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Bubbling coming from Exhaust Header - 92 RRC 3.9 V8

1059 Views 8 Replies 5 Participants Last post by  Mikieman
I am trying to fully diagnose an issue I'm having on my RRC. I will try to also post a video of what I'm seeing so it might make more sense. On cold startup, I have noticed there is a distinct bubbling of some moisture coming from cylinder #4 out of the space between the cylinder head and the exhaust manifold. The bubbling look like saliva and doesn't appear to be oil.
I am fairly confident that I at least have a bad gasket there as you can see exhaust escaping from #4 and #8 at the header gasket. Also, my rover gauge software shows lower lambda readings on the even bank and there is a loud sound that sounds like rod knock (but I'm hoping is just this exhaust leak).
I have a line on some cheap Hedman Headers anyway if this turns out to be a cracked header and not just a bad gasket. I'm wondering if the bubbling could be something more serious such as a cracked head or something.

A little background:
The head gaskets were done 2 years ago and the truck does not get driven regularly. I've been chasing various EFI issues since I've owned this thing for the last 3 years and recently had the whole upper intake off to clean out all the mess the PCV leaves behind. It runs OK for the most part except for an eternal CEL (code 48 stepper) that nothing will fix, and this noise that I hope is just a header leak. I used metal gaskets on the headers when I did my head gasket job.

Any ideas would be appreciated or if anyone has seen anything like this before.

I will try to post a video later today.
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Here is a clip of the issue at hand.
Well between filming your fingers and the earth quake you were experiencing. I couldn't see much. :lol:

It looks you have a heck valve cover leak.do you have a cracked exhaust manifold?

Are you talking about the little round thing? If so can you get a steady shot of just that?
Well between filming your fingers and the earth quake you were experiencing. I couldn't see much. <img src="http://www.rangerovers.net/forum/images/smilies/icon_lol.gif" border="0" alt="" title="" class="inlineimg" />

It looks you have a heck valve cover leak.do you have a cracked exhaust manifold?

Are you talking about the little round thing? If so can you get a steady shot of just that?
Haha fair enough, I was trying to also film the smoke coming out but you can’t see that as well.
Here is a clearer shot of just the bubbling.

Did you use any RTV on the head or valve cover gaskets when you replaced them? It could be as simple as some RTV expanding and melting, and then pooling on top of the exhaust manifold.
A compression test on the even bank cylinders will tell you if you have a problem with the head or head gasket.
If the compression test reads all good and you didn't use RTV or other compounds on the gaskets, the next step would be removing the exhaust manifold.
As an FYI if you haven't removed the exhaust manifold before, 25+ years of extreme temperature cycles will more or less fuse the bolts in place. Soak the bolts going into the head and exhaust downpipe with PB Blaster and let sit overnight. I broke a bolt off in the cylinder head and all three from the downpipe to the manifold when I replaced both cylinder heads earlier this year, and had to ream and tap new holes.
When I did the head gaskets a few years ago, I did not use any RTV or gasket makers, just regular composite head gaskets and metal exhaust manifold gaskets. I can perform a compression test to rule out any issues, but I recently had the truck in the shop trying to solve this insane Lucas EFI nonsense. They did a compression test and said everything came back even. The engine doesn't use any water and I don't see any green underneath when its parked. Like I said, it doesn't get driven too much so my testing isn't super accurate.
does it happen immediately upon cold start up and as the engine warms it goes away?, if restarted after warm up, does it repeat or does/has it ceased?
more than likely you have a bit of exhaust leak, possible due to improperly seated manifold gasket or slightly loose bolt. then you have cylinder condensation during initial cold start up. it is this condensation which bubbles, it happens on all cold engine start ups and only noticeable before metals expand and seal. sometimes you have that misterius exhaust leak noise which goes away minutes after start up but cannot be found.
all completely normal specially with current cold trends. you could try warming engine and re-tighten exhaust manifold to head bolts, they may turn about 1/2 turn and solve concern.
steel bolts loosen when used in aluminum due to different expansion and contraction rates of metals, reason all aluminum engines develop leaking/failure of head gaskets. nature of the beast.
I went out last night and tightened all the bolts on the even bank while the engine was still cold. Most didn't move, but a few on the offending cylinders had a few ratchet clicks to give. The bubbling was reduced after I started it up but the noise was still there. It doesn't go away as the engine heats up.
The noise is more noticeable from inside the cabin than standing next to the engine, and more prominent when the truck is in gear than when in neutral.
I bought a mechanics stethoscope which should be here today so I can pinpoint exactly where its coming from. I really hope its not rod knock, from what I've read that is fairly rare on these engines. The noise sounds like a diesel truck engine.

It would just be my luck on this car that I would need a new engine.
To me the noise sounds like a exhaust leak
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