Questionable 5.3
Questionable 5.3 
Is this engine worth installing? This is another 5.3 I already own. Guy I got it from said it came out Tahoe with bad trans with 120k. He claimed to have ran it and said no obvuous signs of problems.
TECH Resident
Joined: Mar 2012
Posts: 858
Likes: 402
From: Texas
What are your plans for it? How much does he want for it?
If it's a cheap price, I'd go for it, but replace the head gaskets and resurface the heads. While the heads are off, check them with a straight-edge to make sure the block is okay.
Take a couple of rod and main caps off and see how the bearings look.
If all that checks out, replace the front and rear cover seals, oil pump and barbell, and run it.
It looks kinda crusty in the crankcase area, and there are differing opinions on engine flushes, but that's a whole other discussion.
If it's a cheap price, I'd go for it, but replace the head gaskets and resurface the heads. While the heads are off, check them with a straight-edge to make sure the block is okay.
Take a couple of rod and main caps off and see how the bearings look.
If all that checks out, replace the front and rear cover seals, oil pump and barbell, and run it.
It looks kinda crusty in the crankcase area, and there are differing opinions on engine flushes, but that's a whole other discussion.
What are your plans for it? How much does he want for it?
If it's a cheap price, I'd go for it, but replace the head gaskets and resurface the heads. While the heads are off, check them with a straight-edge to make sure the block is okay.
Take a couple of rod and main caps off and see how the bearings look.
If all that checks out, replace the front and rear cover seals, oil pump and barbell, and run it.
It looks kinda crusty in the crankcase area, and there are differing opinions on engine flushes, but that's a whole other discussion.
If it's a cheap price, I'd go for it, but replace the head gaskets and resurface the heads. While the heads are off, check them with a straight-edge to make sure the block is okay.
Take a couple of rod and main caps off and see how the bearings look.
If all that checks out, replace the front and rear cover seals, oil pump and barbell, and run it.
It looks kinda crusty in the crankcase area, and there are differing opinions on engine flushes, but that's a whole other discussion.
4.8 engine
TECH Fanatic
Joined: Dec 2017
Posts: 1,467
Likes: 265
From: Bossier City, Louisiana
I'd use the dirty 5.3 and go with it. Yes, it appears to have suffered poor oil change service but at only 120,000 miles, it still has a great many good miles remaining. Giving it short but hot oil change intervals will clean up a lot of that grunge. Clean up the bottom of the pan, of course, but also the oil pump screen.
I agree with most of the advice above but I would also recommend changing the knock sensors and their wire harness while you are at this stage. It'll never be easier than right now. But I would not tamper with the bearing caps.
If this engine has not been ran for a while or if it is going to sit for a while, purge the ethanol fuel out of the injectors. The corn liquor in gasoline these days is not kind to a fuel injector sitting for a long time. Clean them now or clean them later but clean them you must.
I'd also periodically rotate the crankshaft to limit valve spring fatigue.
Rick
I agree with most of the advice above but I would also recommend changing the knock sensors and their wire harness while you are at this stage. It'll never be easier than right now. But I would not tamper with the bearing caps.
If this engine has not been ran for a while or if it is going to sit for a while, purge the ethanol fuel out of the injectors. The corn liquor in gasoline these days is not kind to a fuel injector sitting for a long time. Clean them now or clean them later but clean them you must.
I'd also periodically rotate the crankshaft to limit valve spring fatigue.
Rick
What are your plans for it? How much does he want for it?
If it's a cheap price, I'd go for it, but replace the head gaskets and resurface the heads. While the heads are off, check them with a straight-edge to make sure the block is okay.
Take a couple of rod and main caps off and see how the bearings look.
If all that checks out, replace the front and rear cover seals, oil pump and barbell, and run it.
It looks kinda crusty in the crankcase area, and there are differing opinions on engine flushes, but that's a whole other discussion.
If it's a cheap price, I'd go for it, but replace the head gaskets and resurface the heads. While the heads are off, check them with a straight-edge to make sure the block is okay.
Take a couple of rod and main caps off and see how the bearings look.
If all that checks out, replace the front and rear cover seals, oil pump and barbell, and run it.
It looks kinda crusty in the crankcase area, and there are differing opinions on engine flushes, but that's a whole other discussion.
Whats one of the ways to clean the bottom end?
I'm not a fan of the stock valve springs and would replace without least a fresh LS6 or better valve spring etc.
Trending Topics
TECH Fanatic
Joined: Dec 2017
Posts: 1,467
Likes: 265
From: Bossier City, Louisiana
As noted above, clean the oil pan and the pump screen. After that, frequent, as in every 500 miles, oil and filter changes will go a long way towards cleaning up the interior of that engine. Make the oil changes while the engine is good and hot . . . not on a cold engine. The detergents and cleansers in the oil will do a relatively good job at cleaning the bottom end up. Quite simply, your engine did not have its oil changed often enough by its previous owners.
