LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Leak Down Testing

Thread Tools
 
Search this Thread
 
Old Jun 4, 2011 | 04:09 PM
  #1  
LarsV8's Avatar
Thread Starter
Launching!
 
Joined: Feb 2010
Posts: 246
Likes: 0
From: Houston
Default Leak Down Testing

Fresh rebuild, first oil change had chocolate milk colored oil. Perhaps there was condensation build up in the sitting motor or the machine shop didnt assemble correctly.

I have suspicions of a bad head gasket. From what I understand, I should do a leak down test.

Is there a guide somewhere? Any other tests I should do.

Thanks!
Reply
Old Jun 5, 2011 | 04:30 AM
  #2  
96LT1355Z28's Avatar
10 Second Club
15 Year Member
Photogenic
Photoriffic
Liked
iTrader: (2)
 
Joined: Nov 2007
Posts: 841
Likes: 9
From: Holden, MO (KC)
Default

How did it run, how do the plugs look, did it smoke, is there oil in the intake, or in the coolant? What makes you suspect a head gasket other than the oil, what did the "fresh rebuild" consist of? As far as a leak down test Google/ Youtube is your friend! More info will probably net you more responses.
Reply
Old Jun 5, 2011 | 10:44 AM
  #3  
02v8ta's Avatar
TECH Resident
iTrader: (8)
 
Joined: Jun 2008
Posts: 958
Likes: 0
From: south jersey
Default

For the cooling system right? Its simple doesn't really warrant a write up. But as suggested go on youtube and look it up. Your only other option is a compression test of the cylinders. More of a PITA.

Drain your coolant, let it sit a day or two and see if an oil puddle forms on top of it like mine Just because the coolant looks good with the cap off doesn't mean anything
Reply
Old Jun 5, 2011 | 02:41 PM
  #4  
LarsV8's Avatar
Thread Starter
Launching!
 
Joined: Feb 2010
Posts: 246
Likes: 0
From: Houston
Default

Originally Posted by 96LT1355Z28
How did it run, how do the plugs look, did it smoke, is there oil in the intake, or in the coolant? What makes you suspect a head gasket other than the oil, what did the "fresh rebuild" consist of? As far as a leak down test Google/ Youtube is your friend! More info will probably net you more responses.
I pulled the motor, did a LE2 head/cam package with all the usual maintenace stuff - reground crank, new rods, pistons, freeze plugs, oil pump, bearings, etc.

I haven't pulled the plugs. There looks to be a tiny bit of white smoke, but not a ton. Can't really see it outside, but if its in the garage with exhaust facing the inside you can see it kinda accumulating and flowing out the open bay door.

I didn't see any oil in the coolant, which I swapped out when I replaced the distributor this past weekend. I havent looked in the intake either.

I thought chocolate milk colored oil was a tell tale blown head gasket sign.
Reply
Old Jun 5, 2011 | 02:52 PM
  #5  
02v8ta's Avatar
TECH Resident
iTrader: (8)
 
Joined: Jun 2008
Posts: 958
Likes: 0
From: south jersey
Default

Originally Posted by LarsV8
There looks to be a tiny bit of white smoke,

I thought chocolate milk colored oil was a tell tale blown head gasket sign.
The white smoke is another confirmation, it'll only get worse. Stick a camera or buddy behind it if you're still running it to see.

The milk oil is the tell tale sign but you should have other symptoms to, as stated one or more of your plugs will be showing signs. The white smoke is another. Your coolant can also be discolored.

Hows it running? Not over heating? Are you loosing any coolant?
Reply
Old Jun 5, 2011 | 02:57 PM
  #6  
LarsV8's Avatar
Thread Starter
Launching!
 
Joined: Feb 2010
Posts: 246
Likes: 0
From: Houston
Default

Seems to be running okay, although I am not sure what normal is since this is a fresh rebuild on a high powered car. I don't run it long enough to overheat because I read the water in the oil can ruin bearings.

Will this work?

http://www.youtube.com/watch?v=QA7KV...yer_detailpage

Last edited by LarsV8; Jun 5, 2011 at 03:03 PM.
Reply
Old Jun 5, 2011 | 03:02 PM
  #7  
02v8ta's Avatar
TECH Resident
iTrader: (8)
 
Joined: Jun 2008
Posts: 958
Likes: 0
From: south jersey
Default

If you just changed the oil / coolant or both no! This is how i was going to go about it until i read up on it. It'll effect the results having fresh oil/coolant in it. It reads some chemical reaction mojo or such that'll be in the coolant after cycling for awhile.

Rent the Cooling system pressure test from autozone and see how that works. Mine failed quick
Reply
Old Jun 5, 2011 | 03:06 PM
  #8  
LarsV8's Avatar
Thread Starter
Launching!
 
Joined: Feb 2010
Posts: 246
Likes: 0
From: Houston
Default

Will do, thanks man!
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

6 Gifts Neither Your Dad Nor Grad Will Shove Into the 'Trinket Drawer'

 Brett Foote
story-1

Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?

 Pouria Savadkouei
story-2

Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine

 Verdad Gallardo
story-3

7 Most Reliable High-Performance Engines GM Has Ever Built

 Verdad Gallardo
story-4

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

 Verdad Gallardo
story-5

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-6

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-7

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-8

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-9

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
Old Jun 5, 2011 | 06:23 PM
  #9  
LarsV8's Avatar
Thread Starter
Launching!
 
Joined: Feb 2010
Posts: 246
Likes: 0
From: Houston
Default

Got the pressure tester from Autozone.

Pumped it up to 15 PSI and I had some leaking on top hose where it connects to the intermediary pipe with the bleeder screw. Tightened it up and stopped the leak there.

Started up the car and it idle for 2 minutes. Pressure increased to 18 PSI and held constant for two minutes.

I still feel like something is not right.
Reply
Old Jun 5, 2011 | 06:40 PM
  #10  
02v8ta's Avatar
TECH Resident
iTrader: (8)
 
Joined: Jun 2008
Posts: 958
Likes: 0
From: south jersey
Default

I know the feeling, mine failed the pressure test but is still running strong, no smoke or over heating. Maybe i'll dump the oil again soon on mine but for as far as your engine maybe do the same, like you said just condensation maybe?

Someone else with some more know how might able to suggest something else. Good luck.
Reply




All times are GMT -5. The time now is 09:16 AM.

story-0
6 Gifts Neither Your Dad Nor Grad Will Shove Into the 'Trinket Drawer'

Don't get dad new socks or a grill brush this year.

By Brett Foote | 2026-06-09 14:55:56


VIEW MORE
story-1
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?

Slideshow: We take a close look at the ONE and Artidiag 800BT2 diagnostic tools from Topdon and the reasons to buy one over the other.

By Pouria Savadkouei | 2026-05-28 11:05:11


VIEW MORE
story-2
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine

Slideshow: The controversial Ferrari F6 swaps its original flat-12 for a Corvette Z06-derived LT4 V8 and sends power to four rear wheels through a custom-built drivetrain.

By Verdad Gallardo | 2026-05-26 18:23:54


VIEW MORE
story-3
7 Most Reliable High-Performance Engines GM Has Ever Built

Slideshow:These GM engines didn't just make huge power, they survived abuse, boost, track days, and six-digit mileage with a reputation for refusing to quit.

By Verdad Gallardo | 2026-05-21 16:45:27


VIEW MORE
story-4
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-5
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-6
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-7
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-8
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-9
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE