r/GMT800 • • 13h ago

Completely rebuilt my 6.0L motor in my garage myself- 1000 mile update

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250 Upvotes

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:

  1. 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.

  2. 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.

  3. 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.


r/GMT800 • • 8h ago

Just joined thanks for having me

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42 Upvotes

07 Silverado classic 1500 4x4 Z71
200k on body 150k on engine and trans


r/GMT800 • • 3h ago

My lil shit - 223k miles

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8 Upvotes

r/GMT800 • • 5h ago

Thoughts on the brushed aluminum Chevy badge?

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9 Upvotes

r/GMT800 • • 7h ago

What else to replace

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14 Upvotes

If you had your truck this far apart, what else would you replace. We have a new engine/trans/T-case/drive shafts, new front diff, tie rods, ball joints, and wheel bearings.

I think I'm going to go ahead and get new pitman/idler arms, since they apparently suck to replace. Do the actual steering boxes wear out? Truck has about 225k on it.

Edit to say this is a 2006 2500HD.


r/GMT800 • • 3h ago

My lil shit - 223k miles

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4 Upvotes

r/GMT800 • • 48m ago

Thanks for the Add

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• Upvotes

Thinking about building the 4.8L in this truck any cam recommendations for a naturally aspirated build?


r/GMT800 • • 1h ago

L0W 01L PRTCHER T1NG5

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• Upvotes

BARB COMPLAININ BOUT TAPS C0MING 4ROM ENGYN WEHN S1TTN IDOL 4 TO L0NG


r/GMT800 • • 1h ago

Anyone running KSP upper control arms?

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• Upvotes

Just got my KSP uppers this morning, stock uppers were squeaking and balljoint boots ripped so figured go ahead and replace them before winter. Also used a camber locking alignment kit so I can align it evenly myself and prevent it from falling out of alignment. So far so good!


r/GMT800 • • 7h ago

Rodent messed up a pair of injectors and coils is it fixable or do I have to do a whole harness? I just finished the engine a few months ago.

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6 Upvotes

r/GMT800 • • 20m ago

Steering clunk still not resolved

• Upvotes

Well, I’ve got the infamous steering rattle/clunk but this one goes an extra mile. I purchased the replacement Dorman upper intermediate shaft and the intermediate shaft bearing like all of the videos on YouTube suggested. I went to replace the shaft but discovered that the shaft was completely seized. I worked on it for a couple of days and ultimately took it to a shop for replacement as I couldn’t get it to budge. The shop replaced the shaft and the bearing and called to let me know that the clunking problem I was having still wasn’t resolved. They seemed surprised that the problem still existed and speculated that something further inside the steering column was causing the problem. I fear that I may have let the clunking problem persist a bit too long but really didn’t think too much of it because this problem has been known to go for years, some never even fix it. I bought the truck about 6 months ago and it’s great otherwise; one owner 2006 GMC Sierra 2500hd 6.0 with 78k miles. Has anyone else had this issue? TIA


r/GMT800 • • 4h ago

2000 Silverado 4x4 fuel filter

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1 Upvotes

r/GMT800 • • 12h ago

Suggestions for front end rebuild kits with level

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3 Upvotes

r/GMT800 • • 4h ago

AC

1 Upvotes

Ok so I need some help. I purchased a 2000 GMC Sierra 1500 SLE extended cab because it was my dream truck. Got a couple issues with it and would like to work on it myself. The ac is not blowing cold air, only cool. Did a test on the ac and it shows it’s at 50 psi and then when the compressor kicks on, it drops to 20, then back to 50 psi. Happens every 15 seconds. Any suggestions?


r/GMT800 • • 14h ago

What Do Y'all Think About This 2006 Tahoe?

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4 Upvotes

r/GMT800 • • 15h ago

Leak issue

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5 Upvotes

I’ve got an 05 Silverado which I’m having some water getting into the cab issues. We don’t get much rain where I live so I don’t see the issue often but every time it rains it happens.
It’s on the passenger side, part of the carpet gets soaked, and there’s water droplets on the trim. When I’m driving at road and highway speeds through the rain I can literally hear water dripping somewhere in that area. Any tips?


r/GMT800 • • 21h ago

Prepping to start transmission removal (4L60E, ‘99 z71). Any tips or advice? PFA

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16 Upvotes

Just let me know! I’m a first timer so I’d love to hear stories or hazards, victories and times when you had to tow it to a shop. Thanks!


r/GMT800 • • 1d ago

Which colors would you paint your GMT800 interior?

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16 Upvotes

My base color is the light tan, and I grabbed a dash top to replace my severely cracked one. It's a dark grey so I'm going to paint it with SEM I think. I'm leaning 1 or 3 - 1 looks the most 'luxurious' (and I'd probably wind up doing some other trim pieces like on the door and stuff) but 3 looks the most "oem" for a split color setup.

Not pictures is a 2006 escalade wood grain wheel I'll be adding in as well, so that probably makes the 1/3 look nicer as well with the wood matching the 'leatherish' colors.

Any thoughts?


r/GMT800 • • 10h ago

02 Escalade blocked sunroof drain

1 Upvotes

Hey guys as the title says I have an 02 Escalade that has a blocked passanger front sunroof drain. This is causing water to back up and dripping at a fitting I found inside the a pillar trim. I’ve snaked drains before, but for the life of me I cannot get my weed eater line down the drain, get about 4-5 inches before it gets bound up. I have the headliner dropped slightly and can see a sharp bend in the drain tube, I’m assuming that’s where I’m getting caught up at. Anyone have any tips or advice on a good method to get that drain cleared out? I didn’t want to use air, as I heard the drain line comes disconnected from the cassette pretty easily, and it looks like a real PITA to get to if that occurs.


r/GMT800 • • 21h ago

I need help finding

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8 Upvotes

Hello guys I’m here because I need help I heard Reddit is the most helpful place if you have any questions and I have one im looking to buy this bumper that’s discontinued I’m wondering if anyone knows where I could find one or anything like that. If anyone has one that they want to get rid of and sell please let me know text me and let me know what price and we can work something out 🙏🙏🙏


r/GMT800 • • 23h ago

How does she look for 20 years old?

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11 Upvotes

Just got new tires, can’t wait to take her off-road!


r/GMT800 • • 23h ago

More of my GMT800 builds

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8 Upvotes

The red one was made for a friend, his grandpa owns that one, Cateyes are next!


r/GMT800 • • 1d ago

Imagine not owning a gmt800. Wack

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18 Upvotes

r/GMT800 • • 1d ago

Anyone recognize this piece?

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26 Upvotes

Found on the floor near the pedals. 2006 escalade. Not sure if it came from my truck or if it got tracked in on my boots


r/GMT800 • • 23h ago

Why would these needles be so dim? Did I not sit them right or is it that they’re just like that?

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5 Upvotes

So I just installed my cluster that I rebuilt and the needles are kinda dangerously dim. This is full brightness and I actually like that the backlight isn’t bright as hell but the needles are way darker than even the oem orange needles. When I test drove it I tried to read what my exact speed was but it’s too dam hard to see the dim blue needle. I got them from redlinespeedgauges and they seem to be good quality just it don’t light up enough for when am driving at night which I always do for leaving work and I am not trying to get another speeding ticket since my work area is heavily transited by police. I am thinking of returning them and getting the chrome ones on eBay maybe they could be brighter but idk.
( this picture does not do justice to how actually dim they are. And they are unevenly lit so it looks spotty with some brighter and darker areas.