My in-laws have an 07 Tahoe 4x4 with the 5.3L and cylinder deactivation.
It has started to make a ticking noise that the dealership says is lifters. A quick search sounds like this could be the case, but 24 hours of labor is not cheap.
Another shop wants 19 hours for cam and 8 hours for lifters. On these motors, am I correct in assuming that the lifters would be pulled to remove cam?
And anyone in the Seattle area have any recommendations for a good mechanic? Thanks!
If you need a cam, it because one of the lifters has taken the nose off the lobe, and a new cam with an old lifter will fail, just not quite as fast as a flat tappet cam. If you have lost a cylinder, its because the lifter deactivation mechanism has failed. Either way, the heads come off.
The cams can be changed without pulling lifters apparently. Hot rod magazine talks about that when they are dynoing things.
Yes, you can change a camshaft in an LS motor without pulling the intake or heads. There's some plastic sleeves in the lifter valley that the lifters fit into. If you take out the pushrods and rotate the cam 3t60 degrees, all of the lifters will slide up into the sleeves and stay there.
All that said, they are screwed. The AFM motors are garbage and by the time you figure out it messed u, it ate the cam lobe and wiped the bearings. It will need an entire engine rebuild. This is extremely common in these. In fact, didn't jmthunderbirdturbo on here just go through the exact same thing with his Suburban? Ended up buying a 5.0 F150...
This is what you've got now:
i agree with javelin, it's most likely more than lifters by now. the snaab with the afm 5.3 ate itself alive and now has a non afm 4.8.
How ticky is ticky? My 165k mile Silverado with cylinder deactivation makes more noise than new. The thing is, as far as I can tell the cost to pull it all apart and fix it doesn't make any sense compared to just driving it until the motor eats itself and then putting a new one in.
More i see about the deactivation stuff the more i worry about my grandmothers car, 07 envoy denali 5.3. Anything i could do thats not to indepth to potentially stop the issue before it starts?
Sorry for jacking the thread
Good synthetic oil, lots more changes than the oil life monitor calls for.
chiodos wrote: More i see about the deactivation stuff the more i worry about my grandmothers car, 07 envoy denali 5.3. Anything i could do thats not to indepth to potentially stop the issue before it starts? Sorry for jacking the thread
i hear good things about this one
http://www.rangetechnology.com/pages/v8
i just turned it off in the program via hptuners.
Swap in a non-afm cam and regular lifters with an LS2 (i think) cam sprocket and lifter valley cover then get the pcm reflashed..
Thanks for the input guys; sounds like it likely is a cam and/or lifters going out. I'm not sure how far the dealership went in diagnosing it or how much was just educated guessing, but I bet that's what it is.
Would the cylinder deactivation have anything to do with this? meaning, is it a problem on all of these motors or just the ones with the CD? We have an 08 with the small 4.8 and no cylinder deactivation... any potential issues with these?
They sent me a video of it, and the ticking seemed to be in time with the accessory belt behind the main serpentine (I'm assuming the power steering pump) and I had hopes that it was related to that.
After reading a bunch of internet theories, I advised them to put some seafoam in it, run it for a day or so and do an oil change (unfortunately, they had just done a full synthetic dealer oil change. whoopsie)
I figure it couldn't hurt, and if the lifter is crudded up, maybe this will clean it out. I have next-to-no faith it will work, but it seems to have worked for some.
Only the AFM motors do it, the regular LS's are like gravity. SeaFoam will do you no good, it's done for. This is what you are up against:
The old design is what's in their motor, and it's bad engineering. They fail even when taken absolutely perfectly. The late design is a little better, but still fails. The only way to cure an AFM motor is to get rid of it by swapping all of the lifters and camshaft out for non-AFM. Even just turning it "off" in the PCM will not fix the roller seize.
ah yeah.... that looks inexpensive... definitely not worth the 5% improved gas mileage benefit they have been enjoying for the past 8 years.
thanks for the help!
Afm?
plance1 wrote: Afm?
Active Fuel Management - Basically when the engine is below a certain load threshold it cuts fuel to half of the cylinders and acts like a 4 cylinder.
Does this problem to the newer models as well? I've got a 2012 Silverado with the 5.3 & am wondering if I should be worrying about this.
In reply to FooBag:
Yes, you need to be worried. AFM is flawed engineering.
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