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#110788 - 11/30/04 01:53 AM GM Piston Slap
Craigster Offline


Registered: 08/20/03
Posts: 22
Loc: N.E.
Has anyone found an oil that helps to eliminate the infamous GM piston slap?

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#110789 - 11/30/04 02:14 AM Re: GM Piston Slap
heyjay Offline


Registered: 01/14/04
Posts: 526
Loc: Manitoba Canada
Well, good luck.

I purchased new a 2000 GMC Sierra with that Vortec 5.3. After about a year it started the piston slap thing.

In my case, Mobil 1 15W-50 in summer made the motor silent. There was no MPG penalty I could detect.

However, winters here can dip to -40 or a bit colder. So I ran Mobil 1 0W-30 in winter and the thing knocked a bit cold and gave off an anoying ticking sound hot.

I traded it for a new Toyota Prius and the new car is almost silent, even when the motor runs. My 1984 Ford F-150 with 302 V8 is quieter than the GMC motor ever was.

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#110790 - 11/30/04 02:29 AM Re: GM Piston Slap
Terry Offline


Registered: 05/27/02
Posts: 3845
Loc: Greenville , Texas
Craig, the "assembly lube" used after replacing the pistons and bearing assemblies! [Wink]

I haven't found any specific lube that works in all the oil analysis customers we have complaining of that noise.

Be careful using Viscosity to deaden sound as you can sacrifice lubricity and thats worse. As long as the oil analysis signature and operation is satisfactory I say accept it and enjoy the very efficient engine.

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#110791 - 11/30/04 02:56 AM Re: GM Piston Slap
Chris B. Offline


Registered: 03/16/03
Posts: 2860
Loc: Colorado
Take Terry's advice, it's gold!!! [Wink]

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#110792 - 11/30/04 03:05 AM Re: GM Piston Slap
Rat407 Offline


Registered: 12/13/02
Posts: 705
Loc: North Carolina
So far I'm looking at it this way. Since it has been brought to light, I have not seen much in the way of any problems the piston slap has caused other than an annoying sound. Some on other forums have it and have well over 150k with no problems. I seem to have it now and then. Weird how it comes and goes in my 02 Silverado with the 5.3. I'm currently running Series 3k 5w-30 AMSOIL The last analysis was at 12k on the oil and Terry said it looked good and continued use was ok. So I am. Terry is the man! [Patriot]

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#110793 - 11/30/04 03:07 AM Re: GM Piston Slap
LT4 Vette Offline


Registered: 09/12/04
Posts: 12077
Loc: USA
You might want to check www.pistonslap.com [Cool]

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#110794 - 11/30/04 03:30 AM Re: GM Piston Slap
Al Offline


Registered: 06/08/02
Posts: 13581
Loc: Elizabethtown, Pa
My understanding is that RedLine 10W-30 improved it. This was discusssed a while back-like a year or so. I can tell you that Mobil 1 10W-30 doesn't help.

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#110795 - 11/30/04 03:30 AM Re: GM Piston Slap
Craigster Offline


Registered: 08/20/03
Posts: 22
Loc: N.E.
Thanks for the advise. I will learn to live with it.

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#110796 - 11/30/04 03:44 AM Re: GM Piston Slap
cousincletus Offline


Registered: 09/25/02
Posts: 2513
Loc: Richmond, VA
I had a 1996 Chevy S-10 2.2 OHV that had a slight piston slap and different weight oil didn't make it go away, so I just went back to 10W-30. Noise went away completely once engine warmed up. [Cheers!]

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#110797 - 11/30/04 03:47 AM Re: GM Piston Slap
Yuk Offline


Registered: 06/16/03
Posts: 830
Loc: Edmonton, AB Canada
I'm glad this topic was revisited. I now have evidence to show my wife, proving I'm not an obscene, juvenile, pervert. Every time I talk about piston slap and rod knock she accuses me of making it up, just to be gross.

Now will you please help me convince her that a loose exhaust system is not muff rub! [Eek!]

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#110798 - 11/30/04 03:54 AM Re: GM Piston Slap
cryptokid Offline


Registered: 02/01/03
Posts: 1565
Loc: palm beach
what the heck is a muff rub?

