explanation. Interestingly, the slap appears more pronounced when the engine is soaked at 30 to 40 degrees. The few days we have had sub freezing weather during the day (here in Atlanta), I did not hear the slap. Must have something to do with the different coefficients of expansion for aluminum and cast iron.

The truck is garaged - I baby it - so no problem in the morning.

 

The few days we have had sub freezing weather during the day (here in Atlanta), I did not hear the slap. Must have something to do with the different coefficients of expansion for aluminum and cast iron.

That's bizarre. Usually the colder it gets the worse the piston slap is or at least it lasts a little longer. I don't know the make up of the pistons in the Toyota's but the ones GM was using for a couple of decades not only slapped a lot but they also caused the engine to use, not burn a ton of oil. Like a qt every 1000 to 1500 miles. A lot of those engines still lasted 200,000+ miles though. Some, of course, blew up.

My old Caddy is like that thanks to those damn hypertuetectic pistons. It has always used a qt every 1500 miles or so but it runs like a brand new car. Even with the bad cold knock it has developed once it warms up it runs like a new car. As a matter of fact it idles smoother than my Taco does.

 

YES, I DO , i always let the truck get to, minimally to the C mark on the temp gauge , but usually one mark over the C almost all of the time no matter what, then i drive gingerly until the needle gets to the middle and then just drive normally after that.. i mean, i never romp on my truck anyway, but i always let it warm up, yes.

 

I pretty much do the same thing. I don't romp on it constantly but a few times a week I take it up to 4000-4500 rpm and ring it out a little.

 

True that, they say thats good to do every now and again, get some of the carbon build up out lol

 

yeah i run my truck hard like every 2 or 3 weeks. but i dont run it hard for long. shift thru 2 gears about 4000 rpm. thats the hardest i ever run it.

 

This thread is weather specific .

Just this morning I had to run the truck for 15 minutes before I even considered trying to move it .About two feet of snow this morning and she wont grab 4x4 until the front axle spins for 10 minutes .
Any sooner than 15 minutes , the auto transmission clunks into forward gear , I have no power steering whatsoever , all 4 tires have flat spots and I can only see out the window through a 1 inch clear spot on the window .
The command start works great but the heated seats dont warm up with the command start , only with the ignition key .
And it,s not that cold yet hehehehe.
In a week or two , When its 50 below zero again, I will be programming the command start to run the truck every 3 hours leaving both block heaters plugged in while the truck runs

 

Good because that make no sense.

 

I only let mine warm up if there is frost on the windshield. Sometimes until it's gone or until I remember that I'm supposed to go somewhere. A few times I've let it run all night just to make sure I can get to work in the morning.
If it's not cold, I run it "easy" until the fan disengages then generally drive the pee out of it.

 

Not sure if serious.

 

That's fine for you, but I prefer not to waste fuel like that. A modern vehicle warms up faster being driven gently for a few blocks. If I can see out the windshield, I drive normally.

 

The owner's manual for my 2011 Ford Ranger said 30 seconds, any longer and you're just wasting fuel.

 

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AMG, I am going to have to agree with FoMoCo on this one. The world is surely about to end.

 

He very well may be. They do that in Wyoming sometimes. I've seen Ford F350's out in the Walmart parking lot idling while they go in shopping for an hour. In Alaska they never shut the trucks off out on the pipeline. They run 24/7. In some parts of the country and the world you have no choice if you want to go where you want to go when the time comes.