blue exhaust on startup
|
|
|
View Full Version : blue exhaust on startup blue exhaust on startup bhw33191 10-04-2008, 10:29 AM Blue Bowtie 10-04-2008, 11:39 AM A bit of oil smoke on cold startup is not unusual on SBC engines. The original valve stem seals quickly harden and don't actually offer a lot of sealing. There is usually very little oil consumed, and it isn't enough to foul spark plugs nor damage the catalytic converter. I'd be surprised if you'll even see a change in oil level between changes due to leaking valve stem seals. In other words, if the oil is due to leaking valve stem seals, it's not actually a a problem, but merely a nuisance in some cases. It's also a sign that oil is actually reaching the valves and that burning provides a little extra upper cylinder lubrication on cold starts. j cAT 10-04-2008, 11:47 AM other causes would be the oil is not draining back into the sump quick enough...head drain holes gooped up, and the valve guides need work, as these engines have a problem here...as manufactured.. If this continues remove the valve cover and inspect for sludge... bhw33191 10-04-2008, 08:54 PM Yeah it hasnt done it since it last did this morning so i think it was just from starting it 10 times one after the other when i was messing with my battery. silicon212 10-05-2008, 10:24 PM That puff of smoke is nothing to worry about. Do worry about it if it doesn't stop smoking for several seconds after the engine is started. As Blue Bowtie stated, valve stem seal leakage most often causes that puff, it's common on an older engine that uses O-ring seals like the Chevy engines, and will not cause more than a 1-2 tablespoon per 1k mile increase in oil consumption. If the engine only puffs for a second or so, then you won't have to worry about it being anything other than a hardened O-ring stem seal. If the drainback hole in the head plugged, it would smoke a lot more than that. bobss396 10-06-2008, 09:36 AM You probably had it loaded up from turning it off and on. Personally, I don't trust a small block Chevy that doesn't emit a puff of smoke now and then. Bob bhw33191 10-06-2008, 02:48 PM You probably had it loaded up from turning it off and on. Personally, I don't trust a small block Chevy that doesn't emit a puff of smoke now and then. Bob Haha. good to know gatoratoy227 10-07-2008, 07:15 PM its very common to see an older SBC smoke a tiny on start up even if its not every time you start it older o-ring seals are garbage if you have the disire to do so if the smoke bothers you remove the heads and have them rebuilt but a little oil in the cylinders isn't a bad thing upper cylinder lube hicker-billy style Related Links Participate in thousands of discussions at AutomotiveForums.com! Registration is absolutely free. |