I'd be lying if I said I never did it but I have used small amounts of Chevron Techron and AC Delco X66P poured into the engine oil to quiet a noisy lifter on my 1999 Ford F-150. But I really don't recommend this course of action to clean up the bottom end of a dirty engine - too risky. It works but can work much too well and too quickly with all of that extra cleanser dislodging too much dirt and grunge into crankshaft bearings and the oil pump screen.
Yes, you see and hear the success stories on You Tube about the glory of using Sea Foam, Techron and other products to clean and quiet old engines. But I don't think we ever hear about the complete failures that can happen.
Rick
I'd be lying if I said I never did it but I have used small amounts of Chevron Techron and AC Delco X66P poured into the engine oil to quiet a noisy lifter on my 1999 Ford F-150. But I really don't recommend this course of action to clean up the bottom end of a dirty engine - too risky. It works but can work much too well and too quickly with all of that extra cleanser dislodging too much dirt and grunge into crankshaft bearings and the oil pump screen.
Yes, you see and hear the success stories on You Tube about the glory of using Sea Foam, Techron and other products to clean and quiet old engines. But I don't think we ever hear about the complete failures that can happen.
Rick
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo I'd use the dirty 5.3 and go with it. Yes, it appears to have suffered poor oil change service but at only 120,000 miles, it still has a great many good miles remaining. Giving it short but hot oil change intervals will clean up a lot of that grunge. Clean up the bottom of the pan, of course, but also the oil pump screen.
I agree with most of the advice above but I would also recommend changing the knock sensors and their wire harness while you are at this stage. It'll never be easier than right now. But I would not tamper with the bearing caps.
If this engine has not been ran for a while or if it is going to sit for a while, purge the ethanol fuel out of the injectors. The corn liquor in gasoline these days is not kind to a fuel injector sitting for a long time. Clean them now or clean them later but clean them you must.
I'd also periodically rotate the crankshaft to limit valve spring fatigue.
Rick
I agree with most of the advice above but I would also recommend changing the knock sensors and their wire harness while you are at this stage. It'll never be easier than right now. But I would not tamper with the bearing caps.
If this engine has not been ran for a while or if it is going to sit for a while, purge the ethanol fuel out of the injectors. The corn liquor in gasoline these days is not kind to a fuel injector sitting for a long time. Clean them now or clean them later but clean them you must.
I'd also periodically rotate the crankshaft to limit valve spring fatigue.
Rick
As noted above, clean the oil pan and the pump screen. After that, frequent, as in every 500 miles, oil and filter changes will go a long way towards cleaning up the interior of that engine. Make the oil changes while the engine is good and hot . . . not on a cold engine. The detergents and cleansers in the oil will do a relatively good job at cleaning the bottom end up. Quite simply, your engine did not have its oil changed often enough by its previous owners.
I'd be lying if I said I never did it but I have used small amounts of Chevron Techron and AC Delco X66P poured into the engine oil to quiet a noisy lifter on my 1999 Ford F-150. But I really don't recommend this course of action to clean up the bottom end of a dirty engine - too risky. It works but can work much too well and too quickly with all of that extra cleanser dislodging too much dirt and grunge into crankshaft bearings and the oil pump screen.
Yes, you see and hear the success stories on You Tube about the glory of using Sea Foam, Techron and other products to clean and quiet old engines. But I don't think we ever hear about the complete failures that can happen.
Rick
I'd be lying if I said I never did it but I have used small amounts of Chevron Techron and AC Delco X66P poured into the engine oil to quiet a noisy lifter on my 1999 Ford F-150. But I really don't recommend this course of action to clean up the bottom end of a dirty engine - too risky. It works but can work much too well and too quickly with all of that extra cleanser dislodging too much dirt and grunge into crankshaft bearings and the oil pump screen.
Yes, you see and hear the success stories on You Tube about the glory of using Sea Foam, Techron and other products to clean and quiet old engines. But I don't think we ever hear about the complete failures that can happen.
Rick
I plan on replacing the heads with the clean 862 heads(which have new valve springs)
Intake will be replaced with ls6 intake with new stock 5.3 injectors unless I end up changing the cam, then I would get injectors according to cam..
What about that Gunk stuff to clean the engine?? Anybody still use that?? I'm pretty good with regular oil changes but will remember to change oil while engine is still hot..
I plan to run the engine with mail order tune before I install in car.. Also a compression and leak down test since the engine is out..
Last edited by 86CAMARO400HP; Jul 27, 2019 at 11:57 AM.
TECH Fanatic
Joined: Dec 2017
Posts: 1,467
Likes: 265
From: Bossier City, Louisiana
Yes, I used some of that "Gunk" spray product to clean my engine but only the engine and transmission external surfaces. Not a drop was sprayed into the guts of the motor. With some Gunk and a wire brush, my engine cleaned up on the outside very nicely.
Somebody will soon correct me if I'm wring but I don't think that stock 5.3 liter LM7 injectors will fit an LS6 intake. Same for LM7 injectors and an LS6 wiring harness. The styles and part numbers are different.
Rick
Somebody will soon correct me if I'm wring but I don't think that stock 5.3 liter LM7 injectors will fit an LS6 intake. Same for LM7 injectors and an LS6 wiring harness. The styles and part numbers are different.
Rick