2001 gmc pick-up

[flashback]

hope some of you gm experts can help me on this one.. I have a 5.3 v8 in my pick-up and on cold mornings when I crank it up it will clatter for 15-20 seconds. the dealership says this is normal for this engine and that it is just piston slap..I say JUST piston slap! I'm gettin up in years and i have messed with engines for most my life and in most cases if an engine rattles, something is going bad. so could this be true or is the dealer just packing my head......

 

[FLATHEAD]

Re: 2001 gmc pick-up

And this dealer thinks piston slap is normal???? When a piston slaps in one of my bikes its time for a bore and piston job. (top end)Pistons should not slap around inside that jug. I would check the compression.

 

[one more cast]

Re: 2001 gmc pick-up

We have a '97 chevy Lumina that also has early morning "piston slap,don't worry about it" that the dealer, and a friend of mine I might add, said is common now a days? It really sounds more like lifters to me and it goes away after about 5-10 minutes. The car is really not worth an overhaul and it has been doing this for a couple of years now and not getting any worse.I,m just gonna run it til it dies. This don't help you much, but at least you know your not alone.

 

[JasonJ]

Re: 2001 gmc pick-up

Some of the newer Ford trucks (97+) have been known to have piston slap as well, and the people are told the same thing, "don't worry about it". I would say just make sure to let it run for a few minutes until the noise stops, and hope for the best.

 

[bluewater19]

Re: 2001 gmc pick-up

After talking with my father. ( He is a Gm service manager and former Gm mechanic) he advised me that this condition is fairly common with the LS series motors and the new series of vortecs. He said they get the most complaints on the LS-1's in trans-ams.

 

[LubeDude]

Re: 2001 gmc pick-up

Ok, "Piston slap", Unfortunatly is a common condition with many different GM and Some Ford engines, But what I want to know is, Has it always done this? I notice this is a 2001 truck. Also is there any change in the first few days after you have the oil changed? I want to know what oil and weight you are useing too. Lets find out if this is indeed "Piston slap"!

 

[ndemge]

Re: 2001 gmc pick-up

Lubedube... I'm sure this has been asked before, but what do you do that you know so dern much bout 'erl?

 

[dhammann]

Re: 2001 gmc pick-up

There is an inexpensive remedy for this....it is called RADIO turn it up and quit worrying....it is normal for a reciprocating mass of steel to make some noise. The worst I have ever heard is the Ford in-line 300 cubic inch engine which will knock right past 200K miles!!

 

[LubeDude]

Re: 2001 gmc pick-up

Ive made an attemp at answering this before. I wont go into it in much detail this time.<br /><br />As far as the oil goes, it has been an obsesive hobby of mine for over 30 years. Ive researched and kept up with oils for all that time. Now with the internet its that much easier.<br /><br />Ive been involved in the automotive industry in one way or the other all that time also.<br /><br />Right now I am a Property Manager of sorts, but mainly take care of a rather large exotic and musclecar collection.

 

[ndemge]

Re: 2001 gmc pick-up

enough of an answer for me. thanks <br /><br />looksy at the time.... 4:30 on friday night.!<br />C-ya'll Monday!

 

[SpinnerBait_Nut]

Re: 2001 gmc pick-up

Would be interesting to know if it has always done this or just started doing it.<br />Did it start after doing something to it?<br /><br />Curious minds want to know.

 

[FLATHEAD]

Re: 2001 gmc pick-up

I have to disagree! piston slap should not be present in any motor that is in good condition. Piston slap typicaly refers to a piston that is sloppy in the cylinder and has room to to move side to side resulting in "piston slap" Or worn rods resuting in slap. Maybe I am wrong?? If I am would someone please explain to me why a piston would slap around in a cylinder enough to hear it inside the car and this is called normall??? I normally stay out of the tech stuff, but this one has got me going. With the motors I work on if you have "piston slap" you have problems.

 

[petryshyn]

Re: 2001 gmc pick-up

Piston slap is common to GM in the last few years. Shorter piston skirt design lends itself to piston rock (slap). Less dense block material also amplifies the problem as it doesn't absorb noise as older ones did.<br /><br />Couple of things to try before "throwing in the towel"<br />-decarb the engine. deposits are known to cause clattering for a few seconds till they soften up<br /><br />-install an OEM oil filter (has a check valve). Some aftermarket cheapies don't have one and can cause leakdown.<br /><br />I don't mean to alarm you, but I do remember a bulletin requiring engine bearing replacement on some older 350's strickly to reduce cold start knock. This may not apply to yours. . .

 

[LubeDude]

Re: 2001 gmc pick-up

Schematic:<br /><br />Good reply.<br /><br />I still want to know if this vehicle has always done this and what oil he is running, and if it does it just after he has had the oil changed!

 

[dhammann]

Re: 2001 gmc pick-up

Ford put out a service bulleten years ago on it's 300 six cyl. From day one it has noise from piston slap,timing gear back-lash and camshaft tingle. This has proven to be one of the most dependable engines ford has ever built! If the noise still exists after warm-up then I would be a little more concerned. Crawl under a fine Japenese car and put your ear close to the oil pan....you will hear plenty of noise. A big engine has more mass, hence louder noise.

 

[one more cast]

Re: 2001 gmc pick-up

lubedude, I'm not flashback but am interested in your test. My 3.1L chevy knocks "piston slap" less with new oil.I use penzoil 5w-30 and penzoil filters changed every 3000 miles. the motor has 114,000 miles on it and is never driven hard.

 

[SpinnerBait_Nut]

Re: 2001 gmc pick-up

Without knowing if your's is 2wd or 4wd etc.<br />There are some TSB's on this I have found.<br /><br />TSB# 01-06-01-028A<br />Put out in March of 03<br />Engine-Knocking on cold start-Explanation<br /><br />TSB# 02-06-01-038<br />Put out Dec. of 02<br />Engine-Knocking or lifter noise<br /><br />You could take them numbers to the dealer and he could look them up for you to tell you what they say.<br />Hope this helps.

 

[flashback]

Re: 2001 gmc pick-up

Guys, Thanks for all the input. it is much appricated..<br />LubeDude: I bought the truck in april of 02, it has always rattled if the outside temp gets below 35 degrees.. <br />Schematic: the deal about the skirts on the pistons is exactly what the dealer told me. apparently the skirts are very short so the piston slaps for a few seconds until it gets warm...<br />Bluewater: Does your dad say if there is any damage being done. I can live with the rattle for a few seconds in the AM. <br />SBN: thanks for the codes, I'll check them out..<br /><br />thanks to all of you for responding....

 

[LubeDude]

Re: 2001 gmc pick-up

Flashback:<br /><br />Could I PLEASE know what oil and weight you are using!

 

[flashback]

Re: 2001 gmc pick-up

Lubedude, engine has 60 thou on it, using castrol 10w 30. oil is changed every 3500 miles. thanks again for the info.......