GM 5.3L Piston Slap issue

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Jan 30, 2006
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Ohio
I have a 2002 Suburban with 70,000 on the clock which has slapped from day 1 and runs terrific and quiet as a mouse and no leaks anywhere. I have been using Penzoil 5w30 & Fram or Delco filter since new with first OCI at 100 miles then every 3000 religiously. I have tried valvoline 5w30 dino as well and both seem to slap for the first minute of warm up but both get good oil pressure and I never have to add any except when I drive to Florida and back then I use 1/2 quart in 3000 miles. Does anybody out there know of an oil that quiets the slap? I have been told that this is caused by short piston skirts and has nothing to do with engine longevity. Does anybody know if this is true? It slaps in the Winter AND in Summer heat as well. Thanks for reading this. KB
 
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I have spent the past 5 months I have owned my 3100 cutlass, and hundreds of dollars trying to answer this same question. I have 5 gallon buckets full of used oil with 1000 miles or less in my shed from my journey to help the case of the slaps. Mine slaps until its 150F. and then I hear a continued knock that I haven't decided is slap or a lifter. I have found that synthetics in my case, make it louder. I have used amsoil, Mobil 1, castrol syntec, castrol gtx, shell, in many different viscosities. My next move will be to catrol gtx startup or syntec blend. Thicker seems to reduce it. It your truck is to use 5w30 or 10w30, go with 10w30, its thicker at startup, which seens to cushion the pistons better, plus reduced oil burning. My advice would be to take the move I am going to in my next change, if you can find it, try castrol gtx startup 10w30 for 3000 miles and see if you see a reduction in your slap.
 
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I'm a fan of the 5.3L engine in the Chevrolet & GMC pickup trucks. Plenty of power & a smooth running engine. [Smile] I sold my 99 Silverado with 123K on the odometer and currently have a 2001 GMC Sierra 4x4 with only 52K miles. The 99 Silverado would briefly slap for a 10 second period, about 30 seconds after it started. Or it would slap on initial acceleration if not warmed up for 90 seconds before putting it in gear. In my experience, a heavier viscosity will help minimize the slap, as the thicker oil during a cold start probably does a better job of sticking to the cylinder walls and aiding any tolerance issues in the rod bearings. Here's a list of oils that helped minimize the slap/CSK noise. Pennzoil or Havoline 10W-30 Hi Mileage - 12 cSt Havoline 10W-30 & Delo 15W-40 mix - 12 cSt (4 qts 10W-30 to 2 qts 15W-40) Pennzoil 10W-40 - 13 cSt Note - the Pennz 10W-40 is a lighter weight 10W-40 and I suspect that it shears rather quickly into the 12 cSt range. Another thing to keep in mind, and I'm not the only member to make this observation, cold start-up noise tends to increase when parked on an incline with the vehicle pointed uphill, - seems to be associated with the oil level in the crankcase & the oil pump pickup.
 
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has anyone ever slapped a chevy dealer service manager over this? i have a metal gauntlet i will mail to them so they dont hurt their hand.
 
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I had the slap on my last 5.3 and what helped it was to get a GM "Decarbonization". It did work and helped it for quite a while.
 
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seems like the engineers deserve the slep more than the service manager [Smile] or maybe the accountants
 

KBFXDLI

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Thanks guys! So what I am hearing is that I should try Penzoil 10w40 and slap the GM service mgr. with a metal gauntlet......hmmmm....well OK...I'll try it and report back! Thanks much! KB PS..think the truck's going to like it but not certain about the service guy.....
 

KBFXDLI

Thread starter
Joined
Jan 30, 2006
Messages
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Ohio
quote:
Originally posted by HACCOFFICER: I have spent the past 5 months I have owned my 3100 cutlass, and hundreds of dollars trying to answer this same question. I have 5 gallon buckets full of used oil with 1000 miles or less in my shed from my journey to help the case of the slaps. Mine slaps until its 150F. and then I hear a continued knock that I haven't decided is slap or a lifter. I have found that synthetics in my case, make it louder. I have used amsoil, Mobil 1, castrol syntec, castrol gtx, shell, in many different viscosities. My next move will be to catrol gtx startup or syntec blend. Thicker seems to reduce it. It your truck is to use 5w30 or 10w30, go with 10w30, its thicker at startup, which seens to cushion the pistons better, plus reduced oil burning. My advice would be to take the move I am going to in my next change, if you can find it, try castrol gtx startup 10w30 for 3000 miles and see if you see a reduction in your slap.
I wouold be using those buckets of oil if I were you! Why waste the money already spent? It's like trying to talk sense to my 16 year old daughter......hmmm... maybe she is a GM spy?
 
