POLL: Synthetic vs Dyno oil to quiet Piston Slap

[Suprteck]

I am some what new to the group and hope I am doing this correctly.

I own a 2002 Silverado Z71 5.3 L. I have the piston slap/knock noise.
I switched over to Mobil 1 Synthetic 5w30 at the 9000 mile mark and now have aprox 36000 miles on the truck.

I have searched the threads looking for information on anything that might help quiet the noise in any way. I picked up some information on the web also , some say if you use Mobil 1 Synthetic 10w40 it helps a lot.
I talked with many dealerships and get mixed opinions,some say use Pro Long, some say Mobil 1, some say Engine Restore, and some say Dyno oil is better then all those but all say that using the 10w40 instead of the 5w30 will NOT void any warranty that the only neg. is I will notice a slight gas mil. diff.
But the funny thing is when I ask them if they have personaly used these products or know someone that has and heard a differance they say NO. Just that they heard they work. Except one who uses Mobil 1 5w30 and says he THINKS it makes a diff.

Any way considering all the people here I figured this would be a wealth of information.

So has any one tried different oils and what type and brand seems to help the most.

Or has anyone found any thing at all to help quiet the embarssing sound.

Thanx for all comments

[Jimmiz71]

I have 80k on my truck and use Valvoline High Mileage 5w30 with one quart of Rinslone additive with every change every 2500 miles, the Piston slap in my truck is very faint but more noticable when the engine is cold then it dissapears once the oil circulates. I thought about switching to synthetic but everyones opinions were mixed about it, I change my oil so frequently that it really wouldnt make that much of a difference.
-Jimmy

[Puffnstuff]

I've heard different reasons for the noise including a build up of carbon on the pistons. I had a 99 with the 5.3 and twice it made that knocking sound when it had very low miles on it using the factory oil. On my first change I went to mobil 1 5w-30 with the acdelco pf59 filter and never heard that sound again. I had the truck until it had 30k on it and it ran fine with the mobil 1 in it. I did have another problem that a superchips tuner took care of but no more knocking sounds. Just remember that your mileage may vary and what works for one person might not work for you. Synthetic oil has a high detergent content so it will clean up your engine.

[jerrylittle]

Originally Posted by Suprteck

I am some what new to the group and hope I am doing this correctly.

I own a 2002 Silverado Z71 5.3 L. I have the piston slap/knock noise.
I switched over to Mobil 1 Synthetic 5w30 at the 9000 mile mark and now have aprox 36000 miles on the truck.

I have searched the threads looking for information on anything that might help quiet the noise in any way. I picked up some information on the web also , some say if you use Mobil 1 Synthetic 10w40 it helps a lot.
I talked with many dealerships and get mixed opinions,some say use Pro Long, some say Mobil 1, some say Engine Restore, and some say Dyno oil is better then all those but all say that using the 10w40 instead of the 5w30 will NOT void any warranty that the only neg. is I will notice a slight gas mil. diff.
But the funny thing is when I ask them if they have personaly used these products or know someone that has and heard a differance they say NO. Just that they heard they work. Except one who uses Mobil 1 5w30 and says he THINKS it makes a diff.

Any way considering all the people here I figured this would be a wealth of information.

So has any one tried different oils and what type and brand seems to help the most.

Or has anyone found any thing at all to help quiet the embarssing sound.

Thanx for all comments

I have a 98 with a new motor because the dealer burnt up the original. Right from day one the new motor out of the crate made a knocking noise sounds like a rod. I have used moble one in it from day one also. I used 5-30 and now 15-50 I now have 25,000 on the motor and it is still there.

