r/GMT800 • u/powdydoody • 20h ago
Completely rebuilt my 6.0L motor in my garage myself- 1000 mile update
2004 Silverado 2500HD with 236k miles. I recently pulled the motor and completely rebuilt it myself in my garage without even having to take it to a machine shop. Here we are 1000 miles later and figured Id give an update for anyone curious about doing this themselves.
The motor specs: The motor ran perfect prior to rebuild, but was hemorrhaging oil (1qt every few hundred miles), had blue smoke on startup, and had multiple broken exhaust studs.
I ran a compression test prior to teardown and had 170psi on every cylinder, verifying it was in good internal shape still.
I carefully disassembled the motor and measured everything and compared my measurements to the factory rebuild manual. Thankfully, the bores were not out of round, and pistons were still in spec as well.
Crank and cam had no scoring whatsoever and bearings were just mildly worn. The cam bearings were showing just a bit of the copper layer.
I replaced every bearing with the standard size oem replacement - main bearings, rod bearings, and cam bearings. Kept the stock Crank and stock cam.
I replaced all lifters, pushrods, springs, valve seals, retainers, and rockers with oem replacements. I cleaned the valves with my ultrasonic cleaner and lapped them in with lapping compound. Verified seal after with water test.
New piston rings were installed after running the pistons through my ultrasonic cleaner and getting every piece of carbon buildup off.
Every bolt that is a torque to yield bolt was replaced with all new hardware- gm genuine all the way.
Every seal, o ring, and gasket is all new of course.
Installed an oem Melling oil pump and new pickup tube also with new timing chain and gears.
Motor was stripped down to just the bare block and heavily degreased, scrubbed, and pressure washed in my driveway multiple times. Same for the heads.
The heads and block surface all showed no warpage with a straight edge and feeler gauge, so surfaces were cleaned and prepped both with white roloc discs (controversial method but this is what I have always used on my PWC aluminum engine rebuilds and never had an issue. Just dont be dumb with it, lol.
Used fel pro MLS head gaskets
Cylinder bores were just deglazed with a ball hone and honing fluid to regain the crosshatch and clean up the surface.
Everything was put back together, and now I've put almost 1000 miles on the motor driving it and only had a couple of issues:
Radiator blew about 100 miles in. It was the factory oem rad and I knew I should've replaced it when the motor was out, but was trying to save money.
Coolant leak at crossover pipe under the throttle body. I originally used fel pro seals on the oem pipe but found the pipe itself developed a pinhole leak after driving it. The new dorman pipe has had no issues.
Oil level sensor leak. Small oil leak from the oil level sensor. I could not find the original style o ring to reseal the original sensor, and I tried an o ring from a kit I had. It had a small leak, so I replaced the sensor with one that comes with the o ring, and it's all good now.
Other than that, everything else has been awesome! I did oil changes at the following intervals with 5w30 conventional oil:
- changed after immediate startup and running up to temp.
- changed at 50 miles, 100 miles, 500 miles, and now 1000. Next will be at 5000 miles and then every 5k from there, switching to synthetic oil at 5k mark.
Oil did have a small glitter shine to it at initial oil changes, along with a hazy cloudy look from assembly lube. Glitter has gone away after about 500 miles.
Makes 40 psi oil pressure at idle operating temp and feels like it's a new truck.
I can't wait to put another 200k+ miles on it, hopefully!
Feel free to ask anything, I did this all myself in my garage without a machine shop or anyone helping me. Im not a mechanic, Im actually a nurse who just loves working on cars and engines in my free time. So if I can do it, you can too!
This whole process took me about 5 months and right around $2500- including tools I had to buy. Parts were all bought from rockauto.