Question about piston slap...Does it hurt the engine ?

[yamaha94]

i also have a 200 sliverado 4x4 with the 5.3. and yes i have the piston slap, my theory is that in the 5.3's have short skirt pistons, thus when cold the pistons will move a little causing the noise, ive tried different weight oils and different filters nothing helped. if anyone has anyother ideas that would be great, and one ,ore thing, my OBD port isnt working i used my scanner on a 2004 trailblazer and it was fine but on the truck it acts like it has no power coming from the port to the scanner? anyone else have this problem?

[realotor]

I just spent about $9,000 having a GM dealer install a new HT383 crate motor in my 99 C3500 duallie pickup. The engine has piston slap so bad that it sounds like a worn-out Cummins diesel and belches black smoke when it starts. With any load at all on the engine it sounds like it's about to blow itself to pieces, so I don't dare put my foot into it at all when climbing a hill or accelerating from a stop light.
As for towing a trailer (the reason I bought the GM engine in the first place) it's impossible.
The engine has pretty much destroyed the value of my truck, which is otherwise in like-new condition. Nobody would buy it -- including the GM dealer that installed the engine.
What is GM's response to this? Tough. They all do it. It will go away eventually. Drive it for two or three years and see what happens. This is normal. Blah blah blah.
If there really is some secret warranty on these engines, I would sure like to know how to pry it loose. As it is, I now have a truck that's useless. At least with the old 350, it started, ran smooth and quiet and didn't burn any oil. The new engine is a pig.
This thread started with the question, will piston slap hurt the engine. I don't know. I only put 200 miles on mine before I parked it, but I can't believe that an engine that generates internal noise like it's being sledgehammered isn't being damaged.
Oh yeah: The engine is so hard to turn over, even with dual batteries, that it fried the starter, one of the batteries and the wiring harness. Another $800. But this is "normal."

[j cAT]

[quote=realotor;5954564]quote]

thanks for your dealership experience.
this is exactly why I would never recommend these businesses to do any work on an older vehicle...

replacing an engine should be basicly simple process, but with improper care can be damaged easily....

you should at least sue them for installing a defective engine...
this is something that will require some work , but 9,000 is alot for an engine replacement ,,,another reason not to use these theives..high cost poor performance.....

I hope you will get this resolved.....
dealerships are in the business of selling ....not repairing ,,,,10year old vehicles....vehicle owners like you are the reason they will soon be shutdown...that will teach him to buy a new vehicle !

[realotor]

[quote=j cAT;5955029][quote=realotor;5954564]quote]

thanks for your dealership experience.
this is exactly why I would never recommend these businesses to do any work on an older vehicle.quote]

An update on my hammering HT383 crate motor:
After dozens of phone calls, I finally tracked down the local GM Canada zone manager. Although the dealer was claiming that GM was refusing to do anything, the zone manager said he'd never heard of the problem, and promised action.
He was as good as his word. The next day the dealer called and arranged to bring the truck back. A couple of days after that, the engine was in a local machine shop being bored out. Then it will get new pistons with a longer skirt.
The machine shop says all eight cylinders had a piston-wall clearance at least .007 over the factory specs, which are loose to start with. And then there's the teflon coating that will wear off.
Bottom line: GM is refusing to admit any fault, but they are doing the repairs.
So I gotta wonder -- do dealers just make up this stuff about GM refusing to honor warranties?

[J-Ri]

I do not trust the service writers at most dealerships at all. I had to reprogram my PCM after installing a supercharger. I took it to Mike McGrath Chevyland in Cedar Rapids, Ia to start with, and the service writer assured me that the update would take all day. He tried feeding me some BS about downloads not working later in the day, so he needed to have it there when they opened. Had the feeling I would have been charged 8 hours for a 1 hour job. I could also say some bad things about customer service at every dealership in town that I have had to get parts from. The things I've overheard while wating in line... Anyway, I ended up driving 20 miles west to a small town dealer who charged me for an hour of work and had great service. That guy actually asked me how I was that day, the guy at McGraths acted like he was doing me a favor by talking to me, and actually answered the phone while he was talking to me!

I may be wrong, but I'm pretty sure there is a lot of paperwork for warranty work. We have a few pages that have to be filled out to make a labor claim on a warrantied part, and that's for just a few hundred dollars in most cases. I would guess that the service writer just doesn't want to do the paperwork, so he just tells the customer some BS about why it's not his fault and lets the customer pay for their mistake.

I must add, however, that doesn't mean the dealership technician is bad. After all, we have one here that can ban us! But seriously, there are great independent technicians and there are incompetent dealer technicians. There are great dealer technicians and there are incompetent independent technicians. Dealer doesn't mean good and independent doesn't mean bad. While I personally don't understand why someone would pay $30 or more extra per hour for the same work, there's nothing wrong with going to a dealership for service. It's your money, spend it where you want.

