Soules75

Hey everyone,

I have a 2004 Silverado 5.3L that is smoking pretty bad on start up after it has been sitting overnight or after work. About a month or so ago I had the water pump replaced because I was losing coolant, but that didn't solve the smoke on start up. To me the smoke looks kind of bluish, so I am thinking I maybe have leaking valve stem seals? Here is a video I took today of the smoke...

smoke on startup.mp4 - YouTube

Does it look like blue smoke to you guys? If so, do you think it's the valve stem seals? It only smokes for a few seconds like in the video, then it stops and is fine for the rest of the day. Truck is closing in on 99,000 miles.

philbilly20

How hard have you drove it????

Soules75

I don't beat on it, I drive it nicely. Any ideas guys? I would really appreciate some input. Thanks.

therewolf

It looks like it needs valve seals to me.

Generally blue smoke(it is, BTW) on start-up

is the tell for bad valve seals.

Not a super difficult or expensive job...

Soules75

Thanks for the help. Would you be able to give me a ballpark estimate of what it might cost to get this repaired by a local mechanic? Are we talking $150-$300 or are we talking $400+?

My brother knows his way around these trucks pretty well, but I am not sure if this is something he could fix relatively easily or not. Any input would be great! Thanks.

91Caprice

Could be an issue with the PCV valve as well which is common on these 5.3's.

therewolf

Correct-o-mondo. It's pretty easy to fix. I'd try changing the PCV valve first.

Then see if your valve-cover gaskets(sticky PCV valves blow them out )

are still OK or leaking. IF you have to pull your valve covers off to replace the

gaskets, or the blue smoke gets worse, I'd replace the valve seals then.

They are under the valve springs, at the top of the heads, right under the

valve covers.

I used to use compressed air to pressurize the cylinder through the

spark plug hole, so when I compressed the spring the valves stayed in the

up position. One cylinder at a time. No big deal. IMO, your brother should

be able to take care of it.

Soules75

Thanks for all your help guys. Now I have a good place to start.

therewolf

BTW, Soules75,

Welcome to the Chevy Forums.

Be sure to try our "thread search" feature. Many times a

troubleshooting problem was covered in a prior thread.

chamokie

All of the above, the only thing I would add is make sure you check the valve guide for wear, if the valve is "sloppy" in the guide, seals may not cure your issue. You would have to pull the head and have a valve job done on it.