3.0 exhaust studs

[82heep7]

I have a 91 Path. 3.0 w/ (guess what?) 2 broken exhaust manifold studs. The 2 that are broken are the rear studs from ex. manifold to cyl. head. Any of you Nissan tech's have a suggestion on how to get these fn things out? Tryed to weld a bolt to them (alum head, steel stud) no luck. Tryed drilling and using an easyout, no luck there either. Next step, long LH drill bit 5/32 if I could find one? What have you had luck with? Thanks in advance, Kevin.

[McSoo]

Exhaust manifold studs SUCK in the 3.0's. I don't know anyone who hasn't had trouble with them. Aside from drilling them out yourself, all I can think of is taking it to a shop. :( And putting plenty of Antiseize on it for next time.

[KingTJ]

your going to have to drill out the stud and then use heli coils. My friend had to do the same thing to his.

[XJ]

I've been lucky... the rear left one unsrewed by itself... so I replace it by a brand new from a Nissan dealer to be sure to have a stud that is strong... result... the new stud broke in the head few months after... So I decided in a hapiness moment to let the stuk f**k alone broken in the head!! I just hope the other ones won't do the same... anyways for now my exauht leaks at the Y pipe cover for the sound of the manifold!!!

:flipoff2:

[camojunk]

There is no magic to it. I am a Nissan mechanic, and we do just what you have done, often ending in helicoil, some of the hacks here replaced heads because of too much fawkin with it. be careful and gentle so you don't damage the head, but I would say at this point you need to start drillin' and get the helicoils ready

[digorok]

What type of EZ out are you using???? I have found that the reverse screw type is not as good as the tapered square type. To me the screw in type makes it tighter by forcing the threads out. The square type kind of collapes the sides. I've almost always had better luck with the square type.
Just my experiance.

[fj40guy]

Better luck with the square sided ones.

Side note... get some LEFT HAND TWIST drill bits. Snap on carries them (at a premium). But I found the older "almost dull" one works best. As I start to drill, the stud heats up from the drilling. There is something so satisfying to see that sucker suddenly spin out on it's own! :D Hence the left hand twist. Heat and vibration seem to do the trick (about 50% of the time).

Another trick... use a dremel tool with that small "ball" tip. Just dimple the center of the bolt to get started, then drill.

Camojumk... I thought Nissan had "improved studs" on the 3.0??? Are the later ones larger? Or all of them 8mm. Oh, as to busting studs on the end of the exhaust manifold... seems to have started with the L28 (280Z) and always remained so ever since. That rear stud, and the two bolts on the bottom of the air box were always gone. :D

Desk job these days.

Tom :usa:

[digorok]

I got a set of left hand bits from a "licensed machanic" who got them from Snap-on. He told me the Snap-on guy told him they were guaranted to take out broken bolts. He tried them and told me they were all dull and junk. He was so mad me was going to throw them in the trash. I took them thinking he burnt them and I could sharpen them. After I got home I noticed they were left hand bits!!! Just goes to shows a license is no guarantee a machanic knows what he's doing. :p

[stanley]

My brother just had this done on his 90 3.0 Pathfinder. When he took it to the shop they said there was no easy way to do it. They said it could take anywhere from 30min to 4 hrs. Not sure how long it took them, but it ended up costing less than $100.

[digorok]

I did another broken stud removal. This one was a 1995 P/U, 4x4, passengers side rear. Had to drill it, took an hour and a half start to finish.
Sometimes, if your lucky, you can use a sharp punch to take the stud out. Just tap it in reverse. If your lucky it will come out.
For those who take it to a shop to do, make sure they replace all the studs and not just the broken one. Cheaper to pay for studs than pay for the whole job again. A good shop will insist you replace them all.

[denver d]

drill it ou and then put a 10mm x1.25 helicoil in the head. The bigger stud won't break nearly as fast. And, whatever you do take the time to replace all the studs. These fawkers have a tendency to be very brittle and love to break when you torque the nuts back down. Also have the manifold resurfaced not replaced like some dealers want you to. Your old manifold has had enough thermal cylcles to be less likely to warp again. If you don't fix this exhaust leak then you are going to be burning too much fuel- the incoming O2 fools the oxygen sensor that your truck is running lean.

