Piston slap

[gnilson]

My '01 Yukon sounds worse than a diesel for the 2 minutes after startup in the morning, then quiets down nicely. She only has 81k documented miles and I purchased a powertrain warranty when I bought her.

It sounds like the worst case of valve clatter you've ever heard, yet not really. It does not go away as quickly as the oil pressure builds. I've been told these engines have problems with piston slap, and that makes sense. The noise goes away as the pistons heat up and tolerances get tighter. Has anybody else run into this issue? What's the best solution? Ideally I want to pick up a fresh 6.2 shortblock and drop it in, but I think the warranty company will only pay for a new set of pistons.

Any thoughts?

TIA

Geoff

 

[Grocery Getter]

I've been getting some slap from time to time when my truck is hot.....and if I just shut'er down and start it back up it goes away.....suggestions?

BTW: Bout 150K on the clock

 

[ATL]

do you guys have the aluminum blocks? some 5.3 trucks came with aluminum blocks and they are notorious for piston slap when cold. but on the upside, if you decide to do a motor swap, people will pay a good bit more for the all aluminum motors

 

[chauncey0337]

I've heard replacing the o ring for the oil pick up tube will fix the noise. Also, some who use the 2 cycle oil say it alleviates most of the slap. Whether either of these works, I'm not sure as I haven't tried myself. Just throwing out suggestions.

 

[gnilson]

Thanks for the responses guys. I think I'll head over to my trusted Indy and have him diagnose it so I can begin the process of making a claim to the warranty company.

 

[rich5368]

Piston slap is common in these things. Mine has been doing it for the better part of 60k miles. Usually goes away by the time the trucks up to temp.

 

[04SS99Denali]

its normal for these motors and wont cause harm. turn up the radio and drive...

 

[Vinniety]

I have a 2001 z71 5.3 with currently 97K miles and since day one of ownership 4 years ago at 60K miles i heard that piston slap. Got worried when i first heard it but after research on line its a common thing for those years and motors.

 

[gnilson]

Ok, so even though I have a warranty, I shouldn't worry about it? Seriously? I'm thinking fresh engine on their dime, why wouldn't I do it? Seems like a no brainer to me. Maybe even squeeze a bigger block in...

Just sayin'

Geoff

 

[chauncey0337]

Do you think the warranty will give you a new motor because of piston slap, Something that GM says is normal?

 

[yukonic]

same here, i have an 01 5.3 and hear a little tapping only on cold starts for about a block of driving.

 

[04SS99Denali]

just thought id throw this out but if you think these motors slap bad you should hear some of the LS1's LS2's ive heard. crazy loud my LS1 in my camaro slaps till its warm also

 

[gnilson]

Do you think the warranty will give you a new motor because of piston slap, Something that GM says is normal?

You're kidding, right? GM says this is normal? Where? Is there documentation of warranty claims being denied? I would seriously be shocked. If this is normal, then why isn't it happening to every LS motor out there?

 

[Vinniety]

You're kidding, right? GM says this is normal? Where? Is there documentation of warranty claims being denied? I would seriously be shocked. If this is normal, then why isn't it happening to every LS motor out there?

This has been discussed for years and i cant recall finding anything that states GM is taking blame and they are going to recall all these motors. Here are a few web sites that might help you.

http://www.gmproblems.com/engine.htm

Below is a comment from someone on the web:

"I have been told by the GM training center that aluminum expands almost twice as much as cast iron. So the pistons have to be made smaller so they fit properly when warmed up. My 3.4 V6 has done the same thing (another engine with this congenital problem) since about 15,000 miles and has caused no trouble, I have 148,000 on it now. If it only make the noise for a few minutes cold I would not be concerned, almost every one I see in the shop has this noise. In fact I don't even notice it because because I hear it so much, it is just how these sound. I think this has been present in earlier times but the blocks were significantly heavier then and that muffled the noises better than today. Couple that with how much quieter todays vehicles interiors are and you hear things that you did not before. At 98,000 miles I would just ignore it and drive it, most likely it will never cause you trouble."

I have 97K miles and i have to say truck runs just as strong as day one. With so many people stating they have 200K and higher miles on these motors with that noise and the motor has never been opened that makes me feel a little bit better.

 

[chauncey0337]

You're kidding, right? GM says this is normal? Where? Is there documentation of warranty claims being denied? I would seriously be shocked. If this is normal, then why isn't it happening to every LS motor out there?

Of course GM says it's normal. You think they want to recall thousands and thousands of vehicles because of an engine noise.
Not sure if warranty claims have been denied but I've heard of GM extending warranties to pacify some owners. Most say it mainly occurs in aluminum blocks because aluminum expands 2x more than cast. Google it and prepare to be shocked.