SaabCentral Forums banner

1 - 5 of 5 Posts

·
Registered
Joined
·
2,082 Posts
Discussion Starter #1
Hi guys,

Weird question, as I normally am posting over in the OG 9-5 forums. I actually don't have a 9-7X, but I do have a 2009 Suburban, which to my knowledge has the same engine as the 5.3 version of the 9-7Xs. I don't post in any GM or Chevy forums, so I thought I'd try here with my fellow Saabers. :)

So my 2009 Suburban has 170,000 miles. Original engine. A few days ago it started having the dreaded lifter tick on the AFM bank of cylinders. I used some Liqui Moly hydraulic lifter additive and that has quieted the thing down...for now. I also said "what the heck" and bought one of those AFM disablers that you plug into the OBD port so the truck always stays in V8 mode.

Just curious if anyone has tried the AFM disabler on their 5.3, or if anyone has had issues with the AFM systems in their vehicles. Thanks!
 

·
Super Moderator
Joined
·
1,464 Posts
The AFM systems that GM has rolled out over the years have always had some negative side effects. The valvetrains are less reliable than non-DOD/AFM versions. Many newer cars have transmission shudder issues too (6 and 8 speed autos) because GM tunes slip into the TCC to mask the V4 imbalance during DOD/AFM operation. So, I’m really not a fan. If you do a bunch of light throttle cruising, it will save some gas, but not sure it’s worth the hassle. If you are at 170,000 miles with that original valvetrain, you did good IMO.

The Range AFM Disabler is the most common. I used it on my Camaro for a few hundred miles before I bought tuning software and permanently shut off AFM. But the Range unit worked well.
 

·
Registered
Joined
·
2,082 Posts
Discussion Starter #3
The AFM systems that GM has rolled out over the years have always had some negative side effects. The valvetrains are less reliable than non-DOD/AFM versions. Many newer cars have transmission shudder issues too (6 and 8 speed autos) because GM tunes slip into the TCC to mask the V4 imbalance during DOD/AFM operation. So, I’m really not a fan. If you do a bunch of light throttle cruising, it will save some gas, but not sure it’s worth the hassle. If you are at 170,000 miles with that original valvetrain, you did good IMO.

The Range AFM Disabler is the most common. I used it on my Camaro for a few hundred miles before I bought tuning software and permanently shut off AFM. But the Range unit worked well.
Yeah, I went ahead and bought the AFM disabler from Range. We'll see how that goes. We had a 2001 Yukon XL (also with the 5.3) that seemed to be bulletproof. We sold it with 305,000 miles, still running fine (burning quite a bit of oil at that point, but what you'd expect).

This 2009 has been a little fussier. It had lifter tick once before, and we chalked it up to a clogged AFM oil filter. Replaced oil pressure sensor at the same time. That was probably a year ago, and the lifter tick returned a couple days ago. I put some Liqui Moly hydraulic lifter additive in there, and that seems to have quieted it down (for now). I am probably just buying time at this point. The truck is in great shape, so even if I have to replace the lifters, I'll probably do it. Question is, should I replace them with standard parts and disable AFM altogether? I believe there are other parts you have to replace too, besides just the AFM lifters (different camshaft, different oil pump, remove AFM solenoid thingy, etc.).

Thanks for the reply. I know I'm probably technically not supposed to be posting about GM cars in here, but I thought it'd be OK since some 9-7x's share the same engine as my 2009 Suburban.
 

·
Super Moderator
Joined
·
1,464 Posts
It’ll be easier to replace the lifters with the same parts that came with the truck. There’s more to permanently disabling AFM than just the lifters (for the reasons you mentioned). And if you decide to sell it, the next owner can use AFM if they really want to.

No worries on this thread! Good info.
 

·
Registered
Joined
·
2,082 Posts
Discussion Starter #5
It’ll be easier to replace the lifters with the same parts that came with the truck. There’s more to permanently disabling AFM than just the lifters (for the reasons you mentioned). And if you decide to sell it, the next owner can use AFM if they really want to.

No worries on this thread! Good info.
Got my Range AFM disabler today. Installed it in the OBD port and went for a long-ish drive. I have a few initial thoughts.
  • The car seemed like it would shake a lot at idle. That is reduced significantly when the car isn't allowed to go into V4 mode.
  • The oil pressure at idle is 5-10 PSI higher at idle if the car never goes into V4 mode.
  • Overall everything just seems smoother. Switching between V4 and V8 mode to me felt clunky.
Overall, the device did exactly what it said it would do. I wish I'd had gotten it a long time ago. My larger concern is if the lifters can be saved or not. Car ran smooth as could be tonight, with not even a hint of noise from the top end. Fingers crossed!
 
1 - 5 of 5 Posts
Top