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leak from exhaust manifold
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biohazard
User
Sep 8, 2013, 8:40 PM
Post #1 of 28
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leak from exhaust manifold
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I have a very strange leak from the exhaust manifold right at the head. its more of a seep than a leak. I have made sure that its not leaking from the valve cover. can't really tell if its gas or oil. I don't know much about piston engines so I'd really like to hear any advice anyone might have on fixing this. its on a 1991 chevy c1500 v6 4.3l
[url=http://postimg.org/image/wf6b91yn5/]
(This post was edited by biohazard on Sep 8, 2013, 9:42 PM)
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Hammer Time
Ultimate Carjunky
/ Moderator
Sep 9, 2013, 2:55 AM
Post #2 of 28
(3684 views)
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Re: leak from exhaust manifold
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Of course it's coming from the valve cover. There is no liquid oil in the exhaust system
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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GC
User
Sep 9, 2013, 6:20 AM
Post #3 of 28
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Re: leak from exhaust manifold
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Is that cylinder firing properly? Does the engine feel like it is misfiring? Have you noticed excessive moisture in exhaust?
____________________________________________________
Willing to help, willing to learn... Rob
(This post was edited by goiserclause on Sep 9, 2013, 6:25 AM)
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biohazard
User
Sep 9, 2013, 3:36 PM
Post #4 of 28
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Re: leak from exhaust manifold
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i havent noticed any excessive moisture in the exhuast. i park in a clean street its not dripping any fluid of anykind. but i am loosing oil just dont know where its going.
i went to check out my spark plugs and wires. when i pulled off a wire it came apart leaving the connector on the plug. so im going to replace all my plug wires. i decided to crank over the engine with the plug wire off. there dosent seem to be any change other than a loud click noise. i used a mechanic stethoscope to isolate the noise.
[url=http://postimg.org/image/v9wpyb9yv/]
this seems to be making noise now. even after i replaced the wire with a new one. i have no idea what this thing is but it sure is ticking pretty loud.
so if the plug is bad then will oil/gas seep through where the exhuast minifold and head meet?
(This post was edited by biohazard on Sep 9, 2013, 3:49 PM)
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Sep 9, 2013, 5:24 PM
Post #6 of 28
(3643 views)
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Re: leak from exhaust manifold
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No comment.......... T
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biohazard
User
Sep 9, 2013, 9:01 PM
Post #7 of 28
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Re: leak from exhaust manifold
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i seen it was connected to the dist. so i didnt touch it directly with the steth. its a pretty loud tick. i put it the intake and valve cover then leaned over and used my ear. so its the dist coil then awesome. i came to this forum to seek help i can take insults and all where i deserve them but im looking for help with my leak. is there anyway or reason why oil would leak out of the head right there?
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Hammer Time
Ultimate Carjunky
/ Moderator
Sep 10, 2013, 3:13 AM
Post #8 of 28
(3623 views)
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Re: leak from exhaust manifold
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Again, that oil is not coming out of the exhaust. The stain you see came from the valve cover. Oil doesn't run uphill.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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Discretesignals
Ultimate Carjunky
/ Moderator
Sep 10, 2013, 4:29 AM
Post #9 of 28
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Re: leak from exhaust manifold
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Using your ear against it is even worse. You do realize that the voltage from a good coil can jump up to 2 inches or more. The spark is looking for ground and your ear or stethoscope would make an excellent path to it. I've never been dumb enough to get smacked in the ear by an ignition system, but I can imagine it would hurt like hell.
Another thing is never ever run a coil open circuited. The secondary voltage has no where to go, so it is going to look for ground. It probably popped a hole through the case because you ran it without the plug wire installed and that is the clicking noise your hearing. Always provide a path for the secondary voltage to get to ground when pulling plug wires.
Your dealing with high voltage, so you need to take some precautions that you're obviously ignorant about.
I'm glad that your insulted, because maybe you'll remember what was typed here.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
(This post was edited by Discretesignals on Sep 10, 2013, 4:38 AM)
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biohazard
User
Sep 11, 2013, 5:13 PM
Post #10 of 28
(3599 views)
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Re: leak from exhaust manifold
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thank for your education on dist coils. i will remember thats for sure. i did not know that running it with an open plug wire would hurt it.
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biohazard
User
Sep 11, 2013, 5:23 PM
Post #11 of 28
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Re: leak from exhaust manifold
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i am 100% sure the oil is not coming from anywhere on the vale cover. i have cleaned all around where the valve cover meets the head and cleaned around the exhaust manifold where the oils is. let it idle for 30mins drove it about five miles on the highway and no oil is coming out from the valve cover. i even used a mirror and lights to inspect the very rear of the cover to be sure it wasn't running from the rear to the front and dripping down. but there was new oil around the exhaust manifold.
i cant make sense of this....
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Discretesignals
Ultimate Carjunky
/ Moderator
Sep 11, 2013, 5:28 PM
Post #12 of 28
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Re: leak from exhaust manifold
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It's alright....atleast you didn't learn the hard way.
Open circuiting a coil is like putting a fat guy on a treadmill going full speed. The spark is going to find the easiest way to ground even if that means burning a hole through the coil housing.
If you really want to see if the plug wires or coil is leaking spark externally, wait till night time. Take a 12 volt test light with you and connect it to the battery negative. With the engine running run the test light around the coil, wires, boots. You'll see sparks jumping to your test light probe if you have a leak. If you hear snapping from the coil, the coil is faulty.
