I'm just wondering what kind of problems I could run into while removing the exhaust manifold. This would be the first time removing a manifold from a engine having an aluminum block. Will the bolts likely be seized? Will the threads from the aluminum block come out with the bolts? Ya know fun stuff like that...

The reason I'm removing the manifolds is because of a frame rusting issue next to the catalytic converter (right side). I need to drop the y-pipe. then weld in some patches. I started the procedure by disconnecting the O2 sensors. Then started removing the nuts that connect the y-pipe to the manifold. These studs started breaking so I stopped. Should I continue and break the rest of the manifold studs and remove the manifolds.

thanks

From a guy who hates exhaust work!!!

 

Use PB Blaster on every bolt. Let it sit for about 20 minutes and spray again. Then let sit about an hour before unbolting. You can order the bolts for both the downpipe and where the manifold bolts to the block. Just be patient and make sure you let the PB Blaster do its work.

 

SB, guys with DII's don't know from the lock washers that plagued anyone removing manifold bolts from DI's or RRC's. DII owners are lucky, they have nice 12 point 12mm bolts with big spacers making it as easy as pie to remove them from the heads.

 

No issues removing either header, i was a bit surprised how willingly they came out.

 

Good to hear DIIs aren't problematic in this area. I'll spray them and let them sit just a precaution. I got to get this LR on the road, so I can off-road.

thanks guys!!!

 

I have the same rust issues on the frame as you. Adjacent to the passenger side catytic converter. I don't believe you need to remove the manifolds to patch the rust. Just remove the three bolts holding the YPipe on. Removing just the YPipe should provide plenty of working space. That's all I plan on doing.

 

I also planned on removing just the Y-Pipe. What I didn't plan on was all 6 manifold studs breaking.... So heads up.

I figure now the best way to get the studs out is to remove the manifolds first. This Thread was to got some feedback about more problems that might arise from removing the manifolds. It sounds pretty straight forward though. I'll let everyone know how it went. I haven't worked on it since last Saturday.

Oh yeah... Anyone know the thread size and pitch for the manifold studs? I'm going to get a tap to clean up the threads after I remove the little bastard studs.

 

I found it always best to use an impact wrench for removing the nuts from the studs on manifolds. That way you lessen the build up of torque on those studs.

If you don't have an acetylene torch to heat around the remains of the studs you may find it nearly impossible to remove them.

Should you find yourself in a bind with freeing up the studs keep in mind I sell a pair of manifolds, glass beaded, ready for high temp paint with clean studs and chased threads for just $89.99 a pair plus shipping.

Land Range Rover Pair of Exhaust Manifolds 3 9L 4 0L 4 2L 1990 2004 | eBay

I'm not trying to capitalize on your misfortune but you could be facing a lot of work removing six broken studs from those manifolds. I've removed hundreds of broken studs and, like I said above, unless you have an acetylene torch and are good installing helicoils, you could be setting yourself up for hours of frustration.
Cheers,
Paul

 

I broke off all of mine as well, I ended up drilling out the manifold and Y pipe with a 5/16th bit (I believe, it's just slightly bigger than the existing threads) and using a bolt with a nut with a lock washer (a bit of a pain to tighten by yourself) and for the 3rd hole I cleaned up with a tap and used some grade 5 bolt that I measured the length rather than using a stud.

Works great, no leaks.

 

And I actually didnt get around to cleaning the 3rd bolt hole for awhile, just ran 2 bolts each and if you torque them down nice and snug you wont have leaks.