Piston slap…DAMN IT!!
Question:
I guess that says it all, if any of you guys are looking for the real deal on this problem it;s worth your time to check out this link, Good Job Sewmun
– Hide quoted text — Show quoted text -> You need to do a search or go here > http://www.pistonslap.com/
Response:
"Gary Glaenzer" wrote > seen many of the 4.2’s yet ? > what’s your impression? good ? bad ? ugly ?
So far so good. I replaced a complete engine assembly a few weeks ago…(you can’t get very many internal parts yet)…customer had taken the vehicle to a quickie lube….their filter was defective and leaked all the oil out. This was a 2003 model which no longer has an oil level sensor in the pan like the 2002 models. (why they changed this is beyond me…I wouldn’t have had to put a motor in it if the engine had a level sensor) Other then this motor, we haven’t done any work on them. Thank goodness nobody is bitching about how noisy they are cold (grin). The engine is very well built…the head and valve train looks similar in some respects to the Northstar engine. The variable timing exhaust shaft is kinda cool, I pulled the actuator valve out and had a look, it really is nothing more then a fancy spool valve that controls oil pressure to the cam retard actuator through a hollow portion of the cam. The front diff is bolted to the pan….comes off real easy when the engine is out of the vehicle, but what’s it going to be like when the engine is in the vehicle? From what I can see, you will have to pull the engine in order to do any work on the actual diff itself. The front axle disconnect is on the other side of the pan, and it simply unbolts from the pan and slides off the shaft that goes thru the pan. Anybody want a 4.2 engine with a bottom end knock? The complete engine is sitting between my bench and my toolbox. Since the customer had to pay for the engine (10k just for the motor) it didn’t have to be destroyed. I think I might see if the local tech school wants it. I doubt there are many/any of these engines kicking around. By the way, the engine still has 6 coil packs and the fuel rail and 6 injectors. Plus all the sensors on the engine….no wonder it costs so much. Ian
Response:
I just went to that site. After looking at the pictures I only see a bad intake valve stem seal causing a little carbon build up. The "scoring" he is trying to show is actually the Teflon (black coating around the piston pins) scuffing onto the walls of the cylinder. The machine marks are clearly visible and if there was actually scoring it would be seen as damage to the factory hone pattern. If you look at the close up of the "bad" cylinder head you can see that it also hints at a lack of routine maintenance with the varnish on the intake side. Steve W.
> You need to do a search or go here > http://www.pistonslap.com/
—–= Posted via Newsfeeds.Com, Uncensored Usenet News =—– http://www.newsfeeds.com – The #1 Newsgroup Service in the World! —–== Over 80,000 Newsgroups – 16 Different Servers! =—–
Response:
"Steve W." wrote > I just went to that site. After looking at the pictures I only see a bad > intake valve stem seal causing a little carbon build up. The "scoring" he is > trying to show is actually the Teflon (black coating around the piston pins) > scuffing onto the walls of the cylinder. The machine marks are clearly > visible and if there was actually scoring it would be seen as damage to the > factory hone pattern. If you look at the close up of the "bad" cylinder head > you can see that it also hints at a lack of routine maintenance with the > varnish on the intake side.
I just went there too. The site account has been suspended. I remember going there a few months back and thinking that if what he was showing in the pictures was what he "imagined" was piston slap, he needs to come over to our shop and I’ll show him what a set of really scored pistons looks like. Ian
Response:
Hello Chevy fans. Just lurking to see what Chevys is up to and can tell you I have the same problem with my 2000 Expedition. Mine started happening around 15K miles and once the engine warms up, it disappears. Ford has told me the same thing "this is normal" Well, they can keep their normal trucks. Besides Chevy and Ford, my local dealer, who also sells Toyota’s says they have an issue with this on the Tundra. Good luck. Ken
– Hide quoted text — Show quoted text -> Well… apparently the cold engine knock that started in my 2000 GMC Sierra > SLE 4X4 just 2-3 months ago at about -18 C is Pistion slap. Or so the dealer > told me, just before my warranty ran out. They said it’s good you told us > about it. It’s normal. It’s on your vehicle record in case it gets worse. GM > engineering is aware of the problem and doesn’t yet have a fix. Anyway I > never did hear the noise before, until then. Now today at +10C after letting > my truck sit for 4 hours then starting. Knock, Knock…..guess what’ there? > Same noise! > So, is pistion slap dependant on temperature? Is it really because it > gets colder outside, pistion shrinkage..then when it warms it > expands….blah blah blah or is this just hype? If this is normal, why is it > just happening now, why not in the past three years? Anyone with ideas? > Damn….I’m starting to hate GM. Never thought I’d say that. > Glenn, > Proud piston slapper owner.
