Anybody ever changed an exhaust manifold on a '90 4.0 XJ? Any advice before
I make the attempt?

 

CDawg1506 did pass the time by typing:
> Anybody ever changed an exhaust manifold on a '90 4.0 XJ? Any advice before
> I make the attempt?

Not on the XJ, but on the ZJ so some of the following might not apply.

PB blaster on all the studs and especially the two downpipe bolts.

Watch the fuel rail support under the intake plenum.

You don't have to take the fuel injectors out or the rail off.

I found that removing the airbox gave me a lot more room to work.

Follow the torque specs and order. (if you don't have them I'm sure
others here will or I can give you the 4.0 ZJ ones (same spec))

Make sure the side of the block is clean (good scrunge pad/brillo)
make sure there are no carbon tracks.

A bit of formagasket copper on the engine block side will help the
new gasket stay. You want only a thin (suntan lotion thin) coat

Use antisieze on the bolts. and remember you have to go back
at least twice to check. Once after you first warm it up and cool
down then again about a week later. Some of those bolts can't be
gotten to with a torque wrench so learn the feel on a crecent wrench.

Sleepy.. more later. :)

--
DougW

 

CDawg1506 did pass the time by typing:
> Anybody ever changed an exhaust manifold on a '90 4.0 XJ? Any advice before
> I make the attempt?

Not on the XJ, but on the ZJ so some of the following might not apply.

PB blaster on all the studs and especially the two downpipe bolts.

Watch the fuel rail support under the intake plenum.

You don't have to take the fuel injectors out or the rail off.

I found that removing the airbox gave me a lot more room to work.

Follow the torque specs and order. (if you don't have them I'm sure
others here will or I can give you the 4.0 ZJ ones (same spec))

Make sure the side of the block is clean (good scrunge pad/brillo)
make sure there are no carbon tracks.

A bit of formagasket copper on the engine block side will help the
new gasket stay. You want only a thin (suntan lotion thin) coat

Use antisieze on the bolts. and remember you have to go back
at least twice to check. Once after you first warm it up and cool
down then again about a week later. Some of those bolts can't be
gotten to with a torque wrench so learn the feel on a crecent wrench.

Sleepy.. more later. :)

--
DougW

 

CDawg1506 did pass the time by typing:
> Anybody ever changed an exhaust manifold on a '90 4.0 XJ? Any advice before
> I make the attempt?

Not on the XJ, but on the ZJ so some of the following might not apply.

PB blaster on all the studs and especially the two downpipe bolts.

Watch the fuel rail support under the intake plenum.

You don't have to take the fuel injectors out or the rail off.

I found that removing the airbox gave me a lot more room to work.

Follow the torque specs and order. (if you don't have them I'm sure
others here will or I can give you the 4.0 ZJ ones (same spec))

Make sure the side of the block is clean (good scrunge pad/brillo)
make sure there are no carbon tracks.

A bit of formagasket copper on the engine block side will help the
new gasket stay. You want only a thin (suntan lotion thin) coat

Use antisieze on the bolts. and remember you have to go back
at least twice to check. Once after you first warm it up and cool
down then again about a week later. Some of those bolts can't be
gotten to with a torque wrench so learn the feel on a crecent wrench.

Sleepy.. more later. :)

--
DougW