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Dec 18, 2005
Messages
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Pennsylvania
quote:
Originally posted by KBFXDLI:
quote:
Originally posted by HACCOFFICER: I have spent the past 5 months I have owned my 3100 cutlass, and hundreds of dollars trying to answer this same question. I have 5 gallon buckets full of used oil with 1000 miles or less in my shed from my journey to help the case of the slaps. Mine slaps until its 150F. and then I hear a continued knock that I haven't decided is slap or a lifter. I have found that synthetics in my case, make it louder. I have used amsoil, Mobil 1, castrol syntec, castrol gtx, shell, in many different viscosities. My next move will be to catrol gtx startup or syntec blend. Thicker seems to reduce it. It your truck is to use 5w30 or 10w30, go with 10w30, its thicker at startup, which seens to cushion the pistons better, plus reduced oil burning. My advice would be to take the move I am going to in my next change, if you can find it, try castrol gtx startup 10w30 for 3000 miles and see if you see a reduction in your slap.
I wouold be using those buckets of oil if I were you! Why waste the money already spent? It's like trying to talk sense to my 16 year old daughter......hmmm... maybe she is a GM spy?

I am, I am sending them down home with my dad for his friend who is a mechanic and will use it to heat his shop with.
 
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iowa
quote:
Originally posted by KBFXDLI: Thanks guys! So what I am hearing is that I should try Penzoil 10w40 and slap the GM service mgr. with a metal gauntlet......hmmmm....well OK...I'll try it and report back! PS..think the truck's going to like it but not certain about the service guy.....
gimme your address. i will mail you the gauntlet. which hand do you want?
 
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[Off Topic!] Go back up in this topic and you will see why the "reply with quote" is about to be recinded. There are other topics right now with the same thing, so I am not picking on anyone in particular. When you select reply with quote, you can edit out the extra stuff and only reply to the shortened part. I hate 2 long paragraphs of reply with quote and a 1 or 2 line answer. [No no]
 
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I solved my GM 5.3 piston slap problem by trading it in on a Toyota. I even got a transmission that didn't self destruct twice in 13,000 miles!
 
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quote:
Originally posted by 59 Vetteman: [Off Topic!] Go back up in this topic and you will see why the "reply with quote" is about to be recinded. There are other topics right now with the same thing, so I am not picking on anyone in particular. When you select reply with quote, you can edit out the extra stuff and only reply to the shortened part. I hate 2 long paragraphs of reply with quote and a 1 or 2 line answer. [No no]
My Bad, sorry
 
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Messages
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Kansas
quote:
Originally posted by V-MAX: I solved my GM 5.3 piston slap problem by trading it in on a Toyota. I even got a transmission that didn't self destruct twice in 13,000 miles!
It seems your not the only one lately judging from GM's market share.
 
Joined
Jun 3, 2005
Messages
40
Location
NC
I have the same vehicle, 2002 Yukon XL 5.3l, and the same piston slap. Sounds like lifters pumping up, would slap like crazy for about 15-20 seconds and quiet down, but could always make out a tick, tick, tick. The Yukon now has 45,000 miles. Asked the stealership to fix it about a hundred times while it was under warranty. They claimed it to be carbon buildup and normal. The first oils I tried were M1 and Castrol Syntech. 3,000 OCI religously changed. Kept getting worse and worse. Especially the tick. At about 34,000 I put Amsoil S2k 0w30 in it and noticed significant improvement in all running aspects. Still had some slap, but Amsoil helped, and cured the tick. The thing I have found that helped it most is an Auto Rx cleaning, which I am in the middle of the rinse cycle now. The slap was down to 2-3 seconds within a few hundred miles. And I am running my second tank of fuel with FP60 which seems to smooth it all out. Slap is almost gone. FP60 also seems to have helped the power, seems to have added a little zip to it. This vehicle is a great car! Probably the finest automobile I have owned. My first GM, been driving 30 yrs. Drove it from NC to CA, set the cruise on 85 and rolled! We regularly pack 7 adults and tailgating gear in for football/basketball games. To answer the Toyo fans above.... I had a '98 Toyota 4Runner V6 and cured my ails by replacing it with a GMC Yukon. The 4runner had a max speed of 78mph on flat land with two people aboard. The Yukon is a tremendous improvement and we only sacrificed about 2 mpg. The 4runner was 2wd and the Yukon is 4wd, so thats the 2mpg in my book.
 
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Massachusetts
I would check around the net on the 5.3 piston slap. I understand there is a class action lawsuit in the works. A sales friend who works at a GMC dealer told me they give thousands less for a trade in , then wholesale out any truck that has a piston slap.
 
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