You may see an aura or glow around plug wires when it is dark, but that is completely normal.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
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biohazard
User
Sep 11, 2013, 5:47 PM
Post #13 of 28
(3588 views)
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Re: leak from exhaust manifold
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i went ahead and replaced the coil and all the plug wires and tested each wire with a timing light they all seem to work.
the strange leak is whats really eating at me.
(This post was edited by biohazard on Sep 11, 2013, 5:48 PM)
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Hammer Time
Ultimate Carjunky
/ Moderator
Sep 11, 2013, 5:58 PM
Post #14 of 28
(3580 views)
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Re: leak from exhaust manifold
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It's going to keep on eating you if you keep looking for oil coming out of an exhaust manifold. Liquid oil cannot survive that temperature.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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biohazard
User
Sep 11, 2013, 6:01 PM
Post #15 of 28
(3577 views)
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Re: leak from exhaust manifold
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could it be leaking from the head and being pushed into the manifold and the pressure from the exhaust fumes push it out between the manifold and head?
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Hammer Time
Ultimate Carjunky
/ Moderator
Sep 11, 2013, 6:04 PM
Post #16 of 28
(3573 views)
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Re: leak from exhaust manifold
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I'll explain this one more time. Oil does not run uphill. It flows downhill, meaning if you find it between the valve cover and the exhaust manifold, it came from the valve cover.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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biohazard
User
Sep 11, 2013, 6:15 PM
Post #17 of 28
(3570 views)
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Re: leak from exhaust manifold
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its not a flowing or dripping leak. its a very gradual slow slow seep. and i have looked and looked and looked again at the valve cover seal. after driving it i run a new white rag with my finger around the valve seal and cant pick up any new oil but its still down by the manifold. there is no line that runs down from the cover to the manifold.
in the first pic i posted you can see the oil around the exhaust i believe it crept up through the dirt that is there.
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Hammer Time
Ultimate Carjunky
/ Moderator
Sep 11, 2013, 6:17 PM
Post #18 of 28
(3566 views)
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Re: leak from exhaust manifold
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It doesn't look wet to me. are you sure it's not just exhaust soot?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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biohazard
User
Sep 11, 2013, 6:27 PM
Post #19 of 28
(3564 views)
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Re: leak from exhaust manifold
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im positive its wet. when i bought the truck there was no stain there.after putting 20 miles on it or so i noticed the dark spot. it was only about a 1/4 inch or so around the manifold. thought to my self..was that there before. i took a mental note. then after driving it more a noticed the spot grew . now it was about 1/2 inch around the manifold. after realizing its growing slowy but surly to what it looks like now.
wich looks a lot like a cover leak. that is why i have thoroughly checked this before i go replacing the cover gasket.
oh yeah and im slowly loosing oil. but idk where its going sence there no drips in the street
(This post was edited by biohazard on Sep 11, 2013, 6:28 PM)
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Hammer Time
Ultimate Carjunky
/ Moderator
Sep 11, 2013, 6:37 PM
Post #20 of 28
(3552 views)
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Re: leak from exhaust manifold
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I don't know what to tell you. If that cylinder is firing and working normally the temperature can reach 2500 degrees and oil will turn to ash at that temp.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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biohazard
User
Sep 11, 2013, 6:44 PM
Post #21 of 28
(3549 views)
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Re: leak from exhaust manifold
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the plugs i pulled looked like they were getting too hot. i have read other forums and articles that say it could be leaking from behind the bolt that holds the manifold in place.
i havent checked this yet. or a cracked head?
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Discretesignals
Ultimate Carjunky
/ Moderator
Sep 11, 2013, 6:45 PM
Post #22 of 28
(3545 views)
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Re: leak from exhaust manifold
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Looks like valve cover gasket to me. You would hear an exhaust leak if it was somehow magically leaking oil from between the manifold and cylinder head.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
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biohazard
User
Sep 11, 2013, 6:52 PM
Post #23 of 28
(3542 views)
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Re: leak from exhaust manifold
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when im driving down the road i can hear what sounds like an exhaust leak. but it dose not make this noise when at idle. i can gas it at idle and it makes the exhaust leak noise for about half a sec then goes away with high rps but only at idle it goes away. with the engine under load i hear the putting noise of an exhaust leak. its very hard to pinpoit when im doing this myself. i was going to change the flange gasket where the manifold meets the pipe and see if that would get rid of the noise but i dont think that it will.it dosent sound like its coming from under where the flange gasket is but sounds like its coming from the hood
(This post was edited by biohazard on Sep 11, 2013, 6:56 PM)
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Discretesignals
Ultimate Carjunky
/ Moderator
Sep 11, 2013, 6:56 PM
Post #24 of 28
(3536 views)
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Re: leak from exhaust manifold
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With the engine running, take a rag in your hand and put it over the exhaust pipe. This puts back pressure in the exhaust system. Have someone listen for leaks.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
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Hammer Time
Ultimate Carjunky
/ Moderator
Sep 11, 2013, 6:58 PM
Post #25 of 28
(3534 views)
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Re: leak from exhaust manifold
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If you're so convinced that it is the exhaust gasket, then just change the damn gasket and be done with it. Why debate it here?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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