Nightclaw

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!

Jason99T/A

iTrader: (21)

I would guess the valvestem seals are worn out. Mine were shot at 20k miles!

Big Mike

iTrader: (4)

I always thought blue smoke = piston rings?

Jason99T/A

iTrader: (21)

[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.

BluVette

Valve stem seals.

zombiedude

iTrader: (1)

or that PVC crap <img src="graemlins/gr_barf.gif" border="0" alt="[barf]" />

DanZ28

iTrader: (5)

Most likely a seal or two since it's only on start up..

Trevor @ Texas Speed & Perf.

iTrader: (3)

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.

01 SS Jay

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.

AgaveCorvette

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.

Nightclaw

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]" />

Red98C5

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.

SteveD

This is a common defect that chevy has had for years. The valve seals that they use suck.

2000SS

[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">