Piston Slap Update - It's gone - I think

[Cuplable]

I've got an '02 Impala with the 3.4L and used M1 5w30 from 40k to 80k miles. In the last 20k I've really noticed what alot of others here have complained about....piston slap. About two weeks ago, based on info obtained here, I switched to Havoline Dino 10w30. After two weeks, I think (or I wanna think) that the piston slap is gone. My wife is wondering why I'm starting the car every morning and sticking my head on the engine. But then her sister reminds her that I'm odd. (Love it when she comes to visit).

Anyway, I actually think my piston slap is gone. Now, I'm not touting Havoline as miracle juice, but at least my car likes it. I think I'll stick with Havoline 10w30 until late fall when I'll switch to Havoline 5w30.

If anyone else has a GM 3.4L, maybe this solution will work for you, too!

 

[T-Keith]

piston slap = the sky is falling

This is probably the most overdiagnosed automotive problem, even ahead of low blinker fluid.

Good to hear the Havoline made your car quieter, must be the moly.

 

[G-MAN]

Piston slap is a well documented fault with the GM 3.1 and 3.4 engines.

In my experience, oils with a good dose of moly in them do tend to quiet the noise. And Havoline has a lot of moly in it.

 

[michaelc80]

There is ample evidence that piston slap is a well known problem in many GM engines. There are dozens of website that show this is a significant problem. Here are just a few that show the level of the problem.

PistonSlap.com

LemonLaw.com

GMProblems.com

Piston slap can lower the value of the vehicle by $4,000 to $6,000, and given the number of cases I don't know how it can be considered "overdiagnosed". I think Cuplable is smart to do as much as possible to quiet it down.

 

[mshu7]

In general, it seems like a LOT of people reference "piston slap" anytime they are referring to engine noise in GM engines.

Maybe it's just me, but it seems like people are quick to jump on the "piston slap" band wagon. My 3.4L V6 in my Grand Am GT is loud too, but I honestly don't think it's piston slap. I just thing it's noisey rockers or something. Plus, Mobil1 has the tendency to make engines sound louder.

If I seem out of line or wrong about the whole band wagon thing, I appologize. It's just referenced so much when people talk about any GM engines, it's kind of hard not to think that way.

Anyway, sorry to hi-jack your thread Cuplable.

On-topic though, I'm on an ARX cycle on my GAGT with Havoline. It definitely makes the engine quieter than Mobil1 did for the last 85K miles. Although, I still love Mobil1. It has treated me well. The engine is spotless on the inside (looking through filler hole). The only reason I did the ARX is b/c I hit 100K and wanted to make sure there wasn't any gunk in the engine that I couldn't see. Plus, I'm switching over to Green GC after I'm done with the ARX cycle.

 

[Cuplable]

I would agree with many of you that Piston Slap could be in the minds and ears of the beholder. However, I let my attorney diagnose my exposure, my doctor diagnose my ills, and the guy next door who owns a couple of auto shops diagnose my piston slap!

I got him to stick his head in the engine compartment and he thinks it’s less noisy than before. He did mention that the root problem, the design, is still with me. He then called me manic and when sat down and had a beer and discussed how to keep the boys in the neighborhood away from our daughters.

I not trying to start any “tastes great – less filling” arguments over this whole piston slap issues, I just wanted to let the BITOG gang know about my experience.

 

[sgtgeek]

quote:

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Originally posted by michaelc80:
[QB] There is ample evidence that piston slap is a well known problem in many GM engines. There are dozens of website that show this is a significant problem. Here are just a few that show the level of the problem.

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Sure lots of folks got their BVD's in a wad for sure.....however...it ( piston slap) is a noise the engine makes...not a performance or longevity issue....It's the length of the piston skirts.....
and for the record...I just find it funnier than heck that folks will jump all over the mfg engineers over this but challenge anybody that promotes/recommends another oil outside of the mfg recommended oils claiming " the engineers know best".....

 

[boxcartommie22]

i am beggining to wonder if synthetic fluids cause slap and they seem to go away with dino fluids...

 

[sgtgeek]

That would be my experiance....^^^^

 

[74 Laguna]

Originally posted by boxcartommie22:
i am beggining to wonder if synthetic fluids cause slap and they seem to go away with dino fluids...

That was my experience the one and only time I used Mobil 1. I ran it for less than 20 miles, drained it and went back to Motorcraft and no more noise.

 

[GoldenRod]

Piston slap in the GM 3.1L V6 and 3.4L V6 is caused by the piston pin bores being oversized on the original pistons.

 

[G-MAN]

quote:

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Originally posted by GoldenRod:
Piston slap in the GM 3.1L V6 and 3.4L V6 is caused by the piston pin bores being oversized on the original pistons.

