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So, I took GB out to play one evening. I'm on a nice straight, flat, desolate strip of road out in the middle of nowhere. I stop the car. I rev the engine a few times, then floor it. The engine springs to life, the wheels start to spin, and then I hear it .... a "thunk" as something hits the undercarriage, another "thunk" as whatever it is hits the pavement, and at the same time, instant exhaust leak sound.

I say to myself, "Darn, the collector bolts loosened again, and one popped out."

Wrong!!

I only wish it were that simple.

What happened was a piece of the passenger side header blew out, and I had a quarter-sized hole in the top of one of my header pipes:

THE HOLE









The rest of the header is fine - no cracks or fissures or corrosion, and the driver's side header is fine.

I called Kooks to tell them and find out if there was any recourse. They told me to provide them with a picture and a copy of the original invoice, showing that I'm the original purchaser. Well, there was no way to get a picture until a bunch of stuff was removed from the top, or until the header was removed, so I started that process. In subsequent conversation with Kooks I found out that they no longer make the T-bird headers, they sold the flanges and jigs to another company. I also found out that they will "repair or replace" at their discretion, and they only warranty their stainless steel products, they don't warranty mild steel headers. They also do not re-coat the repaired or replacement headers - the costomer has to pay for that. The rep couldn't really tell me what would happen if a replacement was necessary, since Kooks no longer has the flanges or jigs. That question is moot, anyway, since my headers were made from mild steel and not under warranty (I don't think they offered them in stainless). I'm not complaining about Kooks, mind you, I'm fully aware that it's part of the game with a highly modified car - stuff just is what it is, and you gotta pay to play. I'm merely passing on information I learned.

So, what to do? what to do? Here's what I did:

THE PATCH







So, what caused such an unusual type of failure? My exhaust guy and I scratched our heads for awhile trying to figure out how it happened. Then we figured it out (we think).

The Culprit:



Yep, that's it. The evaporation drain from the air conditioner. I'm sure most of the guys with Kooks headers noticed that the A/C evaporation drips right on the headers. I know I noticed the periodic "hiss," figured out what it was, and, thinking only about rust potential, said to myself, "No problem, the water instantly turns to steam, and won't be on the tube long enough to rust it." I actually thought it was kinda cool (literally) that I could sit on line at the track with my A/C on, and no one would know or complain, 'cause no water ever leaked to the pavement.

What I failed to consider is that the process of evaporating the water cools the metal, if only for an instant, then the metal reheats (expands), then cools (contracts), then heats, etc. - over and over again, every time I run the A/C, which is most of the time in Florida. This constant expansion and contraction, only minute, but confined to this small, concentrated area must have caused stress fractures in the metal, and eventual failure. This explains why the failure is only on the passenger side, only in the one place, and would explain why the hole is nearly perfectly round. The evaporation water hits the tube and spreads out in a circle, only so far before it evaporates off the tube. Of course I'm not 100% sure, 'cause with the headers out, I can't really tell if the hole is in the exact spot where the evaporation hit, but it seems to be. At least that's all I could figure out, if someone has another explanation for the failure, feel free to chime in.

To prevent it from happening again, I'm gonna attach a 3/4 inch ID hose with a 90 degree bend to the evaporation drain and route the water elsewhere.

Removing the passenger side header from GB involved much "weeping and gnashing of teeth." With the aftermarket valve covers and all the intake plumbing, there is no way to get to any of the header bolts from the top. So, the front suspension had to come out along with the K-member, while we supported the motor from the top. Then, we had to raise and lower and tilt the motor from side to side, and remove the A/C dryer and variouse hoses to get to all of the header bolts. It did not help the removal that the bolts are Stage 8's, and they won't be easy to clip back in, but they are the only way to go.

If they haven't already done so, anyone with Kooks headers should consider re-routing that evaporation drip. Just sayin'

;)

-mike
 

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There is probably noting wrong with the material in the headers, but all know that you should not put water on hot steel. It may crack. Thanks for the information about the drain of the AC.

Berth
 

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There is probably noting wrong with the material in the headers

Berth
I would agree with that. I had the passenger side header in my hands and was able to inspect it carefully and I saw no other evidence of any potential failure. The metal we cut around the hole, was intact. Also, I have not heard of anyone else with any problems with the headers.

I will say, however, that the tubes appeared to be only 16 or 18 guage.

As for who is making the headers - someone should probably call Kooks and verify what I was told. I did not pursue the question. Here's the website:

Kooks

and the number I called was 1-866-586-KOOK (5665). They also have moved from Long Island to Statesville, NC.

-mike
 

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Still would like to see a pic of your painted and finished hood. :)
 

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Thanks for the heads up Mike. I'm sure no one wants to pull their headers...what a royal pain.

I guess I don't need to worry since I have no ac on my motor.
 

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Still would like to see a pic of your painted and finished hood.
So would I, but "aesthetic" projects are on hold for now. Maybe sometime after the first of the year I can get my paint guy to shoot the hood.

-mike
 

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There is probably noting wrong with the material in the headers, but all know that you should not put water on hot steel. It may crack. Thanks for the information about the drain of the AC.

Berth
:zwthstpd:

Hmmm I wonder if they were made from CHEAP China steel
Even the best steel will fatigue under the conditions described by GoldBird.
_________________________

Thanks for posting this info Goldbird. I'll be implementing the AC drain re-route that you described right away.
 