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#110799 - 11/30/04 03:58 AM Re: GM Piston Slap
Yuk Offline


Registered: 06/16/03
Posts: 830
Loc: Edmonton, AB Canada
quote:
what the heck is a muff rub?
You're going to have to figure it out yourself. I don't feel like being censored or expelled from this family friendly site. [Razz]

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#110800 - 11/30/04 04:13 AM Re: GM Piston Slap
Shadohh Offline


Registered: 09/20/04
Posts: 68
Loc: Pottstown, PA
Try a good moly based oil [Smile]

I had some piston slap and switched over to MC 5w30 with a shot of Valvoline syn oil treatment.

I calculate I am aroudn 400-500ppm MOLY, whhihc is like redline oil.

If you wanan play mixoligst. You could mix some Penzzoil and a quart of redline.

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#110801 - 11/30/04 04:22 AM Re: GM Piston Slap
TomJones76 Offline


Registered: 11/06/03
Posts: 1250
Loc: Akron, OH
My car did that this morning until I'd gone a quarter mile. It's supposedly running 5W30. Should I care?

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#110802 - 11/30/04 04:54 AM Re: GM Piston Slap
pitzel Offline


Registered: 09/13/04
Posts: 1353
Loc: Saskatchewan, Canada
The guys at the local engine rebuilding/maching shop are emphatic on the use of synthetic oil in the 3100's from when they are brand new. Their theory is that the engines really aren't very suited to northern climates, and that cold startups are seriously bad for them, causing the development of the piston slap problem.

They also claim that exclusively southern or summer operated engines don't suffer, or only minimally suffer from the problem at all. Any truth to this?

edit: I thought I'd just add, normally these guys aren't very big on synthetic at all -- 'a waste of money', and they're all 'religous' 3000 mile oil changers.

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#110803 - 11/30/04 05:45 AM Re: GM Piston Slap
eddyzima Offline


Registered: 07/30/04
Posts: 166
Loc: western pa
i am going to put on my flame suite and tell you what works for me. castrol syntec 10w30. i know it is not the best oil in the world, but it sure makes my wifes 5.3 tahoe quiet in the mornigs. ALSO, use chevron techtron in the fuel tank every 1k or so. MOBIL 1 IN ALL WEIGHTS AND MIXES MAKES THESE ENGINES NOISEY. i have also had the best resaults with the cheap purolater filters. the 3.99 ones. -ed.

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#110804 - 11/30/04 05:56 AM Re: GM Piston Slap
Ken2 Offline


Registered: 12/02/02
Posts: 6059
Loc: Washington St.
There are two separate causes for the noise GM calls CSK (cold start knock).

One is the piston rattling around in the bore.

The other is carbon built up on the top of the piston and on the head. A warm engine expands enough so the piston and combustion chamber don't knock their carbon together, but a cold engine might have contact. A very good combustion chamber cleaner helps.
http://www.pistonslap.com/tsb/010601028A.htm


Ken

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#110805 - 11/30/04 06:11 AM Re: GM Piston Slap
Shadohh Offline


Registered: 09/20/04
Posts: 68
Loc: Pottstown, PA
And that the idea of getting some moly in the mix. Its a nice additive that will stick to the piston and helps it stay lubed for a cold start.


I am not surprised syntec works. I remember a article that they have an additive in it that helps build a film on the metal surfaces.

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#110806 - 11/30/04 06:35 AM Re: GM Piston Slap
ToyotaNSaturn Offline


Registered: 04/11/03
Posts: 11212
Loc: Spring Hill, TN
If Castrol's Start Up actually works as advertised, would this be worth considering to reduce/eliminate slap?

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#110807 - 11/30/04 07:06 AM Re: GM Piston Slap
ekpolk Offline
The Regenerator


Registered: 04/05/04
Posts: 8881
Loc: Pensacola FL
quote:
Originally posted by eddyzima:
i am going to put on my flame suite and tell you what works for me. castrol syntec 10w30. i know it is not the best oil in the world, but it sure makes my wifes 5.3 tahoe quiet in the mornigs. ALSO, use chevron techtron in the fuel tank every 1k or so. MOBIL 1 IN ALL WEIGHTS AND MIXES MAKES THESE ENGINES NOISEY. i have also had the best resaults with the cheap purolater filters. the 3.99 ones. -ed.

