smoke help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

brad20653 · 07-23-2003, 07:31 PM

Im getting a little white smoke when i reb up and water coming out of tailpipe only has 300 miles on engine is it blown up ???

69sixpackbee · 07-23-2003, 07:36 PM

Could be the head gasket, crack in the casting or cylinder liner. Is it missing (running rough)?

71GMC_3/4T · 07-23-2003, 07:52 PM

Lightweight heads on a SBC are prone to cracks. These are usually through the exhaust port into the water jacket in the center two cylinders.
Take them off and fix them before you end up filling a cylinder with water, hydraulic locking it, bending the rod, breaking the piston, etc...
A good shop can magnaflux them and show you the cracks. If they aren't too cracked, some shops will redo the valve seat, which sometimes will hold up.

brad20653 · 07-23-2003, 08:24 PM

no running good i did mess with distrib

Longhorn Man · 07-23-2003, 08:38 PM

Regardless what it is, (kinda soon to jump on saying the heads are nuked) you need to take it apart and fine out where and why.
If it is still running fine, then most of the engine is still good, if you don't rip it apart, it won't be good for long.

cdowns · 07-23-2003, 09:38 PM

i'd check to see that the heads are torqued correctly b-4 taking anything apart

brad20653 · 07-23-2003, 09:59 PM

that can do that ??

GMCrazy · 07-23-2003, 11:20 PM

i second re-torqing the heads. being a new (or rebuilt) motor, the head bolts have a good chance of loosening up during break-in. however, since it's not running horrible, my money's on a cracked head.

beautimus · 07-23-2003, 11:49 PM

hold on a minute......................, have you tried letting it run for a little while?
it could be condensation in the exhaust system.
does the smoke just keep coming ? does it smell like antifreeze?
if not don't tear it down just yet. try letting it run for a little while and see if it clears up. i have had this happen before and it scared
the crap outta me, but it turned out to be ok.
but yeah if it smells like antifreeze, and it just keeps smoking or starts to overheat, i would say you gotta problem.
just my 2 cents worth........
tony

cdowns · 07-24-2003, 09:12 AM

another cause could be intake manifold gasket

SweetandLong68 · 07-24-2003, 09:18 AM

When we are talking about headgasket leaking we are talking about ALOT of thick white smoke. Not just a little bit for a while as with condensation. Of course it could be either one. He didnt describe it to closely.

lata
CHRIS

GMCrazy · 07-24-2003, 11:47 PM

check compression on all cylinders, that should tell you for sure.
b.t.w. i had a cracked head once which produced very little smoke.

07-23-2003, 07:31 PM	#1
brad20653 Senior Member Join Date: Jul 2003 Location: So. MD Posts: 218	smoke help Im getting a little white smoke when i reb up and water coming out of tailpipe only has 300 miles on engine is it blown up ???

07-23-2003, 07:52 PM	#3
71GMC_3/4T Weapons Of Construction Join Date: Apr 2000 Location: Colorado, USA Posts: 1,095	Lightweight heads on a SBC are prone to cracks. These are usually through the exhaust port into the water jacket in the center two cylinders. Take them off and fix them before you end up filling a cylinder with water, hydraulic locking it, bending the rod, breaking the piston, etc... A good shop can magnaflux them and show you the cracks. If they aren't too cracked, some shops will redo the valve seat, which sometimes will hold up. __________________ 1971 GMC 2500, 402/TH400 4.10 Daily Driver Lafayette, CO

07-23-2003, 09:38 PM	#6
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	i'd check to see that the heads are torqued correctly b-4 taking anything apart __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

07-23-2003, 11:20 PM	#8
GMCrazy David Tye Join Date: Jul 2003 Location: Abbeville, Alabama Posts: 52	i second re-torqing the heads. being a new (or rebuilt) motor, the head bolts have a good chance of loosening up during break-in. however, since it's not running horrible, my money's on a cracked head. __________________ David -68 GMC w/327

07-23-2003, 11:49 PM	#9
beautimus Registered User Join Date: Mar 2002 Location: woodstock, alabama, usa Posts: 938	hold on a minute......................, have you tried letting it run for a little while? it could be condensation in the exhaust system. does the smoke just keep coming ? does it smell like antifreeze? if not don't tear it down just yet. try letting it run for a little while and see if it clears up. i have had this happen before and it scared the crap outta me, but it turned out to be ok. but yeah if it smells like antifreeze, and it just keeps smoking or starts to overheat, i would say you gotta problem. just my 2 cents worth........ tony __________________ i survived cancer and kidney stones, but my kids are killing me.

07-23-2003, 07:36 PM	#2
69sixpackbee Registered User Join Date: Jan 2001 Location: Sabinal, Texas Posts: 1,706	Could be the head gasket, crack in the casting or cylinder liner. Is it missing (running rough)?

07-23-2003, 08:24 PM	#4
brad20653 Senior Member Join Date: Jul 2003 Location: So. MD Posts: 218	no running good i did mess with distrib

07-23-2003, 08:38 PM	#5
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Regardless what it is, (kinda soon to jump on saying the heads are nuked) you need to take it apart and fine out where and why. If it is still running fine, then most of the engine is still good, if you don't rip it apart, it won't be good for long.

07-23-2003, 09:59 PM	#7
brad20653 Senior Member Join Date: Jul 2003 Location: So. MD Posts: 218	that can do that ??

07-24-2003, 09:12 AM	#10
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	another cause could be intake manifold gasket __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

07-24-2003, 09:18 AM	#11
SweetandLong68 Your UncleBen Join Date: Dec 2002 Location: Indian Trail, NC Posts: 590	When we are talking about headgasket leaking we are talking about ALOT of thick white smoke. Not just a little bit for a while as with condensation. Of course it could be either one. He didnt describe it to closely. lata CHRIS __________________ 68 C10 shortbed -- Street/Strip

07-24-2003, 11:47 PM	#12
GMCrazy David Tye Join Date: Jul 2003 Location: Abbeville, Alabama Posts: 52	check compression on all cylinders, that should tell you for sure. b.t.w. i had a cracked head once which produced very little smoke. __________________ David -68 GMC w/327



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