Piston Slap!

[dr.gizmo]

NIH, Not Invented Here.

[FanOfDurant]

I would ignore it also, don't get me wrong. The question is "Why am I dealing with it in the first place?"

"My buddies 5.4L Ford doesn't do it, it's aluminum and cast?" "My girl friends Hemi doen't do it"

Why does anyone have to have piston slap too worry about in the first place? In today's day and age?

Exactly.

[doh]

Originally Posted by FanOfDurant

Exactly.

Thank You

[tom3]

Have to realize this noise is a product of piston design carried to the limit. Lightweight short skirt pistons, wrist pin location, skirt coatings, compression, engine management to maximize efficiency and lower emissions, and all that. A little cold piston noise is not an issue except for the perception it gives the "non-gearhead" public. The majority public that buys, or used to buy, GM vehicles. Thank goodness GM fixed it. Too late?

[GMCSonoma]

Originally Posted by tom3

Have to realize this noise is a product of piston design carried to the limit. Lightweight short skirt pistons, wrist pin location, skirt coatings, compression, engine management to maximize efficiency and lower emissions, and all that. A little cold piston noise is not an issue except for the perception it gives the "non-gearhead" public. The majority public that buys, or used to buy, GM vehicles. Thank goodness GM fixed it. Too late?

It is...sadly...


We all know if TMS had the issue...then the owrld would have accepted it with loving & open arms.

Being on the inside, I see it as a non-issue as it's generally something my customer base never approached. IMO, there are bigger issues to contend with @ the dealer level, especially when customers want a vehicle not just repaired, but "re-engineered" to their expectation---whatever that may be!

[Bow4elk]

It's really great to hear all the perspectives and gives me some peace of mind hearing from you professional mechanics. I'm running 5W-30 synthetic blend oil and using AC Delco filters. And I change the oil/filter every 3K miles. Given my mileage should I switch over to full synthetic?

Where I live the weather temps range from low 30's to upper 90's (give or take 10 degrees peak winter/summer).

Any thoughts on oil relative to minimizing slap wear in the cylinders?

[FanOfDurant]

Your oil choice is sound. Honestly I'd stick with it... You know, the 1 oil I've found that 'somewhat' helps with that sound is Valvolines Durablend 10w30. I've used them all and am generally a Mobil1 guy. I found this by accident really when there was a nice sale on the stuff so I picked up a case. Your oil filter has a good anti drainback valve on it and that's a big plus. Like I mentioned, we have these engines with 2-300k plus original miles and I know we never used the Durablend oil. Mostly Northland 10w30 for our work trucks. I just noticed the Durablend quieted my truck down. Just stick with what works for you.

[supra]

Just found GMI and joined. Looks like a great resource for GM/Chevy owners and I'm hoping to share what I've learned (mostly frustrations!) as a newbie Chevy Truck owner, and hear from experts who know the ropes.

I have recently learned about the infamous condition known as Piston Slap (www.pistonslap.com), and am trying to get the root of the matter in terms of:

1. Is it really a "customer annoyance" issue, as GM claims in there tech bullitens, or is is a time bomb in hiding? I come from a manufacturing background, and in my humble experience metal slapping metal is NOT good in any case, regardless of whether or not you find it "annoying", as GM claims.

2. What is the best approach to determine the severity of this condition?

3. What is the relative cost of a rebuild on a 5.7L V8 vs. a crate replacement engine? I'm not experienced in "big" overhauls such as this so I'm trying to weigh my options with keeping the truck or getting rid of it.

I own a 2001 Silverado with 98K miles. 5.7L, Z71, LT, extended cab. The automatic transmission just died and I put in a Jasper rebuild two weeks ago. That came out of nowhere as I just returned from a long road trip and experienced no issues, literally, until I pulled into my driveway. So, there's the only silver lining I could find

Other issues I'm frustrated with:

I bought it certified pre-owned from the dealer. It was a lease return, one owner, 53K miles. Right after the warranty expired (3 months) all this crap began (see list). Keep in mind, this truck had a 270 point inspection to get CPO status, according to the dealer.

- Dash lights started dropping like flies (55K miles)
- Power mirrors quit working altogether (60K miles)
- The gas gauge went haywire (57K miles - $700 sending unit repair – known GM issue, no recall or dealer fix)
- Piston slap (www.pistonslap.com) (80K miles)
- AC and/or heater core is failing (85K miles)
- Transmission died (97K miles)

Any inputs/advice/clarity is GREATLY appreciated.