Leave your flame suit in the closet. You've made a precise statement about what works for you. You have not, by way of contrast, claimed or suggested that therefore Syntec 10w-30 is the best thing invented for all cars, cures cancer, prevents nuclear war, etc. . . It's your car and your money and if you've found a way to quiet this befuddling problem in your car, power to you, regardless of whether your solution is Syntec, Redline, or Crisco! [Cheers!]

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#110808 - 11/30/04 09:32 AM Re: GM Piston Slap
Ross Offline


Registered: 09/10/02
Posts: 694
Loc: Bismarck, ND
I have a 2003 Silverado 1500HD with the 6.0

Mine has a slight knock on cold starts, mostly under load and only in the winter. If I let it idle for about 60 seconds, the sound goes away completely.

I am running M1 5w30. I have not tried any other oils yet, cause my engine likes the M1, no useage etc.. I have heard from someone else on this forum that the castrol start up solved his piston knock, but have not tried it myself.

When I bought the truck, I heard that the 2003's had slight modifications to the engines to help muffle the pistion slap (not cure it or prevent it). That's what mine sound like.

This winter I am running FP in every tank to see if it helps. Should know when the temp go below 0!!

[ December 01, 2004, 01:39 AM: Message edited by: Ross ]

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#110809 - 11/30/04 09:23 PM Re: GM Piston Slap
2K2AcuraTL Offline


Registered: 12/22/02
Posts: 375
Loc: Ottawa, Ont CANADA
As for my 98 Pontiac Transsport's piston slap, M1 has been the predominant oil of choice.
This being said:
-I am using GC for the first time in the minivan, and I must say it is performing quite impressively. (as opposed to my experience with GC in the AcuraTL).
-Swepco was the worst for piston slap.
Jean

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#110810 - 11/30/04 09:33 PM Re: GM Piston Slap
twb Offline


Registered: 06/10/02
Posts: 65
Loc: Bergen, NY
I've got a 1998 Silverado with a 350, the last year for the "old" style 350. In the winter I definitely get what people would call piston slap on startup, and it goes away in a minute or so. I'm a little skeptical about it actually being caused by the piston "rattling" around, as I found it's somewhat related to how restrictive the oil filter is. A Mobil 1 filter or a Purolator Plus, lots of rattling. A "regular" Purolator, much less rattling. Why would oil flow change the degree of piston slap?

About Castrol Syntec: I'm a hard core long term Schaeffer's user, but I've tried a number of oils in this engine. Syntec gave me the best UOA of all of them, and that includes Mobil 1. In case you're wondering, I continue to use Schaeffer's because its UOA analyses were very close to the Syntec values, and it costs me a heck of a lot less.

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#110811 - 11/30/04 09:49 PM Re: GM Piston Slap
Vuarra Offline


Registered: 05/15/04
Posts: 89
Loc: Hamilton, ON
quote:
You have not, by way of contrast, claimed or suggested that therefore Syntec 10w-30 is the best thing invented for all cars, cures cancer, prevents nuclear war, etc.
Thanks, ekpolk, but I thought that was either GC or (lubricant deleted due to family values, but contains the letters K and Y)?

[Big Grin]

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#110812 - 11/30/04 10:26 PM Re: GM Piston Slap
haley10 Offline


Registered: 12/28/03
Posts: 2768
Loc: Tn
quote:
Originally posted by eddyzima:
i am going to put on my flame suite and tell you what works for me. castrol syntec 10w30. i know it is not the best oil in the world, but it sure makes my wifes 5.3 tahoe quiet in the mornigs. ALSO, use chevron techtron in the fuel tank every 1k or so. MOBIL 1 IN ALL WEIGHTS AND MIXES MAKES THESE ENGINES NOISEY. i have also had the best resaults with the cheap purolater filters. the 3.99 ones. -ed.

No flame. It worked really well for me in the past. Maybe with the A5/B5 ratings now, it will become more suitable for somewhat extended drains with better TBN retention. It did cold start really well.

