Blue smoke on engine start - culprits?
Thread Starter
Launching!
Joined: Nov 2001
Posts: 245
Likes: 0
From: Over There!
Blue smoke on engine start - culprits? I was at the local dealership two weeks ago having the brake discs machined, and saw that each time they started my engine a gout of blue smoke would waft from the tail pipes. I pointed it out to the service staff, and they thought it might be oil in the intake dribbling down to the valves when the engine stops. Okay, I can buy that, since the intake was pretty oily (I just installed the updated PCV valve about three weeks ago). So their thought was to clean up the TB and intake and see what happened.
Well, they did that today and the car still coughs blue on startup (no smoke after start, though). So I have an appointment to have their 'line techs dig in on Wednesday and see what's up. Now, past experience on pre-LS1 SBC's tells me that I'm probably looking at a hosed valve seal or two.
However, to help detect any cattle excrement (not that I expect any - this dealership is kewl), are there any other reasons why the engine would belch blue smoke on startup? Bear in mind, the intake tract from the TB south has been cleaned up, and I am running the updated PCV valve. Thanks!
Well, they did that today and the car still coughs blue on startup (no smoke after start, though). So I have an appointment to have their 'line techs dig in on Wednesday and see what's up. Now, past experience on pre-LS1 SBC's tells me that I'm probably looking at a hosed valve seal or two.
However, to help detect any cattle excrement (not that I expect any - this dealership is kewl), are there any other reasons why the engine would belch blue smoke on startup? Bear in mind, the intake tract from the TB south has been cleaned up, and I am running the updated PCV valve. Thanks!
I can shift faster than you.
iTrader: (21)
Joined: Nov 2001
Posts: 5,133
Likes: 0
From: Baton Rouge, LA
Re: Blue smoke on engine start - culprits? [quote]Originally posted by Big Mike:
<strong>I always thought blue smoke = piston rings?</strong><hr></blockquote>
Blue smoke generally means it is burning oil, whether that be from bad rings, valvestem seals, valve guides, etc.
<strong>I always thought blue smoke = piston rings?</strong><hr></blockquote>
Blue smoke generally means it is burning oil, whether that be from bad rings, valvestem seals, valve guides, etc.
Trending Topics
Re: Blue smoke on engine start - culprits? I'll put money down that it's your valvestem seals. I had this happen w/ my CNC heads way back in '99 on my T/A. My car would puff out a cloud of blue smoke on start-up but was fine once it was running.
As for the rings, they'll typically cause constant oil burning problems compared to just on start-ups.
As for the rings, they'll typically cause constant oil burning problems compared to just on start-ups.
__________________
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
TECH Enthusiast
Joined: Nov 2001
Posts: 543
Likes: 0
From: Richmond, Va
Re: Blue smoke on engine start - culprits? I guarantee that its your valve guide (or valve stem) seals. Ive replaced them on at least 4 cars now, and it fixes the blue smoke at startup everytime. Get you a good spring compressor, an air compressor, and that spark plug to air hose adapter, and you are set. Takes a while to do it, but its worth it. The smoke will get worse and worse as the seals wear out.
TECH Regular
Joined: Nov 2001
Posts: 401
Likes: 0
From: Waxahachie, TEXAS
Re: Blue smoke on engine start - culprits? Valve stem seals.
They aren't hard to change, just don't drop a valve or lose a keeper. <img src="gr_grin.gif" border="0">
I use a magnetic "pen" to keep track of the keepers, and compressed air or the rope trick works well to keep the valves from dropping down.
They aren't hard to change, just don't drop a valve or lose a keeper. <img src="gr_grin.gif" border="0">
I use a magnetic "pen" to keep track of the keepers, and compressed air or the rope trick works well to keep the valves from dropping down.
Thread Starter
Launching!
Joined: Nov 2001
Posts: 245
Likes: 0
From: Over There!
Re: Blue smoke on engine start - culprits? Thanks for the replies, guys! I kinda figured on valve stem seals, but it seemed odd that they would have cooked before 25k miles - thus why I was wondering if there was something LS1-specific that could cause the smoke too. <img src="images/icons/rolleyes.gif" border="0">
Jason:
Thanks for the tips for replacing the seals, but since I still have a warranty I think I'll let the dealer skin their knuckles this time. That'll earn me a bonus 12 months/12k miles to make 'em smoke again on GM's dime... <img src="graemlins/gr_jest.gif" border="0" alt="[jester]" /> As for it getting worse, no kidding! The first time I noticed it, I was standing outside the car when someone else started it. Three weeks later, I can now see a little blue cloud in my mirrors! <img src="gr_eek2.gif" border="0"> Those suckers are going, and fast! Maybe I'm not driving it enough (9k miles in 1 year). <img src="graemlins/gr_jest.gif" border="0" alt="[jester]" />
Jason:
Thanks for the tips for replacing the seals, but since I still have a warranty I think I'll let the dealer skin their knuckles this time. That'll earn me a bonus 12 months/12k miles to make 'em smoke again on GM's dime... <img src="graemlins/gr_jest.gif" border="0" alt="[jester]" /> As for it getting worse, no kidding! The first time I noticed it, I was standing outside the car when someone else started it. Three weeks later, I can now see a little blue cloud in my mirrors! <img src="gr_eek2.gif" border="0"> Those suckers are going, and fast! Maybe I'm not driving it enough (9k miles in 1 year). <img src="graemlins/gr_jest.gif" border="0" alt="[jester]" />
On The Tree
Joined: Jan 2002
Posts: 120
Likes: 0
From: Brick, NJ
Re: Blue smoke on engine start - culprits? Valve seals. Mine did the same thing until I had them replaced. I would not believe it as the heads were only on for a few months, but the seals were not installed correctly and they pulled off the guide.
TECH Enthusiast
Joined: Nov 2001
Posts: 603
Likes: 0
From: Houston
Re: Blue smoke on engine start - culprits? [quote]Originally posted by steve350:
<strong>This is a common defect that chevy has had for years. The valve seals that they use suck.</strong><hr></blockquote>
<img src="gr_grin.gif" border="0">
<strong>This is a common defect that chevy has had for years. The valve seals that they use suck.</strong><hr></blockquote>
<img src="gr_grin.gif" border="0">