[Faze2183]

i have been running royal purple 10w30 for the winter time, and ive never had any kinda problems running royal purple..... my milage has gone up, it doesnt break down as fast as most oils do, u will maybe notice some hp diffrences, over all greatest oil to use, and now that its summer time im usin 20w50, btw the oil is purple just in case no one knew that already heh

btw: i change my oil every 5k miles and use fram x2 oil filter and i dont think i could ever use any other oil im very happy and guess what its true Synthetic......

try royal purple suprteck, you will not go wrong and u can pick up that stuff at napa auto parts, ill recomond buyin a case cuz its cheaper

[jerrylittle]

Originally Posted by Faze2183

i have been running royal purple 10w30 for the winter time, and ive never had any kinda problems running royal purple..... my milage has gone up, it doesnt break down as fast as most oils do, u will maybe notice some hp diffrences, over all greatest oil to use, and now that its summer time im usin 20w50, btw the oil is purple just in case no one knew that already heh

btw: i change my oil every 5k miles and use fram x2 oil filter and i dont think i could ever use any other oil im very happy and guess what its true Synthetic......

try royal purple suprteck, you will not go wrong and u can pick up that stuff at napa auto parts, ill recomond buyin a case cuz its cheaper

IS this royal blue synthetic? If so who makes it?

[Faze2183]

yes it is synthetic its almost pure synthetic, its made by www.royalpurple.com check them out u will like them alot

[HDChvyTrk]

I would suggest synthetic oil but i do not believe it will help your noise. The noise in the 4.8, 5.3, and some 6.0 engines is the smae noise the firebirds and camaro's had when the 5.7 LS1 was new and it is PISTON SLAP. All these motors use next generation hypereutic pistons.
What Hypereutic is in a nut shell: A piston is a round piece of aluminium with a large steal pin ththrought the center of it. A piston also has a SKIRT which is designes to help offset torsional stress applied by the rod as the piston travels upand down the cylinder. When the round piston heats up durring start up, it expands. It expands different amounts because the area were the pin is is much thicker thus creating a slightly ovalized piston. Most engines use a bore that is slightly larger then the piston to accomodate this mishape.
A while ago some one got he great idea to make a piston that was an oval cold and would become more round as it heated. Sounds great in theory and it works fine in the aftermarket but with production tolerances in place for assembly you end up with pistons that have a little more play in the skirt area then they should. This then dissapears when the engine has warmed up.
No oil will make this sound go wawy. Heavier oil will muffle it. Lighter oil will shorten the time you hear it as it travels through the motor faster.

[jerrylittle]

Originally Posted by HDChvyTrk

I would suggest synthetic oil but i do not believe it will help your noise. The noise in the 4.8, 5.3, and some 6.0 engines is the smae noise the firebirds and camaro's had when the 5.7 LS1 was new and it is PISTON SLAP. All these motors use next generation hypereutic pistons.
What Hypereutic is in a nut shell: A piston is a round piece of aluminium with a large steal pin ththrought the center of it. A piston also has a SKIRT which is designes to help offset torsional stress applied by the rod as the piston travels upand down the cylinder. When the round piston heats up durring start up, it expands. It expands different amounts because the area were the pin is is much thicker thus creating a slightly ovalized piston. Most engines use a bore that is slightly larger then the piston to accomodate this mishape.
A while ago some one got he great idea to make a piston that was an oval cold and would become more round as it heated. Sounds great in theory and it works fine in the aftermarket but with production tolerances in place for assembly you end up with pistons that have a little more play in the skirt area then they should. This then dissapears when the engine has warmed up.
No oil will make this sound go wawy. Heavier oil will muffle it. Lighter oil will shorten the time you hear it as it travels through the motor faster.

hmmmm I would have to bag your pardon. I have a brand new 5.7 LSI 98 and it does it when just started and even after hours of running it. I know someone who has a 5.3 same thing does not matter if it is cold or hot. I am told there is nothing to worry about it will still last just as long and not come apart. My motor was a crate motor from chevy not a reman from chevy. Still under warranty.

[HDChvyTrk]

The more slop there is between the piston and cylinder wall the more pronounced the noise will be and it may not go completly away but I bet it is louder when it is cold then when it is warmed up??

[jerrylittle]

Originally Posted by HDChvyTrk

The more slop there is between the piston and cylinder wall the more pronounced the noise will be and it may not go completly away but I bet it is louder when it is cold then when it is warmed up??

Hard to say it seems to change a bit sometimes it seems so when it is cold sometimes it seems so when it is warm? I probably wont get much life out of it huh? I used synthetic moble 1 from day one I gave to the dealer when they installed the motor.

[HDChvyTrk]

I am not sure about that, I know two people who have 90k plus miles and, minus the noises, there trucks still run fine? kind of funny that these motors have these noises but seem to be some of the best performing engines out their. Just a little disconcerting to start your 30k-35k dollar vehicle and here theose obnocious sounds huh?