The board is overly critical of Syntec 10W-30. The Syntec Blend and GC edge it out in many applications, however. GC can do longer drains and the Blend has good results and TBN retention for the money. It good stuff, though. [Big Grin]

[ December 01, 2004, 02:34 PM: Message edited by: haley10 ]

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#110813 - 11/30/04 10:43 PM Re: GM Piston Slap
Ken2 Offline


Registered: 12/02/02
Posts: 6059
Loc: Washington St.
twb,
"Rattling" is just a figure of speach. Some cold piston knock is very normal in many engines.

For oil filter concerns, I always like to go back to an OEM filter from the dealership. That's what the engine designer's spec'd for that engine. If makes a difference, then an aftermarket filter can be searched for with the same characteristics. The engine makers do not issue specs for oil filters. The aftermarket filter makers reverse engineer the OEM filters. Often they come up with compromises that usually are close enough to matching the OEM filter.

I don't think the oil filter has much if any effect on cold piston slap. There must be some noise in the valvetrain or somewhere else that is adding to the sounds of the engine with the restrictive filters.


Ken

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#110814 - 11/30/04 10:52 PM Re: GM Piston Slap
haley10 Offline


Registered: 12/28/03
Posts: 2768
Loc: Tn
TWB, interesting. What do you notice with the AC Delco or Wix filters, if you have tried them??

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#110815 - 12/01/04 03:35 AM Re: GM Piston Slap
REDDOG Offline


Registered: 09/11/04
Posts: 949
Loc: Hermon, ME
I have noticed that of the oils I have tried so far, Amsoil 5w-30 (ASL) and the Havoline 5w-30 SM/GF-4 I am currently running seem to have quieted the piston slap in my '98 Vortec 4.3 the best. With the Havoline the slap seems to go away in just a few seconds after start up.

The slap seems most prevalent at temps around 20-40 deg F.

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#110816 - 12/01/04 03:53 AM Re: GM Piston Slap
heyjay Offline


Registered: 01/14/04
Posts: 526
Loc: Manitoba Canada
With my 2000 GMC Sierra and Vortec 5.3 V8, I tried the stock AC Delco PF-59 filter and I also tried the Mobil 1 filter, with no difference in oil pressure or noise.

What I found infuriating was that in VERY cold temps (Colder than -20 F) the motor knocked like an old diesel unless I used Mobil 1 0W-30. The problem is, once it warmed up it made ticking noises.

GM can claim whatever they want about their huge problem with "Cold Start Knock" or whatever they want to call it. Piston deposits my a**, why were brand new motors making that noise? They came with deposits from the factory with 20 miles on the odometer??

If you read through www.pistonslap.com you discover that GM had promised a fix, then suddenly changed their minds and told everybody "it's normal, don't worry about it."

Let me guess, if you don't have the noise, there is something wrong with your motor?? HA!

I tried playing with oil viscosity as it was the cheapest - releativly speaking - and easiest thing for me to change.

I figured if the Mobil 1 15W-50 made things much worse, I could always change the oil right away and kiss $45 goodbye. So a person with that nasty noise has little hope of curing it unless they try to experiment.

Or just go to your friendly GM dealer and be told how lucky you are to have a motor that goes, and I quote:

"KNOCK KNOCK KNOCK KNOCK KNOCK KNOCK KNOCK..."

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#110817 - 12/01/04 11:02 AM Re: GM Piston Slap
lewk Offline


Registered: 11/25/04
Posts: 275
Loc: southwest
my 4.3l vortec in my astro van had a minor ticking noise when warm and an annoying oil starved melody when cold. my solution was to use 5w30 like GM recomends but only 4 qts. the final .5 qt for the filter fill I used 15w40. any top off oil was 15w40 too. i used most of the majors, penzoil, exxon, havoline,etc. dont mix brands i.e., use similar brands for different wts. this works fine all year round in so.cal. much of the noise was abated as well. hope this works for some of you too.

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#110818 - 12/01/04 12:22 PM Re: GM Piston Slap
sub_zero Offline


Registered: 03/10/03
Posts: 254
Loc: Calgary AB
It's just a noise isn't it? Can you feel the vibration? If you can it's high energy and is something serious. If not just let it go. Is there any serious wear metals on analysis if you've done one?

