87,000 miles on husband’s truck. Think the Rocker arm is knocking. Is it better to get rid of it or have it fixed. His work truck and we pull a small camper with it too. 2 mechanics have said at least 3 to 4 thousand $ to fix if that is what’s wrong.
For a rocker arm??? No way. There has to be more to this story.
FWIW If you try and trade this truck without fixing it, any good dealer will dock you at least $4000 because of the noise. Any smart private sale buyer will have it checked out by a mechanic and run for the hills when the mechanic tells HIM $3 - $4K. Fix it or sell it, you are going to eat that repair cost either way.
We have decided to fix but isnt there some type of diagnostic that can be done before taking the engine apart. Does the motor really have to come out completely?
And what about trying a motor flush first. Can that be worth it?
Rocker arms don’t usually make a lot of noise, generally it is the lifter. But if a rocker has come loose, it will make a loud clacking sound. The fix is simple, remove the valve cover and adjust (tighten) the rocker nut. Probably about an hour labor plus a new gasket for the valve cover, under $200.
If the noise is due to a lifter collapsing, replacing the lifter will be quite a bit more expensive. However it might help to use motor flush or simply change the oil and filter. A collapsed lifter could be due to gum or sludge causing the lifter to stick or it could be due to a broken spring inside. If a broken spring, no flush or oil change will fix that.
Edit: some mechanics with a lot of experience can tell by the sound what is likely to be wrong, but a more accurate diagnostic will require removal of the valve cover so you will be about $200 into it by then. Carefully select a good mechanic that you will want to do the repair as well as the diagnostics or you will be paying that $200 twice. If your lucky, you might find an older mechanic who can recognize the sound, these problems used to be much more common than today.
Double check with the dealer for warranty. These trucks had 5 years and 100000 mileage power train warranties.
We bought the truck used and no warranty was offered. It had 34.000 miles on it when we bought it and we purchased a 36.000 mile warranty at the time. That is gone as we ar at 86.000 miles.
The warranty travels with the vehicle, so if you own it and it’s still within 5 years/100K, it will apply. I’m guessing you are probably over on time as it starts from the delivery date of the original owner. Any GMC dealer can tell you if it’s still within warranty.
I assume you have the 4.8 or 5.3L engine? These came with cylinder deactivation that used oil pressure (or lack of) to allow the lifters to collapse for improved fuel economy. Those systems are prone to trouble if the oil isn’t regularly changed and kept clean. If they’re talking $3-4K, it’s beyond a rocker arm.
The 4.8 never got cylinder deactivation. The 5.3 did, and you’re correct that lifter problems weren’t uncommon (even with good oil and frequent changes). Google “AFM lifter failure” and you can read a ton of info. As I understand it, the heads have to come off the engine to replace the lifters. That may be where the cost comes in.
Thanks for the clarification on the 4.8.