Thanks,
Bow4elk[/quote]

I have a 2001 GMC 2500 HD 4X4 Long Box Ext. Cab
The 6.0 ltr. slaps like crazy in the morning but dissapears after a minute or so.
Started using straight syn. 5w30 about a year ago seem to help a bit.Most recent problem is back brakes and now drivers side power window regulator is not working.At 120,000 km wondering how long she is going to last.Great truck to carry a heavy load

Thanks Supra

[Ed753]

I had a 1999 4.8L thought I got a bad one, slapped when it was about due for an oil change and cold, started about 20K miles. I wanted a 5.3L because the 4.8L was fine around town, but pulling my trailer not so good. Anyway I bought a 2001 5.3L, it was twice as bad, started at 16K - then it started burning oil, (low level light would come on at about 1,500 miles into an oil change) I took it to the dealer, they said it was normal "they all do that" .... sold it within a week (with a warm engine) and bought a Ford.


The new engine design doesn't allow big enough piston skirts, that along with the "net build" vs. previously used "select build" cost GM a lot more than it saved them. I believe they stopped select build when they moved engine production from Flint to Mexico. Here is a little blurb explaining the piston fit.

Around 1998, GM switched from a "Select Build" method of manufacturing and/or assembling engines to a "Net Build" method, in order to save money on manufacturing and/or assembly. In the Select Build process, pistons and cylinders are matched for size and fit. GM's new "Net Build" method of manufacturing and/or assembly, in contrast, assumes all pistons will fit equally well in all cylinders and does not allow for variations in the size of engine cylinders or pistons. The pistons of slightly varying size (all within spec) are not individually matched with the cylinders of slightly varying size (all within spec).

[FanOfDurant]

Around 1998, GM switched from a "Select Build" method of manufacturing and/or assembling engines to a "Net Build" method, in order to save money on manufacturing and/or assembly. In the Select Build process, pistons and cylinders are matched for size and fit. GM's new "Net Build" method of manufacturing and/or assembly, in contrast, assumes all pistons will fit equally well in all cylinders and does not allow for variations in the size of engine cylinders or pistons. The pistons of slightly varying size (all within spec) are not individually matched with the cylinders of slightly varying size (all within spec).

I remember reading that awhile back.. Nothing like saving a few pennies here and there... I never understood that mentality. Is it worth all of the warranty pay outs? Is it worth losing lifelong customers and scaring off any potential new ones? It is worth tarnishing your reputation for quality V8 engines? Typical GM mentality... The same warped mindset that helped drive the company into the ground. I wonder if the issue has been permanently fixed now, or are we still using a band-aid to keep it quiet? I've heard motors as new as 07's knock Still.

[supra]

Any one having trouble with rear disc brakes on there pickup

[ChevroletTough]

I have an 04 Silverado (5.3L) it does have some piston slap in the mornings, when its cold out, but goes away after about 45 seconds of running. Nothing serious, just because its cold I've talked to a bunch of friends who have worked on these trucks (professionally) and say they almost always have piston slap, but its not the end of the world, the engine itself is very strong and a good one at that. I would fully agree.

[ChevroletTough]

Originally Posted by supra

Any one having trouble with rear disc brakes on there pickup

Mine don't let up as soon at the front ones do... might be the parking brake being a POS though.

[flctinman]

i'd rather have slap...then sludge anyday.

[smith7629]

Originally Posted by Ed753

The new engine design doesn't allow big enough piston skirts, that along with the "net build" vs. previously used "select build" cost GM a lot more than it saved them. I believe they stopped select build when they moved engine production from Flint to Mexico. Here is a little blurb explaining the piston fit.

Around 1998, GM switched from a "Select Build" method of manufacturing and/or assembling engines to a "Net Build" method, in order to save money on manufacturing and/or assembly. In the Select Build process, pistons and cylinders are matched for size and fit. GM's new "Net Build" method of manufacturing and/or assembly, in contrast, assumes all pistons will fit equally well in all cylinders and does not allow for variations in the size of engine cylinders or pistons. The pistons of slightly varying size (all within spec) are not individually matched with the cylinders of slightly varying size (all within spec).

How would a select build process work for the volume of trucks/SUV's/Impalas/Buicks etc that GM built through the 90s that had a V8? I don't see how they could possibly match each piston and cylinder for every engine.