Response:
> Hello Chevy fans. > Just lurking to see what Chevys is up to and can tell you I have the same > problem with my 2000 Expedition.
This phenomenon is common with more and more vehicles these days as manufacturers seem to be going with shorter piston skirts and other design features to minimize reciprocating mass and maximize power and fuel efficiency. My Honda Civic developed this at 60,000 miles (despite haveing seen Mobil 1 during 90% of its life up to that point) and my brand new ‘03 Nissan Sentra Spec-V has the same noise for the first two minutes in cold weather. The piston is a little loose in the cylinder at cold temps due to shrinkage and it essentially rattles in the bore. The colder the temp, the louder the noise and the longer it takes to go away. So, what can you do about it? Well, I have found that oils with a heavy dose of molybdenum minimize the problem … most notably Red Line oil: www.redlineoil.com Switching to Red Line 5W30 during the winter made 80-90% of the awful knocking noise go away. I wasn’t expecting this to happen … but I was extremely impressed when it did. >;^D Schaeffer, Pennzoil and some of the newer 5W20 oils have a fair amount of molybdenum. These are cheaper alternatives to Red Line but I can’t be sure they will have the same dramatic effect as the $8 per quart Red Line synthetic. — Bror Jace
Response:
Bror, Thanks for the reply. I think I will try and it see. What else do I have to lose? Ken
– Hide quoted text — Show quoted text -> Hello Chevy fans. > Just lurking to see what Chevys is up to and can tell you I have the same > problem with my 2000 Expedition. > This phenomenon is common with more and more vehicles these days as > manufacturers seem to be going with shorter piston skirts and other > design features to minimize reciprocating mass and maximize power and > fuel efficiency. My Honda Civic developed this at 60,000 miles > (despite haveing seen Mobil 1 during 90% of its life up to that point) > and my brand new ‘03 Nissan Sentra Spec-V has the same noise for the > first two minutes in cold weather. > The piston is a little loose in the cylinder at cold temps due to > shrinkage and it essentially rattles in the bore. The colder the temp, > the louder the noise and the longer it takes to go away. > So, what can you do about it? Well, I have found that oils with a > heavy dose of molybdenum minimize the problem … most notably Red > Line oil: > www.redlineoil.com > Switching to Red Line 5W30 during the winter made 80-90% of the awful > knocking noise go away. I wasn’t expecting this to happen … but I > was extremely impressed when it did. >;^D > Schaeffer, Pennzoil and some of the newer 5W20 oils have a fair amount > of molybdenum. These are cheaper alternatives to Red Line but I can’t > be sure they will have the same dramatic effect as the $8 per quart > Red Line synthetic. > — Bror Jace
Response:
WRT piston knocking, and using oil filters with a check valve might prevent the problem as it stops oil from draining out of filter when motor is off. YMMV. -G
Response:
Hello Grumbler, Tried that as the dealer suggested but it didn’t help. RATS!
– Hide quoted text — Show quoted text -> WRT piston knocking, and using oil filters with > a check valve might prevent the problem as it > stops oil from draining out of filter when motor > is off. YMMV. > -G
Response:
> Tried that as the dealer suggested but it didn’t help.
