scoostraw

Guys!

I need your opinions please. I had an exhaust leak start up front on my '95 6cyl SR5. Today I hooked a vacuum cleaner to the tailpipe and blew air in. I found the problem right away.

It is leaking at #5 where the header pipe bolts up. I put a socket on the manifold bolt and found that it turned easily. It was definitely not tight. But unfortunately I found that the reason it isn't tight is because it appears to have been stripped. The prior owner of this truck had an aftermarket exhaust installed, with headers - and whoever installed it at the dealer apparently screwed it up.

So my question is... what exactly am I looking at here? Is the solution in this case a heli-coil repair?

Or.... (???)

Thanks in advance. I removed the bolt completely for now. (The bolt looks fine)

scoostraw

Answering my own post here. I did find an old thread on this topic. The suggested solution was to go with a longer bolt, which I did.

It grabbed hold and I was able to tighten it up ok. I still have a tick, but it's improved. Tomorrow I will look at things further and check the other bolts. I'm afraid to over-tighten.

Does anyone happen to know the length of the stock bolt? The one I removed was only 25mm long. I replaced it with one 35mm long. And is it necessary to use a hardened bolt?

wyoming9

iTrader: (1)

being this has headers who can really say.

It would depend on just how thick the header flange is.

Then the stock manifolds used studs not bolts the stock studs look to be 46mm

scoostraw

Hey wyoming thanks for the reply.

The good news (I think) is that I can turn all 6 bolts. (One turns easy enough that it may be stripped as well) So I'm thinking the way to go is to maybe pull everything and replace the exhaust manifold gasket.

I've never worked with a header before, so I'm wondering if I would be able to move the #5 pipe away from the head enough to replace just that part of the gasket.

This is what it looks like:
The thickness of the gasket plus the header flange looks to be about 14mm. If the stock studs are 46mm as you say, I'm thinking of using 60mm length bolts (or something close to that). For some reason JBA supplies 25mm bolts with this header kit, which in my opinion are way too short.[/LEFT]

wyoming9

iTrader: (1)

My luck I would never be able to get away with just replacing part of a header gasket.

I am thinking you need the gaskets for those headers now I am going back quite a few years but each header company had there own gaskets

Then everyone made headers for Camaro`s Chevelle`s

scoostraw

Yeah that was my next question - are the gaskets "stock".

Can't tell from the photo online. I'll see if I can call them.

scoostraw

Hey! I called JBA and they told me it's a stock gasket.

So NAPA here I come...

scoostraw

Well I swapped out the gasket and.... no change...

So I'm guessing there must be some surface defect on either the header pipe or the head itself. When I replaced the gasket, the pipe did not move easily - so I moved it just enough to slip the new gasket in place. I did not get a good look at the mating surfaces.

So what do you do in a case like this? If I find a ding in the metal or something - what is the best approach to take?

wyoming9

iTrader: (1)

You did manage to get all the bolts or studs to pull in snug evenly

If you didn`t no matter what it is going to keep leaking .

Headers were a real pain on street vehicles the bolts always came loose from the thermal cycling .

Might be as simple as part of the old gasket still stuck on the head.

Then if you had a leak quite possible some metal has eroded away .

A trick from the old days was permatex # 2 it seemed to seal slight exhaust leaks

Malcolm99

Wyoming is spot on, if the manifold thread(s) is stripped you will never stop the manifold flange leak ever, you need to replace the Manifold and re-thread the aluminum head in order to fix the issue permanently. There is specific grade studs and nuts used for manifolds, not bolts as bolts tend to strip out before they grab enough thread to pull manifold tight to the head, whoever installed the header should have used manifold specific studs and nuts. You can machine the flange flat but that may make it thinner and pron to warping, so I would replace it with a cast manifold if it was me, and order OEM studs and nuts.

scoostraw

Thanks guys for the feedback.

Nothing is stripped fortunately. I used 35mm length graded shouldered bolts and they are quite a bit longer than the bolts that were in there (I think the shorter bolts came with the header kit). The new bolts are all most definitely tight.

When I unbolted the header pipe, I was only able to move it about 1/8" away from the head. I didn't feel like taking more of the exhaust apart, so I fished out the old gasket and slid in the new one. It looked to me like I didn't leave any pieces of the old gasket in there - but I guess now I'll find out for sure when I do this again. I talked to the guy at Napa who has experience with headers and he agreed with you wyoming that a little permatex can't hurt - especially since I don't want to remove the pipe and have it machined. He suggested Ultra Copper and said to let it sit 24 hours before running the engine.

He also said that a header gasket from the OEM manufacturer might work better than the stock gasket from Napa.

This is the first time I've messed with headers so I'm learning. When I unbolted this one, the pipe on the back (offending) cylinder sprung out of position. So it was (is) bolted up under some tension. I used a prybar to move it back in place so I could line up the holes and get the bolts started. The longer bolts did not give me much clearance - and one in particular was really difficult. Had to start it with a wrench and then when I could finally get a socket on it, it was one click at a time on the ratchet to tighten it up. What a pain in the @ss.

Anyway I have a gear-wrench coming of the size I need to use this time. And today I picked up one of those Lisle exhaust manifold spreaders. I have my permatex goop. So later this week I plan to go back in and hopefully fix it up.

scoostraw

Fixed!!

I unbolted the header again and this time I moved it as far away from the head as I could. It still was tight tho, and I really did not want to dis-assemble things further - so I applied a bead of permatex to the gasket on both sides, let it tack up a bit, and then re-assembled with the bolts just snug. The next morning I torqued it all down and fired it up. All quiet.

If it lasts the winter I'll be happy. Or if it lasts forever I'll be even happier. If it fails again, next time I'll remove the header pipe entirely and do a more proper repair.

Man what a relief to have things quiet. It was un-nerving to no end to have that ticking. And the gear-wrench made all the difference in removing and installing those bolts. I thought I was going to have to use an s-shaped wrench, but this worked perfectly.

Thanks again for the help guys.

wyoming9

iTrader: (1)

I am glad it worked

I would check the bolts again in a few hundred miles.

They tend to loosen and then the gaskets blows out again.

scoostraw

Yeah I'm carrying the tools with me. I'm gonna check them frequently.

When I road tested yesterday I was afraid to step on the gas too hard for fear I would blow it out again.