Pm26...updated Afm Thread...

98 Z71 SLT · November 11, 2008

I scrolled thru some old threads, and caught up to where you want to know more about AFM system.

http://gsi.xw.gm.com/si/showDoc.do?docSysk...710&from=sm

pip 4344

http://gsi.xw.gm.com/si/showDoc.do?docSysk...622&from=sm

08-06-01-018b

http://gsi.xw.gm.com/si/showDoc.do?docSysk...751&from=sm

pip 4499

Well, there are now (3) AFM related lifter TSB's out there. I have them listed off, and if a pop-up is inop, you can research the actual pip/tsb number.

Cylinder de-activation does NOT have to happen to have a faulty lifter. I have heard BRAND NEW trucks with 1 mile , ticking like a timebomb. (Truck was dealer-traded last Jan.) The stock 8 lifters are NOT failing, the 8 AFM lifters ARE the ones that are failing.

We have seen 3 cases (that I know of...I don't see every repair order!) One '07, and two '08's. One '08 owner just wanted the noise "looked at" he didn't want a fix...seems like he didn't really care.

Design flaw? Poor manufacture? I'm gonna say YES to both. There is obviously a tolerance problem inherent to these AFM lifters, and that's why we already have 3+ TSB's on them.

Deactivate AFM...could a lifter still act up?? Certainly. A Tune doesn't change the overall build of the AFM lifter.

As far as SEAMLESS...that's a load of crap. My old 08 was like riding in a blender with AFM on, between 25-29 mph. It was horrible. It never gave me any noises though...just alot of buzzing/vibration.

Do we see AFM failures every week? No. Every month? No. It is random, and can happen on ANY AFM equipped model.

To fix, the cylinder heads must be pulled, to gain access to the AFM lifters.

The good thing??? We have a 5yr / 100k mile powertrain warranty going for us.

If AFM is the ONLY thing holding you back from a purchase, don't let it!! You have warranty!!

ALSO, If you like the New Body Style, but if you are DEAD-SET against AFM, I still have an answer for you. Get a 4.8 Pickup. They ARE available, and have NO AFM system.

pm, I know you are considering an upgrade...let me know if you are still shopping...

VMax2007 · November 11, 2008

As far as SEAMLESS...that's a load of crap.

Not on mine it's not. I have tried to feel it and I cannot. It is 100% seamless.

No lifter noise yet...18K miles.

98 Z71 SLT · November 11, 2008

Dang it

I see the pop-ups are not working now...

Maybe MS3DALE can throw them in this thread?? pip and tsb numbers are already there...

jrrod2004 · November 11, 2008

I scrolled thru some old threads, and caught up to where you want to know more about AFM system.

http://gsi.xw.gm.com/si/showDoc.do?docSysk...710&from=sm

pip 4344

http://gsi.xw.gm.com/si/showDoc.do?docSysk...622&from=sm

08-06-01-018b

http://gsi.xw.gm.com/si/showDoc.do?docSysk...751&from=sm

pip 4499

Well, there are now (3) AFM related lifter TSB's out there. I have them listed off, and if a pop-up is inop, you can research the actual pip/tsb number.

Cylinder de-activation does NOT have to happen to have a faulty lifter. I have heard BRAND NEW trucks with 1 mile , ticking like a timebomb. (Truck was dealer-traded last Jan.) The stock 8 lifters are NOT failing, the 8 AFM lifters ARE the ones that are failing.

We have seen 3 cases (that I know of...I don't see every repair order!) One '07, and two '08's. One '08 owner just wanted the noise "looked at" he didn't want a fix...seems like he didn't really care.

Design flaw? Poor manufacture? I'm gonna say YES to both. There is obviously a tolerance problem inherent to these AFM lifters, and that's why we already have 3+ TSB's on them.

Deactivate AFM...could a lifter still act up?? Certainly. A Tune doesn't change the overall build of the AFM lifter.

As far as SEAMLESS...that's a load of crap. My old 08 was like riding in a blender with AFM on, between 25-29 mph. It was horrible. It never gave me any noises though...just alot of buzzing/vibration.

Do we see AFM failures every week? No. Every month? No. It is random, and can happen on ANY AFM equipped model.

To fix, the cylinder heads must be pulled, to gain access to the AFM lifters.

The good thing??? We have a 5yr / 100k mile powertrain warranty going for us.

If AFM is the ONLY thing holding you back from a purchase, don't let it!! You have warranty!!