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#110819 - 12/01/04 04:34 PM Re: GM Piston Slap
Craigster Offline


Registered: 08/20/03
Posts: 22
Loc: N.E.
So far I have tried GC 0w30, and 5qts of Mobil-1 10w30 with 1 qt of Redline 5w30.
With the GC the knocking was louder and knocked even when engine was warm.
Had oil analysis done with both. Mobil-1 was slightly better.
I am thinking about trying Castrol Start-Up 5w30 next.

Your suggestions are appreciated.

BTW.I have 2002 Chev.Silverado 2500 HD.with the 6.0

[ December 02, 2004, 08:49 AM: Message edited by: Craigster ]

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#110820 - 12/01/04 06:15 PM Re: GM Piston Slap
ToyotaNSaturn Offline


Registered: 04/11/03
Posts: 11212
Loc: Spring Hill, TN
I'm not doubting Terry's findings here, I just find it intruiging that only a few oils quiet things down, but none get rid of it, seemingly, at least.

Has anyone tried any of these oils with any luck? straight Delo? PZ LL?
Delvac 1300?
Any 5w-40 Group III synth, Pennzoil, Havoline, Rotella T, etc?
Supertech 10w-30 "Full" synth?
Castrol 5w-50?

[I dont know]

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#110821 - 12/02/04 08:03 AM Re: GM Piston Slap
Blue99 Offline


Registered: 09/27/03
Posts: 2233
Loc: Wisconsin
per Al
quote:
I can tell you that Mobil 1 10W-30 doesn't help.
per Ed
quote:
MOBIL 1 IN ALL WEIGHTS AND MIXES MAKES THESE ENGINES NOISEY.
I have the same opinion based on running M1 10W-30 last winter in my 99 Silverado with the 5.3L Vortec.

It's my speculation that the cold start knock is louder with a PAO based oil. Similar to the lack of seal swell with PAO, the combustion chamber deposits may actually get harder in the presence of PAO as opposed to a dino oil.

These deposits are located both on the top edge of the piston & ring and on the combustion chamber. As the engine warms up, the deposits soften up & the noise goes away.

A minor film of oil will reach the deposits thru the piston rings and this can aid in keeping the deposits soft & reduce the knocking noise at startup.

My current thoughts are that the natural solvency of GRP I or a dino HDEO, or possibly Esters is what will help reduce the hardness of the deposits and reduce the CSK noise.

BTW, I really like the performance of the 5.3L engine and am willing to put up with the 20-30 seconds of slight knocking during a cold start!

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#110822 - 12/02/04 08:43 AM Re: GM Piston Slap
Terry Offline


Registered: 05/27/02
Posts: 3845
Loc: Greenville , Texas
TNS, Doubt me please, someone besides the wife needs too ! Trust but verify..


Opinions and observations on noises and lubes used.

Specifically M1. M1 is a very "clean" fluid that allow lots of sound transfer because of its formulation.

Sound is not a good measure of a oils capability to lubricate unless you are a highly trained mechanic ( that still has hearing left) and a good stethescope.

Until soluble moly was added to their mix a few years ago ( note amazement in the industry) there was even more sound transfer. [Roll Eyes]

Really great sound insulating lube fluids are not always good lubricants. Fluids that use a PTFE dose insulate sound very well and MAY lubricate a engine very poorly. Heavier vis fluids do the same and may sacrifice lubrication in certain applications.

Generally the lighter the vis of a lube the more you will hear things inside.

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#110823 - 12/01/04 10:39 PM Re: GM Piston Slap
carl97ss Offline


Registered: 05/28/02
Posts: 153
Loc: indpls, in
Tonite I'll be putting in 5w-30 Castrol Start-Up in my "Armored Personnel Carrier on cobblestone roads" sounding modified GM motor tonight. [Roll Eyes] We'll see how it does tomorrow morning. [Big Grin]

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#110824 - 12/01/04 10:45 PM Re: GM Piston Slap
Terry Offline


Registered: 05/27/02
Posts: 3845
Loc: Greenville , Texas
carl, good to hear from you. Did you ever correct the oil consumption issues with the stroker ?

