Bank 2 exhaust manifold on 1MZFE V6

Status
Not open for further replies.
Joined
Dec 2, 2005
Messages
1,465
Location
Kennett Square, PA
Well, I totally butchered removing the Bank 2 A/F sensor on my 99 Avy. Replaced the less accessible Bank 1 twice without problems but Bank 2 is original and it seems like it is welded in there. Anyhow, the only chance I have at this point is to remove the exhaust manifold to get better access. Fortunately there is a flange separating the manifold from the exhaust. This flange has studs with what appears to be male Torx ends. Looks like you remove the nuts on the exhaust side and then unscrew the studs. The studs screw Into the flange on the engine side. I believe you have to remove the studs in order to have enough play to remove the manifold but I could be wrong. When you remove the 5 nuts holding the manifold onto the engine, I do not think you have enough play to pull it away from the engine far enough to clear the engine studs unless you have the flange studs removed.

Has anyone ever removd the exhaust manifold on a 3.0 V6 1 MZFE engine? Any tips? Thanks.
 
Last edited:
You've tried heating with a MAPP gas torch?

Kroil or 50/50 ATF and Acetone?

02 socket on a 1/2 breaker bar?

Thread cleaning tool on hand?

Pulling the manifold is a last resort, because I fear the concept of touching rusty manifold studs (Owning a Nissan VG will do that to you
mad.gif
)
 
assuming you can get a drill in there. I would drill it out then tap the remains toward the center of the 1/2" hole you created
 
Originally Posted By: HerrStig
Best start looking for a used manifold.


Not for me. I don't want someone else's junk, especially on an exhaust manifold with a pre-cat.
 
Thanks for the responses. The manifold did come out with some persuasion after removing two support brackets which allowed the exhaust to drop 1/2" or so. When reinstalling I will definitely install new flange studs AFTER the manifold is tight against the head. Getting the nuts off the head studs was not nearly as difficult as I expected. With the manifold out, I had full access to go after the remains of the A/F sensor. No freaking way. The only option left is to weld on a nut and try again. Not sure if I want to go for that as a brand new OEM manifold is less than $250. Plus I have to get the studs out of the old manifold which is not going to be easy. This old girl owes me nothing. Been trouble free with me doing all repairs. I don't mind spending a little to get her right again
 
Ok, I could not stand being defeated! I cut off the af sensor flush with the boss and drilled it out with a 3/8 bit which was the largest one I had. Made 4 axial cuts and drove the segments inwards breaking them away from the manifold. Took a lot of finagling but was able to remove it in pieces. Threads are badly buggered at the entrance and I could not get my thread chaser started square. Figure the cost of having threads professionally chased will be peanuts compared to the $250 for a new manifold. My wife thinks I am totally bonkers but dedicated DIYer's never give up.
 
Originally Posted By: artbuc
Has anyone ever removd the exhaust manifold on a 3.0 V6 1 MZFE engine? Any tips? Thanks.


The best thing to do when removing the sensors, is to have the engine hot on the day you are removing the sensors. Let the engine cool for about 20 mins and make sure you are using heavy duty gloves while you remove the sensor.

I have replaced the exhaust on my 98 Sienna on the same engine. Front A/F sensor was easy to change. Those studs on the manifold strip out easily. Did you try to remove the nuts and lower the exhaust first? Also those nuts that hold the exhaust are a one use only.

Sounds like you got the results you needed. Hope you used anti-seize on the threads in case you need to make the same repair later on.
 
Originally Posted By: JC1
Those studs on the manifold strip out easily. Did you try to remove the nuts and lower the exhaust first? Also those nuts that hold the exhaust are a one use only.


I would never attempt to remove the studs in the head. I just removed the nuts. Yes, I removed two support brackets and the exhaust dropped enough. After I had the manifold out, I removed the studs in the flange connecting the manifold to the downstream exhaust to facilitate reinstallation. The nuts on those studs have a split in them so I am guessing they are the ones you say are one use? The 6 nuts on the manifold to head studs should be reusable.

Now that I think about it, instead of replacing the flange studs, I am just going to use stainless bolts.

Yes, I absolutely always use anti-seize on AF sensors.
 
Last edited:
Status
Not open for further replies.
Back
Top