ALSO, If you like the New Body Style, but if you are DEAD-SET against AFM, I still have an answer for you. Get a 4.8 Pickup. They ARE available, and have NO AFM system.

pm, I know you are considering an upgrade...let me know if you are still shopping...

Hey Super Stealth, those that do not have a user id and password they get the following:

You are not authorized to view the requested information.

wlvrn1215 · November 11, 2008

24,000 on mine good to go!

crepitus · November 11, 2008

well i have a small tick or knock sometimes during cold startup. lasts from 1-3 seconds. i was thinking of having the dealer look at it but i dont want my trucks engine, with 1k miles on it torn apart. it could be a lifter or maybe piston slap. only time will tell and since i have the 5 year warranty i will just wait until its very bad or the engine grenades and they have to replace it.

Steveman · November 11, 2008

Yeah mine is a seamless transition. People who have ridden with me never believe it when I say my V8 is only using 4 of its cylinders, it is that smooth. Also I notice no noise difference what so ever and I have pretty good hearing.

VMax2007 · November 11, 2008

well i have a small tick or knock sometimes during cold startup. lasts from 1-3 seconds. i was thinking of having the dealer look at it but i dont want my trucks engine, with 1k miles on it torn apart. it could be a lifter or maybe piston slap. only time will tell and since i have the 5 year warranty i will just wait until its very bad or the engine grenades and they have to replace it.

1-3 seconds is normal. The TSB for the AFM lifters require it to last more than a minute or 2 to be considered an issue.

pm26 · November 11, 2008

Thanks for the info Stealth. The AFM problems look like a crap shoot - just like the piston slap. A few have a bad case of it, some no noise at all.

I was actually looking to replace my car and considering a 2WD truck as they can be bought for about the same price as an average midsize car.

And yes, I know about the 4.8 engine and would prefer to have that, except that most trucks have the 5.3 as it can be ordered as a part of the power package which gives you other options as well.

Most trucks that have 4.8 liter V8 around here are either work trucks or LS package trucks. LT1 or LT2 trucks with a 4.8 l are very rare and hard to find here. \

I was looking at some vehicles today and this dealer had about 50 new 2008 trucks in stock, including a new 2007. Yes, I keep finding brand new 07's for sale around here as well. But you can actually buy a new 2008 truck for less than an identical '07 left over. There are simply higher incentives on most 08s.

As for cars, the red tag sale is B.S. Last month I could have bought a new Chevy Impala for about $ 2k less due to better rebates and $ 1k bonus GM card money (on top of my earnings). Trucks are still the best bargain.

I test drove a new 09 Chevy Cobalt SS turbo and it was a blast! Quite a fast little car, and good handling too. 260 Hp and 5 speed manual transmission. Except that I can buy a new 2008 2WD Silverado crew cab LT1 with remote start , 5.3, tow pkg, locker, and other goodies for $ 18,500 (including my GM card $ 1,500 rebate) and The Cobalt is $ 21,000!!!!!!!! Go figure.

Bowtie2Sierra · November 11, 2008

As far as SEAMLESS...that's a load of crap.

Not on mine it's not. I have tried to feel it and I cannot. It is 100% seamless.

No lifter noise yet...18K miles.

+1

3800 miles on my '08 and AFM remains 100% seamless. I had 13k miles on my '07 when I sold it and never had any AFM issues on that one either. Hopefully my luck holds out.

msinawsk · January 7, 2009

i think i have this problem... went out and heard it this morning..it is def ticking. anyone have the tsb for it?

J-man67 · January 16, 2009

The switch on mine is seamless, but def ticking like a bomb on cold start-ups. I too would like to see the NEWEST bulletin as I was just told by my dealer that it states not to replace them, which I think is BS!

Ryan00TJ · January 16, 2009

3300 miles here with no ticking. AFM is seamless and I like it. I wonder could a customer ask GM to replace the 4 AFM lifters with regular lifters and disable the AFM. With standard Hyd Roller lifters there would be no problem. If I ever have this problem I will more than likely replace them myself even though I have a warranty. I trust myself more than a paid mechanic. Plus these engines are easy to work on.

VMax2007 · January 16, 2009

3300 miles here with no ticking. AFM is seamless and I like it. I wonder could a customer ask GM to replace the 4 AFM lifters with regular lifters and disable the AFM. With standard Hyd Roller lifters there would be no problem. If I ever have this problem I will more than likely replace them myself even though I have a warranty. I trust myself more than a paid mechanic. Plus these engines are easy to work on.

There are 8, not 4. 4 intake and 4 exhaust.