Piston Slap Or Lifters?

[crepitus]

sometimes when i start my truck in the moring it ticks very loud for like 2-3 seconds. i have read about the lifter problem on AFM motors as well as piston slap. How can you tell the difference between them?

[Draenor]

The piston slap should have been resolved in the GMT900s. Its most likely the lifters. If you have piston slap, the engine would sound like a diesel at start up.

[crepitus]

The piston slap should have been resolved in the GMT900s. Its most likely the lifters. If you have piston slap, the engine would sound like a diesel at start up.

that is what it sounds like. i was actually going to put that in the description of the sound.

[pm26]

The piston slap should have been resolved in the GMT900s. Its most likely the lifters. If you have piston slap, the engine would sound like a diesel at start up.

 

It should have been, but it wasn't. As it is, it is a crap shoot. If you get a truck whose dimensional differences between cylinder bores and piston diameters are minimal, you are not likely to have a piston slap problem any time soon.

[c4cruiser]

My 08 VortecMax has a 2-3 second kncok sound on cold startup, but it's nothing like the piston slap that my 99 5.3 motor had. The lifters for the AFM motors may be what you are hearing. I wonder if these lifters bleed down some after sitting overnight or for a number of hours?

[Z45]

My 2008 motor is quiet, no noise in 12,000 miles.

 

Could be the oil filters you are using?

[crepitus]

My 2008 motor is quiet, no noise in 12,000 miles.

 

Could be the oil filters you are using?

its a gm filter. truck only has 1k miles on it.

[Z45]

Any noise in the first few seconds of engine start up are nothing to be concerned about IMO. Its takes a few seconds for the oil to reach all the areas of the engine. Also, lots of dissimilar metals in today's engines that expand at different rates. You got a big chunk of metal and plastic with thousands of parts, something bound to make noise.

[C. Charles Hahn]

My '08 with the aluminum block 5.3 does the same thing sometimes when it's cold; it also has only 1500 miles on it. It does sound more like a lifter issue on mine, though it could also be due to the tight tolerances of the cylinders, block, and heads.... just has to warm up a bit for more clearance.

 

Just curious, though - do you have the aluminum block or the iron block? I would have to bet the iron block motors would have more severe issues with this than the aluminum block, simply because of the different rates of expansion of iron and aluminum (even on iron blocks, the heads are aluminum). Just a thought....

[crepitus]

My '08 with the aluminum block 5.3 does the same thing sometimes when it's cold; it also has only 1500 miles on it. It does sound more like a lifter issue on mine, though it could also be due to the tight tolerances of the cylinders, block, and heads.... just has to warm up a bit for more clearance.

 

Just curious, though - do you have the aluminum block or the iron block? I would have to bet the iron block motors would have more severe issues with this than the aluminum block, simply because of the different rates of expansion of iron and aluminum (even on iron blocks, the heads are aluminum). Just a thought....

mine is a iron block. my last truck had an aluminum black and never made any noise when it started up but was alot more nosier when running in general. alot of ticking noises compared to the 08. and it doesnt make the noise on every cold start up just every once in a while.

[98 Z71 SLT]

Lifters...dang dude.

 

you are going back to dealer AGAIN with this 08...

 

I feel your pain

 

TSB's all over the place on AFM lifters failing.

 

Keep us updated. FWIW, my 08 Sierra, iron block *J* engine, NEVER made a sound on startups...

[crepitus]

Lifters...dang dude.

 

you are going back to dealer AGAIN with this 08...

 

I feel your pain

 

TSB's all over the place on AFM lifters failing.

 

Keep us updated. FWIW, my 08 Sierra, iron block *J* engine, NEVER made a sound on startups...

i do park the truck on quite an incline. steep driveway. dont know it that makes a difference

[pm26]

Lifters...dang dude.

 

you are going back to dealer AGAIN with this 08...

 

I feel your pain

 

TSB's all over the place on AFM lifters failing.

 

Keep us updated. FWIW, my 08 Sierra, iron block *J* engine, NEVER made a sound on startups...

No noise so far in my '06 5.3 liter cast iron block, AFM-less engine after roughly 8k miles.

[pm26]

Lifters...dang dude.

 

you are going back to dealer AGAIN with this 08...

 

I feel your pain

 

TSB's all over the place on AFM lifters failing.

 

Keep us updated. FWIW, my 08 Sierra, iron block *J* engine, NEVER made a sound on startups...

 

Stealth,

 

just how many of those AFM lifters are failing? It the failure mileage related or more random? How difficult is the lifter replacement and have the replacement lifters been redesigned? Does GM understand why the lifters are failing? Is it the inconsistent quality during the manufacture or some design flaw?

Every dealer I talk to always tells me there are no problems at all with them, but of course they will tell you only what you want to hear to sell you a truck.

 

Let's say you deactivate the AFM with a custom tune. Would these special lifters still tend to fail even if they are deactivated?

This topic should be of great interest to AFM engine owners.

 

I have test driven several AFM equipped '08 trucks so far and cylinder switching on all has been seamless. Of course, I have no idea what happens 10k miles later, and whether that switching becomes rougher and more noticeable.

 

There are definitely great deals out there. Today I priced a new '08 2WD LT1 crew cab 1500 truck with 5.3, rear locker, tow package, convenience package, power seat, and bedliner for $ 20k (sticker was $ 31,500). What is interesting is that they have additional rebates on certain trucks depending on how long they have been sitting on dealer's lots. So the red tag price is not necessarily the final price you pay.

[Ranger]

My J code engine (iron block) makes a bit of noise when it's cold...I've even had a few comments from people that say something like "why's your truck louder" or something like that, my grandmother actually thought I had turned the idle up or something...After it warms up to operating temp it quiets down a lot but still has a slight "stumble" to it while idling.