You could consider getting Shell Rotella T 15W40 from Wal-Mart along with can of Restore for 8-cyl and see if it helps. Am happy with that combo in my ‘84 GMC, and it feels/runs smoother now. Again, YMMV, as I’m not an engineer nor do I play one on teevee. =8^) BTW, also poured a pint of SeaFoam in tank. See site at www.seafoamsales.com — got it at Napa. -G
Response:
Grumbler, Thanks. I’ll give it a shot. Once I get it back from the dealer. You see, I now have a transmission problem, the dealer thinks. We heard a sound from the tranny area and now they’re going to do their parts replacement procedure. They *think* it’s the torque converter and or the trans pump. I had the trans serviced at 35K. Maybe, I should’ve left it alone 
Oh, well. That’s a shame because I really liked the vehicle. I’m going to the Chevrolet and GMC dealers next week to look at the Yukon and Tahoe. Ken
– Hide quoted text — Show quoted text -> Tried that as the dealer suggested but it didn’t help. > You could consider getting Shell Rotella T 15W40 > from Wal-Mart along with can of Restore for 8-cyl > and see if it helps. > Am happy with that combo in my ‘84 GMC, and it > feels/runs smoother now. Again, YMMV, as I’m > not an engineer nor do I play one on teevee. =8^) > BTW, also poured a pint of SeaFoam in tank. See > site at www.seafoamsales.com — got it at Napa. > -G
Response:
"Da Newf" wrote > Well… apparently the cold engine knock that started in my 2000 GMC Sierra > SLE 4X4 just 2-3 months ago at about -18 C is Pistion slap. Or so the dealer > told me, just before my warranty ran out. They said it’s good you told us > about it. It’s normal. It’s on your vehicle record in case it gets worse. GM > engineering is aware of the problem and doesn’t yet have a fix. Anyway I > never did hear the noise before, until then. Now today at +10C after letting > my truck sit for 4 hours then starting. Knock, Knock…..guess what’
there? Oh Gm engineering has a fix all right. They are not going to fix anything unless the noise meets a certain criteria. When it meets that criteria, they will replace pistons in the 4.8, 5.3, and in the case of the 6.0….pistons and crank and possibly a new engine. > So, is pistion slap dependant on temperature? Is it really because it > gets colder outside, pistion shrinkage..then when it warms it > expands….blah blah blah or is this just hype? If this is normal, why is it > just happening now, why not in the past three years? Anyone with ideas?
You usually notice the noise when you first start the vehicle up….doesn’t really matter what the temp is outside. The colder it is initially, the longer the noise will be there. If the noise is gone within a few minutes, it’s totally normal. If it goes away by the time the engine has completely warmed up…GM won’t do anything about it. For a while, we had these trucks coming in every day for us to listen to the engine noises. We finally educated our service advisors that the noise is normal and GM isn’t going to fix it anyway, so there is no use wasting our time listening to engine noises that are normal. Ian
Response:
it’s not normal it is related to temperature and damn it’s cold where you live do you have a "block heater" installed on the vehical? what viscosity of oil are you running? does it have the "slap"….after running for a while? when was the last time you changed the "antifreeze" in the vehical, and how much did you put in it (ratio to water) ?? how many miles on the last oil change? how long since the last tune-up? has ANY service work been done to vehical just prior to the piston does it make the knoise under moderate to heavy accelleration , from a stop?? IF ITS COVERED UNDER WARRANY…..WHY DON’T THEY FIX IT????? suggestion….. BEFORE THE WARRANTY RUNS OUT…….carry it back and complain again….get it documented. ….and get it documented. do this at least 4 or 5 times BEFORE the warranty runs out. if you bought the vehical new, and can verify that you followed the documented to FORCE THEM to do it. Without the doccumentation, its your word against theirs.
Response:
Thanks Doc., So what I originally thought was right. I guess I have to live with it eh? Damn! paying so much for a new vehicle and then this. I thought I was lucky when I heard about this prob and I didn’t have it, then about 2-3 months ago bam!!! There it is. It only lasts about 30-60 sec max when really cold, maybe 30 when outside temp is warmer. When outside temp is warmer, the knock is not near as loud and much shorter. To reply to the other reply-posts here… Yes I bought the Vehicle new in march 2000, there’s only 51000 km (30000 miles) on it now. It’s a 4.8L V8. All service has been done by the dealer on time. Yeah everythings ok. Coolant etc. Temp????That’s not cold!!! It get’s worse in other parts of the country!! This is Canada!! The temp ranges from +40 to -40 or more depending locale. The truck works great (other than the obvious) and I love it!! Sometimes I wish I was back home and still driving the ol’ 92 305 Way more reliable. Thanks guys for the responses, Glenn
– Hide quoted text — Show quoted text -> Well… apparently the cold engine knock that started in my 2000 GMC > Sierra > SLE 4X4 just 2-3 months ago at about -18 C is Pistion slap. Or so the > dealer > told me, just before my warranty ran out. They said it’s good you told us > about it. It’s normal. It’s on your vehicle record in case it gets worse. > GM > engineering is aware of the problem and doesn’t yet have a fix. Anyway I > never did hear the noise before, until then. Now today at +10C after > letting > my truck sit for 4 hours then starting. Knock, Knock…..guess what’ > there? > Same noise! > So, is pistion slap dependant on temperature? Is it really because it > gets colder outside, pistion shrinkage..then when it warms it > expands….blah blah blah or is this just hype? If this is normal, why is > it > just happening now, why not in the past three years? Anyone with ideas? > Damn….I’m starting to hate GM. Never thought I’d say that. > Glenn, > Proud piston slapper owner. > Glenn, > Caused by excessive piston-to-bore clearance when cold. It IS temp > dependant. GM says it’s normal, doesn’t seem to cause any longevity issues, > just annoying as shit. Only started within the past three years with the > Gen III smallblock motors (4.8, 5.3, 6.0, 8.0>. Never an issue with Gen > II’s <305, 350, 454>. > Doc
Response:
You need to do a search or go here http://www.pistonslap.com/
Response:
> it’s not normal
Yes it is….especially in his case where the noise only lasts a few minutes. > IF ITS COVERED UNDER WARRANY…..WHY DON’T THEY FIX IT?????
