Leaking exhaust @ manifold

[Mscurfield]

Hello everyone, I'm actualy posting for my sister as she needs some help with her 2003 MSP. The problem is the exhaust mainfold keeps leaking, and there are no cracks in the manifold. It seems like the bolts keep coming loose some how. She has had this problem fixed by the dealer under warrenty twice by them replacing the exhaust manifold gasket and she has had to pay out of her pocket once as well so thats been chaged 3 times in total. Now its leaking again Is there a design flaw with the bolts? Has anyone replaced the bolts with Studs and nuts? If you have, how well did it work and do you have anymore info on the sizes and such that are needed. Also the exhaust manifold gasket that was used are the OEM gasket. I did search but didn't come up with much direct info on the bolts or OEM gaskets.
Thanks in advance for any info you can provide
Cheers MikeS

 

[SeR_Cyclops]

I have never heard of this problem. Were they tightened correctly?

 

[MAZDA_SPEED]

Maybe they striped the threads.

 

[CHIQLES]

+1 on the threads your mani is probably warped. I know mine is and even after torqueing if you dont have the right hardware they will come loose, I intend to switch from bolts to stud and nut combo from crossover auto. that should help me and most likely you.

 

[Mscurfield]

Thanks for the help guys. Yeah everything was torqued down propperly but I dont know 100% if they did check to see if the manifold was warped. I'll make sure to get that checked when I replace the gasket again.

I did recive a PM from a member giving me some info on the stud and nut convertion so I will look into that further. I dont know how quickly we will be getting the new gasket installed as its probably going to snow in the next couple days here and then the car goes into storage. I'll keep you posted when we do get around to it. I'll also check back to see if anyone else has any suggestions.

Cheers MikeS

I found that Crossover Auto performance has an ARP exhaust manifold Stud and nut set. Going to email them to find out more info.

 

[jdwk]

Any more info on the studs? My bolts keep coming loose on me as well. Judging by the very noticeable ticking noise when cold to dead silence once warmed up, I would say it's just the expanding and contracting that causes the bolts to wiggle out. I highly doubt it's warped.

 

[SeR_Cyclops]

Get some APR exhaust studs and see if that fixes your problem.

 

[jdwk]

Ouch, $99 on Crossover Auto. ARP has to be making a killing on these sets. The head kit for my C6 is over $200.

I think I'll just torque em down every six months. Takes 10 minutes, so at $50 an hour for my time, I would take six years to make up the cost of those studs.

 

[MAZDA_SPEED]

Just dont tighten to hard, you might end up striping them.

 

[SeR_Cyclops]

Yeah, and if one brakes in the block you will be like s***. Why didnt I just get those studs.... If you dont like those have a machine shop make you some out of hard steel.

 

[MAZDA_SPEED]

The manifold screws "shouldn't" come loose every six months. Its not normal.

 

[ASmitty]

I ran into the exact same problem.

1. Inspect the two studs, bolts and manifold
2. Order replacement hardware
3. Install replacement hardware with thread lock
4. ???
5. Profit

Doesnt hurt also to change out the gasket too, but in all reality, it's most likely fine.

 

[ASmitty]

Also to all the people who have never seen this before, There are multiple threads on the forums here about loose/missing exhaust manifold bolts. I was straight up missing one all together and another one was cracked in half due to manifold stress.

TO OP, about 40 bucks for factory replacement hardware from the dealer.

 

[SeR_Cyclops]

Yeah, I have heard of a few people having problems. That is why I think you should just get the upgraded studs.

 

[sephiroth]

Yeah, I have heard of a few people having problems. That is why I think you should just get the upgraded studs.

I would check the head/manifold matting surfaces before spending $$$ on studs, if the dealer wasn't cleaning the excess gasket material off or there are slight uneven surfaces it would better explain the issue.

I think I'll just torque em down every six months. Takes 10 minutes, so at $50 an hour for my time, I would take six years to make up the cost of those studs.

or you could head over to napa and get some copper lock nuts and never have to torque them again. I don't believe the OEM nuts are of the metal locking type, which is why people have problems so often. If they are they shouldn't be used more than once, which could also contribute to the repeated problem.

 

[SeR_Cyclops]

Well thats a given. If you take off the old manifold you are going to clean the surface a little. If you dont have a rolex pad on a angle grinder at least use like one of those 3m brown scuff pads.

 

[sephiroth]

Well thats a given. If you take off the old manifold you are going to clean the surface a little. If you dont have a rolex pad on a angle grinder at least use like one of those 3m brown scuff pads.

something we take for granted might not strike a dealer warranty repair tech that's just trying to get it done so he can start the next job.

 

[SeR_Cyclops]

That is true. If I were him I would Unbolt the manifold from the car and clean the surface if he does not want to buy new studs. AFter that if it still keeps doing it get new studs.

 

[jdwk]

So a little update. I ended up just buying two new bolts from Mazda. $6 each. Retarded, but a lot cheaper than studs. BTW, two of the fasteners on my manifold already are studs, not sure if that is original or not.
As expected, the top right (driver's side) bolt was loose again as expected. I replaced it with a new one and used the tq wrench to 16 lb-ft. But then I go to put in the bolt below it and there is still a bolt in there. Guess the previous owner of the car (or I wouldn't put it past a Mazda tech), popped the head right off.
So, I guess I am stuck tightening down the top bolt every year, because I know it won't be cheap to go get that guy extracted.
There are some things you just can't check for when you buy a used car.

 

[gangstagangsta]

To the OP, I had this same issue for a long time and could never figure out why. Everytime I would check my exhaust mani the bolts on the passenger side would be loose, broken, or missing completely. I changed my front motor mount last year and I have not had an issue since!