Gray smoke coming out of my exhaust, time for a rebuild?

[GrayMonster03]

I know this is an old subject and many have said its "normal for our cars", but is it really? The car has 65k miles with mods/tune. Gray smoke usually appears at startup, after sitting a while, or sometimes even randomly. Never while im driving though, unless I really gun it. Friends have told me they see a cloud of smoke exit my exhaust when I floor my ported blower. The driver side head was serviced like most 03 Cobras years ago. Maybe PCV failure? I'm wondering if its worth removing the heads to have a look at the valve guides. I've done a top end rebuild on a SOHC and don't really want to do it on my Cobra :nonono:
Hopefully an oil separator will do the trick. What experience do you guys have with this issue?

 

[BO TY KLR]

I'm guessing pvc issue. I'm betting you've got quite a bit of oil laying in lower intake also. Every time I've had my blower off there had always been 2-3 ounces laying in there. Finally just put breathers on engine and eliminated pvc altogether. No more puddling in intake and startup smoke is gone.

 

[hotcobra03]

I have seen this alot...could be from tune


ive seen mustangs without blower smoke on start up...


than 65k..lack of use

 

[Givens]

I would start with an oil separator, my car has one on it and I pour a few ounces out of it every few 100 miles. If I take it to the track same thing will happen. It catches a lot more oil than you would think,I imagine you have a lot of oil being sucked back in and sitting it the bottom of the blower.

 

[GrayMonster03]

All replies were helpful, thanks everyone. I will definitely invest in a separator and take it from there.

 

[BadBlue98GT]

Another thought...replace your valve seals. While you have relatively low mileage, depending on your driving habits, your valve seals may sit without any action (oiling) for awhile and have started to wither away, so-to-speak. My '98 GT did the same thing, gray smoke at start up which disappeared after the car warmed up, and the consensus was the valve seals were shot.

 

[mfrazier2]

If im not mistaken, Blue/Grey smoke- burning oil, Black smoke- burning to much fuel, White-burning coolant

 

[mikeeeb124]

I bought mine with 7300 miles a few years ago(10k now) Mine used to shoot a puff of smoke on cold start up, like after sitting in the garage over night, or at a car show for the day. Talk about embarrassing starting up and seeing a plume of smoke...anyway, I went in and replaced all 32 valve stem seals. Took care of my smoke issue entirely. I had used an oil catch can previous to replacing the seals and it didn't take care of it. It's a fun job to do and while I was inside the covers I took them to get powder coated right away :-D

 

[Rambro]

I'm guessing pvc issue. I'm betting you've got quite a bit of oil laying in lower intake also. Every time I've had my blower off there had always been 2-3 ounces laying in there. Finally just put breathers on engine and eliminated pvc altogether. No more puddling in intake and startup smoke is gone.

Eliminating the PCV also cured my smoking at startup. When I took my blower off and seen that puddle of oil in the intake it was all the convincing I needed. I also has a separator and a pre filter before the PCV delete.

 

[Bdubbs]

It could also be a leaky injector. I had smoke on startup's periodically and it was a leaky injector. Those were oem injectors and once I swapped to the 60's it was gone. Also that one spark plug was more brown than all the others and had a tint of fuel smell. Worth pulling plugs to check things out.