Because it’s part of the normal operation of the engine. Believe it or not….just because engine’s "used to" not exhibit what they term piston slap, doesn’t mean it’s not normal today. It has a lot to do with the design of the piston. > if you bought the vehical new, and can verify that you followed the
> documented to FORCE THEM to do it. Without the doccumentation, its your > word against theirs.
Why does the dealership have to fix something that is "normal"? Many supposed problems with vehicles are quite normal and what needs to be done is to educate the customer. Frankly, I’m not particularly thrilled about the noise that newer engines make when cold, but a large percentage of GM engines make this noise. You ought to hear the 4.2 in line 6 when it starts up cold. You’d swear it was a diesel. If it was an abnormal noise…the dealership would probably fix it whether you had outstanding documentation or not. Hell, I just installed a brand new 3.1 engine in a Malibu because it had scored pistons…. way over warranty, but the customer was such a pain in the ass that the service manager just wanted him "gone". A set of pistons would have fixed the problem, but we’d never have heard the end of it. As it was, the new engine has some piston slap noise right out of the crate. Oh well, GM and their innovative engineering….??? Ian
Response:
> cold, but a large percentage of GM engines make this noise. You > ought to hear the 4.2 in line 6 when it starts up cold. You’d swear > it was a diesel.
seen many of the 4.2’s yet ? what’s your impression? good ? bad ? ugly ?
Response:
fixed theres some good advice
Response:
Well… apparently the cold engine knock that started in my 2000 GMC Sierra SLE 4X4 just 2-3 months ago at about -18 C is Pistion slap. Or so the dealer told me, just before my warranty ran out. They said it’s good you told us about it. It’s normal. It’s on your vehicle record in case it gets worse. GM engineering is aware of the problem and doesn’t yet have a fix. Anyway I never did hear the noise before, until then. Now today at +10C after letting my truck sit for 4 hours then starting. Knock, Knock…..guess what’ there? Same noise! So, is pistion slap dependant on temperature? Is it really because it gets colder outside, pistion shrinkage..then when it warms it expands….blah blah blah or is this just hype? If this is normal, why is it just happening now, why not in the past three years? Anyone with ideas? Damn….I’m starting to hate GM. Never thought I’d say that. Glenn, Proud piston slapper owner.
Response:
– Hide quoted text — Show quoted text -> Well… apparently the cold engine knock that started in my 2000 GMC Sierra > SLE 4X4 just 2-3 months ago at about -18 C is Pistion slap. Or so the dealer > told me, just before my warranty ran out. They said it’s good you told us > about it. It’s normal. It’s on your vehicle record in case it gets worse. GM > engineering is aware of the problem and doesn’t yet have a fix. Anyway I > never did hear the noise before, until then. Now today at +10C after letting > my truck sit for 4 hours then starting. Knock, Knock…..guess what’ there? > Same noise! > So, is pistion slap dependant on temperature? Is it really because it > gets colder outside, pistion shrinkage..then when it warms it > expands….blah blah blah or is this just hype? If this is normal, why is it > just happening now, why not in the past three years? Anyone with ideas? > Damn….I’m starting to hate GM. Never thought I’d say that. > Glenn, > Proud piston slapper owner.
Glenn, Caused by excessive piston-to-bore clearance when cold. It IS temp dependant. GM says it’s normal, doesn’t seem to cause any longevity issues, just annoying as shit. Only started within the past three years with the Gen III smallblock motors (4.8, 5.3, 6.0, 8.0>. Never an issue with Gen II’s <305, 350, 454>. Doc