[XterraGuy]

Friend was lucky, both broken studs on his '95 broke with a good 1/4" or more still sticking out of the block. Some locking pliers were all it took to crank 'em on out.
All the studs that came out were like new where they had been in the block, no rust/corrosion or anything. It was pretty remarkable.

[digorok]

I wonder why it is they brake all the time???? I notice that only Nissans seem to have this problem. Never had them brake on my Toyota p/u.

[ghettojeep]

I'm about to change the gaskets on a friends 90 Pathfinder, I'm guessing that this is something that I really have to look out for. I"m thinking soaking it in PB Blaster for about 24 hrs, then doing it. Should this be enough to loosen those bolts so it doesn't shear the stud, or is there more steps I should take. Since this isn't my truck I really don't want to fawk it up. Is there a good chance that I'm gonna break one? If the answer is yes, I might just tell him to bite the bullet and let a shop do it.

I also could just use a dremel and cut the bolts off first, fully or partially so they lose their grip on the stud then just replace them. Any advice?

[digorok]

Why do you need to change the gasket???? Is it leaking???? If it is you might have a broken stud already. It's not really that hard to remove a broken stud. It's just that you have so little room to work. If you take your time, and drill the hole straight you should not have a problem. Good luck

[ghettojeep]

No they're not leaking, its a performance upgrade, were gonna put in some high flow gaskets.:flipoff2:




















Of course they're leaking. But all the same I might pass on it, doesn't seem like its worth my time if I end up fawking them up. I've talked to a mechanic who is on a local board and he says that its a nasty, nasty job.

[digorok]

On the trucks it's not that bad of a job. Take the off the tire, fender splash shield, move some metal lines, remove the heat shield, and you can see everything. Try doing one on the firewall side of a Maxima, that's what you call hard.
If you've never drilled out a broken stud before, I would spend the money and send it out.
Being an old time racer, I've drilled out many. It's kind of an art. Even some machanics mess it up when they rush. Just take your time and drill straight.

[fj40guy]

Originally posted by digorok
. Just take your time and drill straight.

Yep.

One trick to "drilling straight" when you are first learning this. Find a mirror, put it right up to edge of the drill. If the drill and it's reflection are a straight line... you are dead on. Easy to tell with a mirror.

I've mentioned dimpling the back of a broken stud with a dremel tool. One thing I didn't mention... take your time and get it dead on center. If you are centered, and the reverse twist drill didn't do it's trick, I'm worked up in drill sizes a little a time... onlything left was the orignal threads!!! Then it is time for dental pick to bring them out. :)

On a Maxima... damn, getting too old to squeeze in there. Drop the engine & Tranny, then work on it. :)

WELDING ROD: Anyone ever use the special "flux coated rod". Idea was to fire up the arc welder, hit the road on the top of a broken bolt, and it would build up enough metal to grab onto, flux prevented any metal from sticking to the sides of the threaded hole. Never used it, too chicken, but remember seeing that stuff a few years back...

Tom :usa:

[XterraGuy]

Originally posted by digorok
I wonder why it is they brake all the time???? I notice that only Nissans seem to have this problem. Never had them brake on my Toyota p/u.

It's break, not brake, first time I've seen that before, usually people say break when they mean brake ;)

Anyway, it's the iron manifold on the aluminum head and the different expansion rates that put stress on the studs and break them.

As for dealing with them, there's not a damn thing you can do w/ PB or anything else to get the nuts off the heads apparently. My friend soaked his in PB and ended up taking the studs out of the block with the nuts still fused on them. Even re-used 'em all too except for the 2 that were broken.

Brent

[digorok]

Brake, break, everyone knows what I ment.
As for the welding rod trick, I've heard of guy's trying it. Sometimes it worked, sometimes not. I would thing with the limited space you might have trouble hitting the right spot. Maybe a MIG might work. Anyone ever try????

[unimogken]

On my 1991 Pathfinder I took it in to the shop and they said that the leaky manifold was under a recall. So during the work they did they broke off 5 studs and then tried to get them out then gave up and put some new heads on for me and tried to get me to pay for that.

Well I might of if they would of asked but they did it all w/o asking and that doesn't fly here.

[digorok]

Anyone know anything about this leaking manifold recall???? Never heard anything about it before.
A dealer ship that has machanics that can't drill out broken studs??? Sounds like a shop I would avoid.