Oil leaking from #8 header tube? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

HotRodGMC68 · 08-06-2013, 01:15 PM

About a month ago I freshened up the top end on my 384 (new springs, seals, had the heads inspected and surfaced, new exhaust seats installed) since then I've been noticing oil coming from around where the #8 header tube is welded into the header flange. My valve cover is not leaking on it. I have no other trace of oil on or around the head. I've pulled the plug out and it's as clean as can be, no trace of oil on it. Also no sign of excess oil making its way into the cylinder. Anyone have any thoughts?

Thanks..

BR3W CITY · 08-06-2013, 07:23 PM

I had a 1/16 nylon line for gauge pressure chafe a small hole and spray oil mist only when the oil heated up. Hard to diagnose until it finally gave all the way and hosed stuff.

**Captainfab** · 08-06-2013, 11:36 PM

Is your dipstick on the drivers side or passenger side? If it's on the passenger side, maybe you're getting a little blowby out of it.

Marv D · 08-07-2013, 11:21 AM

When a SBC has oil leaks on the passenfgers side ya always gotta ask of there is a bolt and sealer on the front mount bolt that goes into the fuel pump pushrod cavity.

Next suspect is the rear seal of the intake manifold. I haven't used anything but a tall bead of "the Right Stuff' for end seal gaskets in a couple decades. Once in a great while I'll mess up setting the intake into place and get a leak (more with this stupid tunnelram and any others) But a weep at the corners will run down between gap between the head and block created by the headgasket,, and drip off. Depending on starter (full size or mini and clocking) I've had it drip onto the headers. If you used the cork or neopren end gaskets I'd sure take a GOOD look with a mirror to see if there is a weep at the back of the intake.

FYI there is no oil (pressurized or otherwise) passing through the head except what is pumped UP the pushrods, and the drainback holes that return the oil to the INTAKE GALLEY. If you have oil on the outboard side of the head, it's coming from the rocker cover, or weeping down from the intake end seals.

Just a word of caution,,, oil on the headers is a real potential for a underhood fire. If worst comes to worst, get a bottle of the dye and a light to trace the source.

Hertzdaddy · 08-12-2013, 08:08 AM

It sounds like you are saying its on the inside of the header. I had something similar when a exhaust valve seal went bad on a fresh install. I don't know why it went bad but it would either load up on the seated valve or oil down the piston after sitting for a while. Maybe check your plug and see if its burning any oil?

shortbed70 · 08-18-2013, 01:17 PM

If it's on the flange and nothing from the outside it points to a ring not sealing or valve guide or seal bad letting oil by
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08-06-2013, 01:15 PM	#1
HotRodGMC68 Registered User Join Date: Aug 2005 Location: Albuquerque, New Mexico Posts: 32	Oil leaking from #8 header tube? About a month ago I freshened up the top end on my 384 (new springs, seals, had the heads inspected and surfaced, new exhaust seats installed) since then I've been noticing oil coming from around where the #8 header tube is welded into the header flange. My valve cover is not leaking on it. I have no other trace of oil on or around the head. I've pulled the plug out and it's as clean as can be, no trace of oil on it. Also no sign of excess oil making its way into the cylinder. Anyone have any thoughts? Thanks.. __________________ 384 Stroker Small Block- Best ET: 13.24@103

08-06-2013, 07:23 PM	#2
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: Oil leaking from #8 header tube? I had a 1/16 nylon line for gauge pressure chafe a small hole and spray oil mist only when the oil heated up. Hard to diagnose until it finally gave all the way and hosed stuff. __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

08-06-2013, 11:36 PM	#3
Captainfab 60-66 Nut Join Date: Mar 2007 Location: Coeur d'Alene, Idaho Posts: 23,246	Re: Oil leaking from #8 header tube? Is your dipstick on the drivers side or passenger side? If it's on the passenger side, maybe you're getting a little blowby out of it. __________________ Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE

08-07-2013, 11:21 AM	#4
Marv D Registered Truck Offender Join Date: May 2008 Location: hells training ground (aka Ariz) Posts: 3,118	Re: Oil leaking from #8 header tube? When a SBC has oil leaks on the passenfgers side ya always gotta ask of there is a bolt and sealer on the front mount bolt that goes into the fuel pump pushrod cavity. Next suspect is the rear seal of the intake manifold. I haven't used anything but a tall bead of "the Right Stuff' for end seal gaskets in a couple decades. Once in a great while I'll mess up setting the intake into place and get a leak (more with this stupid tunnelram and any others) But a weep at the corners will run down between gap between the head and block created by the headgasket,, and drip off. Depending on starter (full size or mini and clocking) I've had it drip onto the headers. If you used the cork or neopren end gaskets I'd sure take a GOOD look with a mirror to see if there is a weep at the back of the intake. FYI there is no oil (pressurized or otherwise) passing through the head except what is pumped UP the pushrods, and the drainback holes that return the oil to the INTAKE GALLEY. If you have oil on the outboard side of the head, it's coming from the rocker cover, or weeping down from the intake end seals. Just a word of caution,,, oil on the headers is a real potential for a underhood fire. If worst comes to worst, get a bottle of the dye and a light to trace the source. __________________ Still playin with trucks, even at my age! When you're dead, it's only a problem for the people around you, because you don't know you're dead. .....It's kinda the same when your STUPID. I just did my taxes and reviewed my SS statement. Thanks to the current administration it looks like I will only have to work till noon on the day of my funeral.

08-12-2013, 08:08 AM	#5
Hertzdaddy Registered User Join Date: Oct 2008 Location: Montpelier, VA Posts: 315	Re: Oil leaking from #8 header tube? It sounds like you are saying its on the inside of the header. I had something similar when a exhaust valve seal went bad on a fresh install. I don't know why it went bad but it would either load up on the seated valve or oil down the piston after sitting for a while. Maybe check your plug and see if its burning any oil?

08-18-2013, 01:17 PM	#6
shortbed70 Registered User Join Date: Mar 2002 Location: Forney TX Posts: 4,512	Re: Oil leaking from #8 header tube? If it's on the flange and nothing from the outside it points to a ring not sealing or valve guide or seal bad letting oil by Posted via Mobile Device __________________ Troy 1965 Chevy Bagged,361 sbc,voodoo cam,1.5 full roller rockers,patriot 185cc vortec heads 2.02-1.60,vortec weiand polished intake,demon carb my truckhttp://67-72chevytrucks.com/vboard/s...d.php?t=332884 Big Red Dog build http://67-72chevytrucks.com/vboard/s...d.php?t=572274



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