[Tonyman89]

I've been hearing so much myths about the GM piston slap. To be honest, I really don't care about the problem, as it is just a way for people to throw money away for something not needed. Long story short, my Impala 3.4 makes this ticking sound when cold after being started, the goes away afterwards. I didn't noticed any "blue smoke" out the tail pipe, fouled spark plugs, weak compression, horrible gas mileage, and loud clattering noise after engine is at normal operating temperature. I also went to look inside the valve cover with the oil cap off to see if that noise was indeed oil going to the rockers arms. As it was idling and ticking, I noticed the oil dripping down the rocker arm to the spring as the noise alleviates. But anyway, to me that "ticking then goes away when warm" noise is nothing but the oil circulating to the rocker arms. That's my opinion what is yours?

The car has been doing it since we bought in May 07 with 62K miles.

The ticking noise does not happen in my Corolla or my dad's Silverado 4.3. Just only the Impala is the victim.

 

[DrewImpala]

To the best of my knowledge and what I know about cars. Impalas and other GM v6 engines use Hypereutectic pistons which are silicone and aluminum. As well are blocks are made of aluminum too. Back to science class now for a second. Aluminum expands when if gets hot. Thats why so many car have a weird sound for a few minutes after starting when it's cold. Generally it's called "engine flex". That mixed with the pistons creates that noise for about the first 2-5 minutes upon starting the car when cold. And to my knowledge Toyota uses cast pistons and I'm not sure about the Silverado but i believe they are cast as well. Someone correct me if I'm wrong but this is how my auto teacher explained it to me back when I got my Impala and asked about the weird noise when the engine is cold.

 

[Tonyman89]

yes thats true, aluminum expands when heated. i'm not sure what pistons are in my impala. The Corolla might have aluminum parts, but cast iron block, I assume. The Silverado is cast iron block and heads, possibly cast iron pistons. That 4.3 engine is anachronistic, new truck with old fashioned design.

 

[DrewImpala]

yes thats true, aluminum expands when heated. i'm not sure what pistons are in my impala. The Corolla might have aluminum parts, but cast iron block, I assume. The Silverado is cast iron block and heads, possibly cast iron pistons. That 4.3 engine is anachronistic, new truck with old fashioned design.

All gen 7 Impalas as well as many other models(3.1l 3.4l 3.5l 3.8l and 3.9 motors i know of for sure) use hypereutectic pistons. As far as the 4.3l being anachronistic that is true for all GM. The 3800 engine came out in the 80s, the 3400 engine is the same block as a 3100 just bored over and how long and how many models use the Small Block engines. But hey. If its not broke then why fix it.

 

[kingnutin]

Piston slap is a sort of heavy knocking rattling sound though, what you are describing sounds like a sticky lifter.

 

[Tonyman89]

Piston slap is a sort of heavy knocking rattling sound though, what you are describing sounds like a sticky lifter.

Yes, it sounds like a lifter issue, well what can I do to unstick the lifter?

 

[kingnutin]

You can try some seafoam or marvels or something like that, I wouldn't run it in there for long though, then change the oil. It usually is oil varnish on the moving parts hanging it up, if you change your oil as often as you should it will probably clear itself up.

 

[Tonyman89]

oh i do change oil on it regularly but it still makes that noise. Doesn't really bother me much. I havent ran any oil flush in it whatsoever.

 

[kingnutin]

Well, you could try it. But like I said, don't run it in there for too long. That stuff cleans, but the oil isn't able to lubricate while that stuff is in there. Best bet is to warm the engine up to operating temp, pour the stuff in the oil, and run it for 10-15 minutes, then change the oil. It may not clear it up right away, in fact it may not at all, but its worth a shot. A sticky lifter won't really hurt anything, but they are obnoxious, and can eventually collapse.

 

[Tonyman89]

For real? If I don't take any action, the lifter will collapse?

 

[kingnutin]

CAN collapse, it may or may not. A collapsed lifter isn't the end of the world anyway, it will just keep that valve from opening correctly and cause rough running and fouling of the plug.

 

[Tonyman89]

Oh no, I don't have to worry about that, my Impala doesn't have any fouled plugs whatsoever. When I replaced the plugs at 80K miles and I showed my auto teacher my old plugs, he said i have "damn" good cylinders. I know I'm in good hands. But I will run something in the engine before I change the oil. Maybe seafoam or something of that nature.

 

[Gregg-O]

One of the few 'fix in a can' products I have used with success is Rislone, try a qt with your next oil change or 2, see what happens.

 

[Tonyman89]

No thanks, I'll just do a motor flush with Solder Gunk and then change the oil.