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#110825 - 12/02/04 01:59 AM Re: GM Piston Slap
jafo Offline


Registered: 01/07/04
Posts: 80
Loc: concord,ca
I have a 98 firebird with the ls1,approx. 90k.I recently did a decarb with some seafoam(gm top end cleaner works too)and no more noise at startup.I also followed up with a bottle of redline si1 in the tank.I wasn't trying to get rid of the noise, just doing a decarb as part of regular maintenance.Getting rid of the noise was a definite bonus. [Big Grin]
quote:
Originally posted by Ken2:
There are two separate causes for the noise GM calls CSK (cold start knock).

One is the piston rattling around in the bore.

The other is carbon built up on the top of the piston and on the head. A warm engine expands enough so the piston and combustion chamber don't knock their carbon together, but a cold engine might have contact. A very good combustion chamber cleaner helps.
http://www.pistonslap.com/tsb/010601028A.htm


Ken


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#110826 - 12/02/04 02:12 AM Re: GM Piston Slap
buster Offline


Registered: 11/16/02
Posts: 29080
Loc: NJ
Great post Terry. Always wondered if sound was related to wear. [Cheers!]

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#110827 - 12/02/04 04:02 AM Re: GM Piston Slap
eddyzima Offline


Registered: 07/30/04
Posts: 166
Loc: western pa
quote:
Originally posted by Craigster:
So far I have tried GC 0w30, and 5qts of Mobil-1 10w30 with 1 qt of Redline 5w30.
With the GC the knocking was louder and knocked even when engine was warm.
Had oil analysis done with both. Mobil-1 was slightly better.
I am thinking about trying Castrol Start-Up 5w30 next.

Your suggestions are appreciated.

BTW.I have 2002 Chev.Silverado 2500 HD.with the 6.0

I ALSO HAVE A 2002 2500HD WITH THE 6.0. GREAT TRUCK. BUT THAT 6.0 IS A TICKY CRIDER. [Wink] I ALMOST WORE OUT THE DRAIN PLUG ON THAT THING. THAT IS HOW I CAME ACROSS THE SYNTEC 10W30. I HAVE ALMOST TRIED ALL BRANDS OF OIL AND FILTER. DINO OIL MAKES IT QUIETER ON START UP BUT TICKS WHEN WARM AT IDLE. THE CASROL STARTUP KEEPS IT QIUET AT START UP BUT TICKS WHEN WARM AT IDLE. AND THE SYNTEC BLEND HAS START UP NOISE AND THE TICK AT IDLE. BUT I HAVE RUN 2 CHAGES WITH THE NEW SM SYNTEC 10W30 AND NOCK ON WOOD NO NOISE EVER. I KNOW ITS OVER PRICED FOR THE QUALITY, BUT SURE IS NICE WHEN YOUR 30,000 $ TRUCK IS QUIET. ALSO I HAVE TRIED ALL OIL FILTERS. AND THE CHEAP PUROLARE IS THE QUIETEST. I DON,T KNOW WHY? I HATE TO BABAL ON BUT THIS TRUCK DROVE ME CRAZY. AND I SURE HOPE THIS HELPS YOU. BTW I TALKED TO CASTOL ABOUT STARTUP AND THEY WOULD NOT SAY HOW IT WORKS BUT THEY TOLD ME SYNTEC SM HAS MORE OF THE GOOD STUF. WHAT EVER THAT IS ?

[ December 02, 2004, 08:17 PM: Message edited by: eddyzima ]

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#110828 - 12/02/04 05:45 PM Re: GM Piston Slap
carl97ss Offline


Registered: 05/28/02
Posts: 153
Loc: indpls, in
Hey Terry!! [Cheers!] I never got the consumption problem resolved. My engine builder rebuilt the engine May 2003. He found nothing that made sense for the consumption. It was definately getting by the rings and appears to be doing the same. He went with a Z-06 "type" ring package, measured and rehoned the cylinders but, it has not helped. Static compression is good at 203psi across the board +/-3 psi and each cylinder leaks down about the same at 5-6 psi after 5 minutes. [Confused] During the rebuild we replaced the cam due to excessive wear on 2 of the cam lobes. We replaced all the lifters (Comp Cams "R"- [Mad] )rockers and valve springs. I still use 1 quart per 1000-1500 miles depending on oil weight. Engine dyno'd strong and continues to run great. Over the last 6 weeks been on the road to the tune of 5,000 miles. Running 80 mph+ I averaged 25.2 mpg with 4 tankfulls over 26 mpg! I'm a LC user now. [Smile]