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Thanks for the heads up Mike. I'm sure no one wants to pull their headers...what a royal pain.

I guess I don't need to worry since I have no ac on my motor.
I bet it is a pain with the 4.6l in the way.....I tell you though, even with all the open room I have, it took me quite a few hours...err days to fit mine.
 

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Judging by the first picture, I have to disagree with your diagnosis. That first pic shows both the hole in the primary tube as well as the A/C drain on the dash, and you can see that the hole is a good 4-6" forward of the firewall. I have no idea what else might have caused it, but I really doubt the A/C drain had anything to do with it.
 

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Judging by the first picture, I have to disagree with your diagnosis. That first pic shows both the hole in the primary tube as well as the A/C drain on the dash, and you can see that the hole is a good 4-6" forward of the firewall.
Right you are, I didn't even see that. Due to the angle that the camera was at, I'm not sure the firewall is 6-8 inches from the hole, but it sure appears to be forward of the hole. The camera was not pointed straight down, so the perspective is scewed.

I'll know better tomorrow. The header will be re-installed and all the various hoses and cables, etc will be back in place, and I'll be able to see if it's at all possible that the evaporation either dripped directly on, or somehow traveled to that place. That the water hit the header somewhere is undeniable, exactly where it hit is the question, and I'll know more tomorrow.

Actually, someone out there with Kooks can run their car with the A/C on and see if they can find where the water hits and let everyone know.

Anyhow, wherever the evaporation hits the header, it's probably a good idea to re-route it. I did. I ran a hose through the chassis and the water will drip straight to the ground behind the front tire.

-mike
 

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jet-hot coating didnt help either?
 

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jet-hot coating didnt help either?
Assuming my theory is correct, and I'm not sure it is, it's the cooling process that stressed the metal, not the actual water hitting the metal. I'm thinking that when the water hit the tube, the coating lost heat to the water, the metal underneath lost heat to the coating, causing contraction, that would be the cooling process caused by evaporation. The coating may have slowed or mitigated the cooling somewhat, but ultimately if the water evaporates, the surface it hits will lose heat, and in turn, so will everything in contact with the surface losing heat. I mean, that's just the cooling process in general, material doesn't gain cool, it loses heat, and heat travels from hot material to cooler material. But that comes from someone with only an undergraduate degree in chemistry, I'm sure there's someone out there more qualified chemistry or physics or metallurgy than I that can explain or discredit the theory.

But all that aside, the Kooks rep I talked to said that in their experience, in general, coating is detrimental to the integrity of the metal of the headers. He explained to me that the coating holds the heat in the metal rather than letting it dissipate into the air. That causes the metal itself to become hotter than it would without the coating, and over-hot metal tends to crystalize and crack more often that cooler metal. He said they see more failures with coated headers than those without coating. In terms of heat, the coating is to keep heat out of the engine compartment, it is not for the benefit of the metal. That was his explanation, not mine. Again I'm just passing on information I was given by Kooks. Personally I feel that the coating has other benefits - appearance and it acts to slow down or eliminate external rust on mild steel.

Anyhow, I stopped by the shop this morning, and the good news is that barring any unforseen hitches, GB will be back on the road later this afternoon, and "terrorizing" the streets of S. Florida.

:diablo:

-mike
 

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I'd also have to dis-agree, the drip normally lands on the spot where the tubes connect and even if it was reciving a daliy drip you would see the witness mark. Looks like a bullet hole to me.

BTW, Your welder needs to go back to welding skool!

-Scott
 

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I'd also have to dis-agree, the drip normally lands on the spot where the tubes connect and even if it was reciving a daliy drip you would see the witness mark.
I'm sure you're right, but I can't check it 'til it's back together. I knew the water hit the header somewhere. There are no other marks anywhere on the header, and with it in my hands, I couldn't really tell where the hole lined up in relation to the firewall....

.... and it was the only explanation I could come up with given the shape of the hole and the fact that there was no corrosion or cracks anywhere around the hole, or anywhere else.

Looks like a bullet hole to me.
Now that explanation never occurred to me. There's no corresponding hole in the top of the hood, though :confused:

BTW, Your welder needs to go back to welding skool!

-Scott
... and you need to go back to skool school... :)

Yeah, he's been welding exhausts for 30 years, he may have forgotton a few things from school. At this point, my ONLY concern is that it doesn't leak, and the patch doesn't pop off, and it looks like he's got that pretty much covered. As for how it looks, it's not in a real easy place to get a grinder. It's not in an easy place to get the welder, for that matter. It's not like he had much choice in his "angle of attack." There's scarcely 1/16 of an inch between the tubes on the top back of the patch on the collector side and the tubes above block him from coming from the back, left or top. I had to look from under the car with a mirror to see the hole when the car was all put together. I couldn't get flashlight beam on it, or take a picture of it from the top. I think it'll be just about as hard to see the patch when it's done.

Anyway, like I said, how it looks is far less important to me than how it works and how it lasts. I Don't ever want to have to do this again.

One good thing that came from all of this is that we're taking this opportunity to go through the A/C hoses and try to plug up the leaks and re-charge it. It may be December, but it's still bloody hot down here...

Next step, rear tires and an aligment.

:cool:

-mike
 

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and a diffy rebuild
 

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Mine drips here,and I don't think that caused your hole. I honestly don't think the A/C condensate will cause any issues like this.
JL
 
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