KostikaEnvoy said:
I have a 2005 GMC ENVOY XL DENALI and i realy like that car. and i did research and for some reason i can not find any of those engines in canada at all. could some one please give what would be the best thing to do for me with that engine rebuild it ? where can i buy pistons, rods, bearings, lifters? or to swap it with the 6litre? or if any other engines such as sierra, avalanche will fit ? thanks guys will really appriciate that
The 5.3 engine in the Trailblazer/Envoy vehicles is an Aluminum Block version of the Iron Block 5.3 in the full size Trucks, The 6.0 will fit in there, not sure if it will be compatible with the computer and wiring.
Starting in 2005, the 5.3 included a system called "Displacement on Demand" (DOD) in later years it was called "Active Fuel Management" (AFM).
This system utilizes solenoid controlled lifters on 4 of the 8 cylinders to Deactivate them by PCM control under decreased load conditions.
These lifters can fail and stay collapsed which usually causes a tick.
There are other failures that cause engine noises and unfortunately the 5.3 has a history of extreme oil usage that can cause severe engine damage when not monitored closely.
A replacement engine is risky because of these common issues.
Please provide maintenance history on the vehicle to help with advice.
Have you diagnosed the problem? Did the oil go too low and damage the lower end or are you experiencing a lifter failure tick at the valve train?
Some have replaced the bad DOD lifters (expensive parts) and had success with the repair. Extreme oil usage is usually a combination of a defective Driver side Valve Cover and sticky Piston Rings.
Good luck with this and hope you get it back on the road.