[j cAT]

[quote=realotor;5972874][quote=j cAT;5955029]

Originally Posted by realotor

quote]

thanks for your dealership experience.
this is exactly why I would never recommend these businesses to do any work on an older vehicle.quote]

An update on my hammering HT383 crate motor:
After dozens of phone calls, I finally tracked down the local GM Canada zone manager. Although the dealer was claiming that GM was refusing to do anything, the zone manager said he'd never heard of the problem, and promised action.
He was as good as his word. The next day the dealer called and arranged to bring the truck back. A couple of days after that, the engine was in a local machine shop being bored out. Then it will get new pistons with a longer skirt.
The machine shop says all eight cylinders had a piston-wall clearance at least .007 over the factory specs, which are loose to start with. And then there's the teflon coating that will wear off.
Bottom line: GM is refusing to admit any fault, but they are doing the repairs.
So I gotta wonder -- do dealers just make up this stuff about GM refusing to honor warranties?

this is how they confuse you they say its the other guy...when in fact the dealership is trying to cover their azz,,,with GM ...

gm and these poorly spec. engines is why piston slap is very variable some no slap others slap to destruction...I think I posted earlier that my engine slowly developed a slight slap when cold after the 36,ooomi warrantee period....still its not noisy...

you would think by now these engines would be fixed to the correct spec...! Its no wonder their going bankrupt,,,they and the dealerships over the years pissed off too many owners, with their take it or leave it attitude...

I hope you will get this all corrected...you never know...

[willywilds]

piston slap it can be fixed!!

it cost under $500 bucks and it only costs that much because of the amount of labour that goes into fixing it as they need to take the pistons out and reline them.

but getting it fixed does nothing to the performance it just gets rid of the horrible noise..
but the noise should go a way when the engine is warm and the pistons have expanded to fit in perfectly..

[kerisvery]

I have a 1996 Geo tracker with 236,000 miles on it . I bought it new and change the oil every 3000 miles. After 20,000 miles I started using TUFOIL at every oil change. I also use regular motor oil. The motor doesn't use any oil and is quiet. I did replace 2 timing belts one at 100,000 and one at 200,000 miles. They are external and recommended replacement is 100,000 miles. I recently bought a 2001 buick century 3.1 engine with 27,000 miles from my 91 yr old aunt who can't drive anymore. It has severe piston slap and never completely goes away even when hot. I had it checked at 3 shops in the area and was told to replace the motor with a rebuilt one for about 3k. I then replaced the oil with mobil 1 and it got a little quietier. After about 1000 miles I added TUFOIL to the oil. After about another 1500 miles the slap went away when warmed up. I am really impressed with this combination. It still has a faint noise at startup but after 35 seconds its completely gone. I now use one 8 oz. bottle of TUFOIL at every oil change and the motor now has 126,300 miles on it and runs great. The cheapest price I found for tufoil was on e-bay and the mobil 1 was at advanced auto parts.They run a special with the filter included. I replace the oil every 5000 miles since using this combination. I hope if you try this it helps you like it did me,good luck.

[chad1966]

I also have a blazer, which I believe has developed the piston slap. Well it didn't have it when I got it a month ago, but now with the cold mornings it does.
Blazer has 118k miles and runs great otherwise.
About the Tufoil from above...I have used it on my last 3 cars. Currently my 89 Camaro has over 200k on it, still going. Not like one with 100k but still going, uses very little oil, engine is still quiet. Camaro did have over 100 when I bought it (v8-305), but I did use tufoil and usually synthetic oil over the years. May have lasted this long anyway?
I will get some (tufoil) for this vehicle when I change the oil in a week or so, you save a few dollars ordering from ebay, ( the 8oz bottle)
I have also used their general purpose oil, lubit-8. Very satisfied with it, used on pc fans, locks, guns, car, etc. Very resistant to cold/heat.
Chad
2000 Blazer 4x4

[kerisvery]

One other thing I want to mention is use the mobil 1 synthetic oil and use the weight the car calls for with a bottle of the tufoil.I also mix 4 oz. of marvel mystery oil with every 10 gals of gas to help lube the upper end. I add it every other tank but you can add it with every tank if you want to. I see that tufoil on e-bay motors is the cheapest. You may want to add a bottle of tufoil with every oil change like I do in my buick with the piston slap. Keep me posted.

[j cAT]

Originally Posted by kerisvery

One other thing I want to mention is use the mobil 1 synthetic oil and use the weight the car calls for with a bottle of the tufoil.I also mix 4 oz. of marvel mystery oil with every 10 gals of gas to help lube the upper end. I add it every other tank but you can add it with every tank if you want to. I see that tufoil on e-bay motors is the cheapest. You may want to add a bottle of tufoil with every oil change like I do in my buick with the piston slap. Keep me posted.

I never used the tufoil ,,so I can't comment on that product ...the marvel mystrey oil I have been using for a couple of decades now...in the fuel and if necessary in the oil...this product made my 1983 chev. last and run like new till it was sold in 2000..the engine had 380,ooo mi and when last tested for emissions put out less than new 2000 vehicle..the inspector at the emission testing couldn't believe it...the carb/engine never any work rebuid etc...just the typical tune up stuff...

also I might add never had any oil leaks...even on the vehicles I have to this date...

with the new injector engines the marvel lubes and cleans the entire fuel system and does this with no damage...

some swear by seafoam...this is more a solvent too harsh for me to test out...

