I have a 2002 F-250 Crewcab 4x4 V10. I have heard so much about this "Cold Start Knock". What is that???????

 

Could be referring to piston slap. A phenomenon that happens when the piston "slaps" against the cylinder wall when cold. The noise is caused by the piston skirt hitting the cylinder wall. Most times combustion heat causes the piston to expand to size and prevent the skirt from hitting. Unless, of course, you drive a Chevy.

I don't experience it.

Here is a good read about piston slap.

[link:www.canadiandriver.com/articles/jk/020320.htm|piston slap article]

You could be talking about valvetrain noise or the noise caused when using crappy oil filters, too.

 

My V10 makes a funny noise sometimes when I first start it on a cold morning. But "cold" is not real cold here in So Cal, maybe 50 degrees or so. How can I figure out what that noise is? It lasts for less than one second at start up, and it doesn't happen all the time.

Thanks in Advance.

 

What does the funny noise sound like?

 

It kinda sounds like a knock, but it happens so quickly and so in-often that it's hard to pin point. The first time it happened I thought it was me not releasing the starter fast enough. The next time I thought the exhaust system was hitting something. It only happens sometimes and at 4:30am when I'm half awake and late for work. So I can't really investigate. Maybe you could come over tomorrow morning and crawl under there while I start it. And keep doing this every morning until it happens again

 

Uh...yeah...I'll be right over.

Got coffee?

 

Got coffee you ask.

I have a new born baby girl at home and I get a couple hours of sleep on a good night. Sometimes I get no sleep. It's been this way since she was born on Sept 18. But all she has to do is look up at me and smile and it's all worth it!:-)

So, the answer is yes I have coffee, in fact I live on the stuff.

 

I get that occasionally.

Sorta sounds like if you hold the key on too long. Hear it about 3 times so far......

 

[updated:LAST EDITED ON 11-Nov-02 AT 08:48 PM (EST)]I get both of these noises. The key on too long sound only lasts about a second and not every start. It's been discussed here before. I think it was described as a "roar". Maybe a search for that will turn up the threads.

The cold start knock or piston slap has many threads here with lots of info. Mine does it when the engine is started cold, not necessarily cold outside. It does last longer in cold weather though. Varies from 3 or 4 seconds up to 10 or 20 seconds. I have seen people report that they have had the slap since their truck was new and now have 100,000 miles or more and have had no problems.

 

My previous truck was a Silverado 5.3L and belive me, I know what cold start knock sounds like... . That motor sounded like a washing machine for about a minute then after it warmed up it ran nice and quiet so I just learned to live with it.

But I am happy to report the new V10 in the driveway with 3K miles on it has made no such noises so far. The first few weeks after I bought it just starting it up and NOT hearing any knock made me smile.

 

>I have a 2002 F-250 Crewcab 4x4 V10. I have heard so much
>about this "Cold Start Knock". What is that???????

My dreaded 'cold start knock' sounds exactly like a lifter. It's only when the engine is cold, the outside temp doesn't make that much difference whether it's 40 degrees or 70 degrees outside. It still rattles for 2-3 seconds every morning when I fire off the beast. I have never heard any other V-10 knock so I have nothing to compare it to but I know what piston slap sounds like, and my V-10 doesn't make THAT sound, I think. It definitely makes the valve train noise although a couple people here had the noise and found a loose spark plug. I however did not have a loose plug, unfortunately. So I turn the radio up when I start it, and live with it. For $30-$45 thousand dollars each it wouldn't seem like we'd have to live with this does it ? I don't know about you but I work dang hard for my money, and it's pretty disappointing to spend that much money on your pride and joy only to have to listen to a motor knock every morning. Yea, yea it doesn't seem to have any adverse effects on it's longevity, but who knows really til we've owned them for 10 years. But do you really think Ford, or Gm is going to listen to one little voice whining about cold start knock ? Ha !! Come on Bill Ford Jr, you want us to believe your TV commercials about how great Ford products are ? Prove it, it's SO easy to talk the talk, but so few ever really walk the walk. Ken

 

My truck does is alot in the mornings too... at first I tought it was jsut the weight of oil I was using, then not enough oil, then well you get the picture... anyway when I get the "piston slap" it last for about a minute... Monsta is this normal?? (I'm guessing not) It is very frustrating and I don't have a clue how to fix it....

Brad

 

> My truck does is alot in the mornings too... at first
>I tought it was jsut the weight of oil I was using, then not
>enough oil, then well you get the picture... anyway when I
>get the "piston slap" it last for about a minute... Monsta
>is this normal?? (I'm guessing not) It is very
>frustrating and I don't have a clue how to fix it....
>
>Brad

How do you know it's piston slap ? I have a noise too, but sure sounds like a lifter clacking. Can you describe your sound to me best you can Please ? I'm just curious that maybe what I have IS piston slap. Thanks in acvance,

Ken 98 E-350 V-10 XLT 15 passenger Clubwagon

 

at risk of sounding like one of those crazy muffler commercials, my knocking sounds more like my pistons or lifters are slapping against raw metal... it sounds as though there is no oil in the engine for the first minute or so. After a minute or so, it goes to it's smoother sounding V10 rev

I would've made the sounds here but I would've probably just made a fool of myself (I do that fine without any help ) Anyway, I don't know if this answers your question or not Ken.. Anybody else have some good answers for us??

Its almost like telling the doctor "it hurts when I cough" could be lots of things and more than likely someone is just going to say "don't cough then"!!

BRad

 

2000 F250 V-10. Yeah, mine does it too. Always has. I only have 25,000 miles and it runs great otherwise, so I've decided to ignore it. It only last a second or so. I kinda think it might be injector noise.