Terry, I have not had an oil analysis done since the last one you did for me. Considering the oil usage, would it be beneficial to have one done w/ the Castrol Start-Up after 5,000 miles? (7 quart capacity) [I dont know]

As for the Castrol Start-Up this morning (28 degrees F), there was a difference in sound vs. Mobil 1 5w30. In my case, I did not expect the piston slap to go away [LOL!] but, it did quiet things down enough for me to notice. [Patriot]

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#110829 - 12/03/04 02:58 AM Re: GM Piston Slap
wtd Offline


Registered: 06/25/02
Posts: 1152
Loc: southwest Mo.
My 98 chevy truck with the 350 has startup knock and it sometimes has a tick when the truck is warmed up. When I used to use Mobil 1, the sounds were a lot louder. With the Chevron Supreme, its not as loud and doesn't seem to last as long. This truck has been making this noise since about 36,000 miles and now I'm at 73,000 miles. It used to bother me but now I just don't care. We will see if it ever becomes an issue.

Wayne

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#110830 - 12/03/04 08:34 AM Re: GM Piston Slap
SKUNKY Offline


Registered: 03/08/04
Posts: 701
Loc: Southland (Arkansas)
I have a '98 GMC 454 bought new 128k at present...piston noise from day one..found this site and started to experiment with the HDEO...PZ LL 15-40 seems to work the best in the summer with a Baldwin filter and 89 octane fuel...also a K&N air filter...this winter I put in M1 Truck & SUV 5-40 with the Baldwin filter and 87 octane ...NO statrup noise what-so -ever...go figure...I'm going to run this oil in the summer and see what it does..additional bonus is an increase in milage from 13 to 15 MPG not pulling anything...if I'm lying, I'm dying

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#110831 - 12/04/04 06:51 PM Re: GM Piston Slap
Craigster Offline


Registered: 08/20/03
Posts: 22
Loc: N.E.
eddyzima-

Glad to here that you found a combo that works!
Thanks for the info.

I will try 3qts of syntech 5w30,and 3 qts of 10w30 for the winter,and then go with straight 10w30 for the summer.

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#110832 - 12/05/04 12:08 AM Re: GM Piston Slap
Blue99 Offline


Registered: 09/27/03
Posts: 2233
Loc: Wisconsin
How about a high moly content oil, such as the new SM/GF-4 Valvoline Maxlife with 300 ppm of moly?

Based on Terry's comments, the moly should help deaden the fluid's ability to transmit noise.

I'm about 2 months away from my next oil change & would like to explore the moly effect for use in my 5.3L.

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#110833 - 12/05/04 06:19 PM Re: GM Piston Slap
ToyotaNSaturn Offline


Registered: 04/11/03
Posts: 11212
Loc: Spring Hill, TN
quote:
Originally posted by Terry:
Specifically M1. M1 is a very "clean" fluid that allow lots of sound transfer because of its formulation.

Sound is not a good measure of a oils capability to lubricate unless you are a highly trained mechanic ( that still has hearing left) and a good stethescope.


Terry, why then if, M1 is a cleaner, less sound deadening product, when I use M1 xW-30 compared to an equivalent dino (say Havoline for example) on my little Saturn, does the NVH come way down? Is it just due to the fact that it's PAO compared to a flat-rate group II?
[I dont know]

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#110834 - 12/06/04 02:19 AM Re: GM Piston Slap
TooManyWheels Offline


Registered: 02/21/03
Posts: 3671
Loc: Houston, Tex
quote:
Has anyone tried any of these oils with any luck? straight Delo? PZ LL?
Delvac 1300?

Delvac 1300 is in my '97 5.7 and not helping.

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#110835 - 12/06/04 03:09 AM Re: GM Piston Slap
Craigster Offline


Registered: 08/20/03
Posts: 22
Loc: N.E.
Castrol syntec did help quiet the piston slap, but it is still there.

I think Terry was right. In most cases no oil is going to eliminate the noise, but it can make a big difference in how loud it is.

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#110836 - 12/07/04 05:25 PM Re: GM Piston Slap
carl97ss Offline


Registered: 05/28/02
Posts: 153
Loc: indpls, in
I have to agree with you Craigster. [Cheers!]

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