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Flames coming from exhaust manifold... by FieroCat
Started on: 12-15-2014 07:26 PM
Replies: 13 (318 views)
Last post by: 85 SE VIN 9 on 12-16-2014 08:33 PM
FieroCat
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Report this Post12-15-2014 07:26 PM Click Here to See the Profile for FieroCatSend a Private Message to FieroCatEdit/Delete MessageReply w/QuoteDirect Link to This Post
I was already pretty sure that my forward exhaust manifold on my V6 engine had a crack due to the loud ticking, but I inspected the engine while it was running in the dark tonight, and I could definitely see a lovely blue flame showing around the manifold in question as it ran. Right by the coolant tube that comes down from the thermostat on the passenger side.

I'm already set to get the manifold replaced, however what worries me now is whether or not it will even be safe to drive the 10 miles to the shop. Has anyone had major problems result from driving with this occurring? I have run the engine for a while with this happening apparently, but I don't know if I even want to drive it one more mile this way. Could this start a fire?

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My Fiero: 1986 Pontiac Fiero GT, V6, 4-speed manual

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Report this Post12-15-2014 07:30 PM Click Here to See the Profile for olejoedadClick Here to Email olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post
You've driven it how many miles in that condition?
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FieroCat
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Report this Post12-15-2014 07:37 PM Click Here to See the Profile for FieroCatSend a Private Message to FieroCatEdit/Delete MessageReply w/QuoteDirect Link to This Post
More than I'm aware of, probably. The tick has been occuring for about a month, though luckily this isn't a daily driver so not a lot of miles. My guess is that if there's anything there that it could burn through and affect, it would have done so by now. But the tick is sounding a bit louder, so the shop is the very next place it's going.

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My Fiero: 1986 Pontiac Fiero GT, V6, 4-speed manual

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Paul.S
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Report this Post12-15-2014 08:10 PM Click Here to See the Profile for Paul.SSend a Private Message to Paul.SEdit/Delete MessageReply w/QuoteDirect Link to This Post
If it were me, I would cut up an aluminum can to shield anything heat sensitive, and a steel one for the manifold. If you can't cover the flames completely, dissipating them some should be good enough for a 10 mile dive. -Paul

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1988 Fiero Formula 25k miles, garaged since 1988

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FieroCat
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Report this Post12-15-2014 08:14 PM Click Here to See the Profile for FieroCatSend a Private Message to FieroCatEdit/Delete MessageReply w/QuoteDirect Link to This Post
That's a good idea. I just wish it was easier to get back there... can't even see much of the area. But I think I can see the part of the manifold where the flame is emerging so the shield idea is doable.

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My Fiero: 1986 Pontiac Fiero GT, V6, 4-speed manual

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FieroCat
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Report this Post12-15-2014 08:33 PM Click Here to See the Profile for FieroCatSend a Private Message to FieroCatEdit/Delete MessageReply w/QuoteDirect Link to This Post
Does anyone have a pic of the forward side of a removed V6 engine and what is around that area?

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My Fiero: 1986 Pontiac Fiero GT, V6, 4-speed manual

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Paul.S
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Report this Post12-15-2014 09:03 PM Click Here to See the Profile for Paul.SSend a Private Message to Paul.SEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by FieroCat:

I just wish it was easier to get back there... can't even see much of the area. But I think I can see the part of the manifold where the flame is emerging so the shield idea is doable.

I missed the word “forward” in your first post. I feel for you, my knuckles are still healing from my last plug change. You might be able to just bend up a can and shove it between the manifold and firewall. I was amazed how much easier it was to pull the rear deck lid (by myself) than to squeeze around it. it's like taking the lid off a big bin. Make sure you hinge restraining straps are in good shape or the mounts will go right through the rear window. -Paul

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1988 Fiero Formula 25k miles, garaged since 1988

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FieroCat
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Report this Post12-15-2014 10:14 PM Click Here to See the Profile for FieroCatSend a Private Message to FieroCatEdit/Delete MessageReply w/QuoteDirect Link to This Post
Ah yes, it is in the treacherous forward section of the V6. The only thing I can really see that it might be flaming on is the metal coolant pipe that bends around the manifold area. I guess that gets pretty hot anyway.

I'll poke around and fancy a shield somehow.

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My Fiero: 1986 Pontiac Fiero GT, V6, 4-speed manual

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Paul.S
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Report this Post12-15-2014 11:45 PM Click Here to See the Profile for Paul.SSend a Private Message to Paul.SEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by FieroCat:

The only thing I can really see that it might be flaming on is the metal coolant pipe that bends around the manifold area.

Get a good view, maybe a mirror or a better angle. If that is all it is you have nothing to worry about on a 10 mi trip, that pipe is full of coolant. The flame may have scary high temps but it's the liquid in that pipe that will control the temperature. Temps get way higher in the combustion chamber and the same coolant keeps all that under control. No way a little flame is going to overheat metal cooled like that. -Paul


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1988 Fiero Formula 25k miles, garaged since 1988

[This message has been edited by Paul.S (edited 12-16-2014).]

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olejoedad
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Report this Post12-16-2014 07:43 AM Click Here to See the Profile for olejoedadClick Here to Email olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post
Just drive it to the shop.
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FieroCat
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Report this Post12-16-2014 11:27 AM Click Here to See the Profile for FieroCatSend a Private Message to FieroCatEdit/Delete MessageReply w/QuoteDirect Link to This Post
Yep, will just drive it there.

Felt around the heat shield a bit this morning and noticed that it was separated from the manifold, looked like the bolts have popped out of the manifold that hold the heat shield onto it. I couldn't actually feel a crack in the manifold anywhere.

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Report this Post12-16-2014 11:43 AM Click Here to See the Profile for ZeakSend a Private Message to ZeakEdit/Delete MessageReply w/QuoteDirect Link to This Post
I found an old thread that has some 2.8 pics at the top.
Click

I wanted to ask if your deck lid has the seal that closes the gap to the firewall....
Mine was missing and I had a lot of heavy rust thanks to rain dripping on a hot exhaust.
(cat had a huge hole in the top)
Good luck!
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FieroCat
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Report this Post12-16-2014 11:59 AM Click Here to See the Profile for FieroCatSend a Private Message to FieroCatEdit/Delete MessageReply w/QuoteDirect Link to This Post
I do have the seal. It doesn't stop water from dripping when the deck is opened, however.

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My Fiero: 1986 Pontiac Fiero GT, V6, 4-speed manual

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85 SE VIN 9
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Report this Post12-16-2014 08:33 PM Click Here to See the Profile for 85 SE VIN 9Click Here to Email 85 SE VIN 9Send a Private Message to 85 SE VIN 9Edit/Delete MessageReply w/QuoteDirect Link to This Post
Don't psych yourself out. Of course it's not good, but more than likely many of us are driving with this problem and have been for years. I think the cracked manifold problem is more often the loose manifold problem. I've been trying to tighten mine up, but aside from the difficulty getting at them the problem with the bolts is they don't stay tight. I have yet to encounter broken manifold bolts, but I'm missing at least two.

The way you get broken bolts is likely related. The torque is only supposed to be 18 ft-lbs, not very much at all. People probably torque too much, then the heat breaks, or at least weakens, the bolt or stud. Or people just try to tighten too much.

Taking the manifold off and replacing the gasket is likely the correct solution, but careful repeated tightening will likely do the trick for a reasonable price. You can reach some of the bolts from underneath with a really long extension or from the top with a small wrench. One of the biggest problems I've been having is the sockets not coming off once you get the bolt tight. I've lost at least two sockets that way already. Still, this is a DIY project IMHO. Good luck and happy holidays!
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