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That is a separate issue. These engines have piston slap problems too. The REALLY noisy ones have the wrist pin problem you mentioned PLUS piston slap. The two sounds are very distinct and very different. The wrist pin clearance problem gives off a very sharp metallic tapping noise. Piston slap (depending on how many pistons are slapping) is more like a muted rattle--almost like the sound of a diesel at idle.

 

[427Z06]

quote:

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Originally posted by sgtgeek:
...I just find it funnier than heck that folks will jump all over the mfg engineers over this but challenge anybody that promotes/recommends another oil outside of the mfg recommended oils claiming " the engineers know best"....

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Manufacturing defects and poor design, are quite different issues.

 

[Al]

In the past RedLine was said to improve the problem. So I'm not surprised that the dino oil with the highest level of moly helps quiet it as G-Man mentioned.

And those of us who have hade the 3.1/3.4 its not a figmant of the imagination. It sounds like a diesel. Its as impossible to miss as a freight train going through your living room.

 

[tamu_man]

My buddy has the 3.4 in his heap. Redline and M1 TSUV made the noises stop. My recomendation is never buy a GM V6 or V8 again until they get their crap together. There are plenty of alternatives in the Dodge and Ford lineups.

 

[GoldenRod]

tamu_man:

I've made some unsubstantiated, outlandish, reckless posts; but I think you're about to surpass me.

 

[Ray H]

quote:

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Originally posted by sgtgeek:
Sure lots of folks got their BVD's in a wad for sure.....however...it ( piston slap) is a noise the engine makes...not a performance or longevity issue....It's the length of the piston skirts.....

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Right you are! When GM's engineers maximized useable bore length in small block engines for displacement gain to meet customer power demand, traditional piston skirt length proportions had to be altered. (For those of you uncomfortable with the mild noise of a little harmless piston slap, try the cacophony of shorter connecting rods meeting traditional length piston skirts at bottom dead center...

) Big block engines are always extra fuel guzzling weight. (Can you say, "CAFE", people?) Big blocks don't fit comfortably into frontwheel drive intermediate body engine bays, either. Of course it didn't take long for litigation-happy shark lawyers to start churning the waters around GM's remaining capital well, either.

My dad bought a 1960 Dodge Dart built just after a horrendous steel worker's strike that virtually closed all of GM and Chrysler plants for lack of deliveries. (Ford managed to ride the strike out for awhile with reduced production due to their own mill whose workers were represented by the UAW.) Once the strike was settled, QC was not a priority for Chrysler as the automaker struggled to deliver orders taken just before the strike and rebuilding post-strike inventory. (When was QC ever a priority at Chrysler?) The 318 V8 in dad's car had some piston slap from the getgo and it definitely affected vehicle life.

On the Group I (if they were that good...) based 30 straight viscosity weight detergent motor oils of the period (no API "S" or ILSAC "GL" ratings back then [shoot, no ILSAC back then for that matter] nor did dad trust the available multi-viscosity oils), the car only lasted a little over the 175,000 miles of ten years' use. Oh, yeah, the car got rear-ended while it was parked on the street. The trunk was compressed nearly forward to the rear window, so dad's insurance carrier totaled the car out. But, I'm sure the car's premature demise was really the result of that piston slap "problem", huh?

 

[tamu_man]

There are three free kittens in a basket. You choose the one that has three legs that's blind in one eye, has half a testicle, and no hair and it ticks like a clock. I'm sure it will last a while, but it's still not as desirable to most people as one that has everything in order.

If I have $20-$30 grand to spend, or even $10 grand on a used car, I'm going to put it into a car that doesn't make funny noises. Some funny noises are OK like we've afore mentioned, others kill cars. I'm no mechanic, but I'd be happier if my car just ran like everyone elses products. I'm not saying other brands don't make noises, but GM products seem to take the cake.

 

[G-MAN]

As for brands that make noise, I have yet to hear a Honda at idle that didn't sound like it had a faint lifter tick to me. And this includes the one I owned. And yet Honda makes bulletproof engines.

 

[sgtgeek]

quote:

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Originally posted by tamu_man:
There are three free kittens in a basket. You choose the one that has three legs that's blind in one eye, has half a testicle, and no hair and it ticks like a clock. I'm sure it will last a while, but it's still not as desirable to most people as one that has everything in order.

If I have $20-$30 grand to spend, or even $10 grand on a used car, I'm going to put it into a car that doesn't make funny noises. Some funny noises are OK like we've afore mentioned, others kill cars. I'm no mechanic, but I'd be happier if my car just ran like everyone elses products. I'm not saying other brands don't make noises, but GM products seem to take the cake.

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Going on "sound" only is very dangerous....Julia Roberts laughs through her nose so I guess you'd walk on that "bargain" also huh?!