[Xpertlogo]

Hi I have been running my Malibu with 3.1 and annoying piston Slap in the morning, now I have to tell you my engine is running very smooth and the pston slap has disapeared, this stuff was amazing I placed 2oz of (Link removed by Moderator) in my engine and it just disapeared, I was so amazed by the performance and increase in horsepower of my car.

I showed my father the results and added the product for his 3.1 and his piston slap just disapeared also. I tell you guys if you have a piston slap give this stuff a try you have no idea just how much cahnge and quiet and smoother running engine. greatest thing about it is you apply it once and it stays in the metal somehow even after oil change. You won't be disapointed.

We live in New Brunswick Canada and in the cold morning around here and you have a 3.1 well it's gonna knock.

[MagicRat]

.
Hmmm....... spamming an on-line sales site here is not allowed as per the AF User Guidelines to which you agreed when you joined our forum.

BTW, if that stuff is so good at fixing piston slap, why is that claim not made anywhere on that site? Considering the site claimed the stuff did everything except cook your dinner, I would have thought piston slap prevention would be included too.

In fact the site specifically says it will not fix piston slap because it "will not affect factory clearances"

Lying and spamming gets a ban. Yes, I know your claims are simply "anecdotal evidence" which does not constitute a promise of performance. But I still say it's misleading.

Finally, it's funny that the mailing address for that site shows its located 10 km from Caraquat, your home town. So, it wouldn't be a family business or your employer, would it??

[speleocaver]

Looking up the causes for piston slap and found that it is the primary lack of silicon in the aluminum that makes up the pistons. GM uses 7% the good pistons use 14%.

Quote:
Early in the peace it was common for US forged-piston materials to contain only 7 per cent silicon in their make-up. This led to high temperature expansion rates, making engines sound 'rattly' when started cold. The Germans came to the rescue here with new materials for forged pistons which did away with the undesirable expansion rates, by containing a much more acceptable 14 per cent silicon content. As some top-level German cars have forged pistons standard (BMW V8, V12 ect) it was a requirement that these engines remained smooth and quiet, even when cold - hence the development of better materials. Now, a lot of the aftermarket forged-piston manufactures have caught on and are offering the 'quieter' high silicon content alloy.

With Hypereutectic pistons, the primary reason for having all of this free silicon is to reduce piston ring groove wear. This allows piston designers to move the top compression ring much farther up the side of the piston (where combustion temperatures are much hotter), and run much smaller, thinner piston ring lands (the metal section separating the ring grooves). The reason piston designers want to do this is that it allows a lighter piston to be produced, and also has dramatic results in changing engine emission characteristics. As emission laws become tougher, it will be commonplace to find true Hypereutectic pistons in road engines. It must be added though, that Hypereutectic pistons are not automatically stronger than conventional Eutectics. Their main advantages being reduced chance of ring/grove welding and reduced piston ring grove wear. If higher piston strength is needed, then generally, a piston manufacturer will ass more copper and nickel to the alloy to gain extra high temperature strength.

All metallurgy aside, it is not so much what material your pistons are made from but their physical design that is will determine ultimate durability and whether they are going to break/seize.

[j cAT]

Originally Posted by speleocaver

Looking up the causes for piston slap and found that it is the primary lack of silicon in the aluminum that makes up the pistons. GM uses 7% the good pistons use 14%.

Quote:
Early in the peace it was common for US forged-piston materials to contain only 7 per cent silicon in their make-up. This led to high temperature expansion rates, making engines sound 'rattly' when started cold. The Germans came to the rescue here with new materials for forged pistons which did away with the undesirable expansion rates, by containing a much more acceptable 14 per cent silicon content. As some top-level German cars have forged pistons standard (BMW V8, V12 ect) it was a requirement that these engines remained smooth and quiet, even when cold - hence the development of better materials. Now, a lot of the aftermarket forged-piston manufactures have caught on and are offering the 'quieter' high silicon content alloy.

With Hypereutectic pistons, the primary reason for having all of this free silicon is to reduce piston ring groove wear. This allows piston designers to move the top compression ring much farther up the side of the piston (where combustion temperatures are much hotter), and run much smaller, thinner piston ring lands (the metal section separating the ring grooves). The reason piston designers want to do this is that it allows a lighter piston to be produced, and also has dramatic results in changing engine emission characteristics. As emission laws become tougher, it will be commonplace to find true Hypereutectic pistons in road engines. It must be added though, that Hypereutectic pistons are not automatically stronger than conventional Eutectics. Their main advantages being reduced chance of ring/grove welding and reduced piston ring grove wear. If higher piston strength is needed, then generally, a piston manufacturer will ass more copper and nickel to the alloy to gain extra high temperature strength.

All metallurgy aside, it is not so much what material your pistons are made from but their physical design that is will determine ultimate durability and whether they are going to break/seize.

piston slap with these 5.3L GM engines in the early 2000 model years is from poor spec control. many pistons were too small..as a result they would slap until heated ...thats if you were lucky..many had larger pistons intalled..It was not a standard exact spec failure ..some had no slap...

silicon amounts used is interesting..so far well over 100,ooomiles no wear issues 11 years this april !