[Dale fan]

I know when I switched to Mobil 1 from dino in my 6.0 the slap is louder but mine has always went away within a minute. Sounds like lifter's ticking.

[Suprteck]

Thanks for the responses so far.

I tried the 10w40 thing out, I went and got the AC delco filter from the dealership close by and asked them about the Engine Restorer idea. They said that some people have tried it but they would highly recomend NOT using it or any additive. They said to try using Valvoline Max Life 10w40 dino, so i went with that.

After i changed the oil and filter i noticed the knock was now louder and more pronounced and never went away no matter how hot I got the motor. But now it sounded like one piston knocking instead of multiple. Then came the driving test, there are some back road long under passes around here that you can realy get a good listen to what your truck sounds like outside the cab as you are driving through them, as i drove and after transmission shifts into second gear i would release off the accelerator and get a louder more noticable diesel sound like valves clattering but it was the piston slap. So with using a thicker oil the piston slap in my vehicle became worse.

At least with Mobil 1 5w30 synthetic by the time i get to the store and if i leave the truck on to listen there is no knocking that is noticable at idle until i turn it off and restart it, the diesel sound is still there while driving but is slightly quieter..

I love the looks of my truck and to date 2 yrs old and 36000 miles i have not had any problems worth noting but this constant knocking piston slap diesel sound is just killing me. I HATE THIS MOTOR. TRUELY HATE IT.

SIDE NOTE

I talked with a real reputable well known auto machine shop out here in CA. They build custom motors for pro racers.
and could get new pistons and cylinders worked on the whole works for about 3000.00, he said i should think about it and that its cheaper then buying a new truck but is it a good idea, I think it would just open up a pandoras box.

thanks again for the comments so far, i am very interested in hearing more.


MY TRUCK:
02 Siverado Z71, 5.3L
4" Rancho Suspension Lift
Nitto LT305's on Weld Racing Rims
Flowmaster 70 series Dual Cat Back

[jerrylittle]

Originally Posted by Suprteck

Thanks for the responses so far.

I tried the 10w40 thing out, I went and got the AC delco filter from the dealership close by and asked them about the Engine Restorer idea. They said that some people have tried it but they would highly recomend NOT using it or any additive. They said to try using Valvoline Max Life 10w40 dino, so i went with that.

After i changed the oil and filter i noticed the knock was now louder and more pronounced and never went away no matter how hot I got the motor. But now it sounded like one piston knocking instead of multiple. Then came the driving test, there are some back road long under passes around here that you can realy get a good listen to what your truck sounds like outside the cab as you are driving through them, as i drove and after transmission shifts into second gear i would release off the accelerator and get a louder more noticable diesel sound like valves clattering but it was the piston slap. So with using a thicker oil the piston slap in my vehicle became worse.

At least with Mobil 1 5w30 synthetic by the time i get to the store and if i leave the truck on to listen there is no knocking that is noticable at idle until i turn it off and restart it, the diesel sound is still there while driving but is slightly quieter..

I love the looks of my truck and to date 2 yrs old and 36000 miles i have not had any problems worth noting but this constant knocking piston slap diesel sound is just killing me. I HATE THIS MOTOR. TRUELY HATE IT.

SIDE NOTE

I talked with a real reputable well known auto machine shop out here in CA. They build custom motors for pro racers.
and could get new pistons and cylinders worked on the whole works for about 3000.00, he said i should think about it and that its cheaper then buying a new truck but is it a good idea, I think it would just open up a pandoras box.

thanks again for the comments so far, i am very interested in hearing more.


MY TRUCK:
02 Siverado Z71, 5.3L
4" Rancho Suspension Lift
Nitto LT305's on Weld Racing Rims
Flowmaster 70 series Dual Cat Back

Wow! sounds a lot like mine I told the chevy dealer and one said that many of these trucks do it. He said it will not come apart on you don't worry. When mine was new the whole valve train would make noise when it got hot almost like a diesel. Since it broke in that went away. Just noise that knocking that sounds like it is coming from the oil pan. huh? O'well I guess. Still under warranty for another 25k.