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How hard is it to replace the exaust manifold?

how hard, depends on your skill level.

nothing tricky about it, there is just alot that must come off because the intake manifold and exhaust manifold are so close together. get a good gasket for the exhaust manifold. some replacement exhaust manifolds come with cheap gaskets.

i will most likely take atleast 4 hours if your not famialr with the 4.o

good luck
 
wishbone said:
make sure your injectors go back from where they came!!!!! Talk about a PITA
Click to expand...

no need to remove the injectors from the intake manifold.

prep work can make or break this project. when i swapped out my cracked manifold for an APN one i spent a lot of time on prep work. i knew that the intake had to come out so i got to looking at all the electrical and vac lines that needed to be disconnected. i labled each side of each connection with like #s. ie 1 and 1, 2 and 2 etc. be sure to lable the pigtail or vac line as well as where it connects at.

after that its a matter of just getting it done. all in all its just turning a wrench, but some of the areas are difficult to get to. the power steering pump + bracket and intake manifold need to come off to get to the exhaust. nothing difficult, just time consuming.

you may find it to be easier to also remove some other parts to give yourself more room and easier access- like the air box.

also, if your manifold is cracked, most likely your motor mount is trashed too. only 1/3rd of the rubber remained in my stock drivers side mm. if the m/m's need replacing and you dont, then your new headder will likely crack due to the engine moving.
 
stewie said:
no need to remove the injectors from the intake manifold.

prep work can make or break this project. when i swapped out my cracked manifold for an APN one i spent a lot of time on prep work. i knew that the intake had to come out so i got to looking at all the electrical and vac lines that needed to be disconnected. i labled each side of each connection with like #s. ie 1 and 1, 2 and 2 etc. be sure to lable the pigtail or vac line as well as where it connects at.

after that its a matter of just getting it done. all in all its just turning a wrench, but some of the areas are difficult to get to. the power steering pump + bracket and intake manifold need to come off to get to the exhaust. nothing difficult, just time consuming.

you may find it to be easier to also remove some other parts to give yourself more room and easier access- like the air box.

also, if your manifold is cracked, most likely your motor mount is trashed too. only 1/3rd of the rubber remained in my stock drivers side mm. if the m/m's need replacing and you dont, then your new headder will likely crack due to the engine moving.
Click to expand...

im about to be doing this to. but you said you dont need to take the injectors off? the haynes had you pulling EVERYTHING off and it sounds like a lot of work. not hard work but a lot of it.
 
well, when I did My TJ, it wasn't the injectors that had to come out, but they did have to be disconnected from their wires, which cannot be mixed up when re-connecting.
Good write up and pics at DailydrivenTJ, and I only assume that the process is about the same, as the engines,exhaust are the same
 
Label the injector connectors when you disconnect the wiring. The injectors do not have to be removed from the intake manifold but the fuel rail has to be disconnected which isn't hard. However do get some new connectors for the fuel rail as they typically break when disconnecting. The rest is pretty straight forward.
 
I have it down to a 2-3 hours job. there is no need to remove the injectors or the connectors, remove all the vac lines (be careful some are fragile), disconnect the electrical from the TB. There is enough slack in the wiring that you can move the intake around to get the exhaust out.
The hardest part of changing the exhaust manifold is the rear lower bolt, need a double jointed wrist
 
I too did this a few weeks back exactly like stewie with the APN header. I too replaced the driver side engine mount while I was in there which was in bad shape. Doing so will probably help in preventing future exh manifold cracks.

You don't have the remove the injectors or rail. Just move the intake out of the way as an assembly, but be cautious of over straining the composite fuel line.

There was one bolt at the bottom that was a bit difficult to reach, but count the number of bolts at the bottom of the header and make sure you get enough torque on them all.

It's not too difficult, but tedious.
 
How much do you torque the intake/exhaust manifold bolts to on reassembly?

Thanks,

Doug
 
Don't forget to check your trans mount too.
 
fubar XJ said:
How much do you torque the intake/exhaust manifold bolts to on reassembly?

Thanks,

Doug
Click to expand...

Hallo. Haynes tells us : Intake and exhaust manifold retaining bolts and nuts.
No:1 exhaust manifold nut 30 Ft-lbs. All other bolts/nuts 23 Ft-lbs.

p.s. No:1 is above in the middle, but there is also a tightening sequence! from the middle to the outs.
 
wim hoppenbrouwers said:
Hallo. Haynes tells us : Intake and exhaust manifold retaining bolts and nuts.
No:1 exhaust manifold nut 30 Ft-lbs. All other bolts/nuts 23 Ft-lbs.

p.s. No:1 is above in the middle, but there is also a tightening sequence! from the middle to the outs.
Click to expand...

Perfect! Thank you.
 
Wouldn't be a bad idea to add in a section of flexpipe somewhere after the downpipe. Like somewhere between the downpipe and crossmember. Should reduce alot of stress on the manifold.
 
The new manifold I ordered off of e-bay has flex pipe built into the down tubes.


Oh, another thing, the fuel rail must be disconnected, yes? I haven't given it a good look over yet, just getting my facts straight while waiting for the new manifold.
 
You're right, for some reason I was assuming there was similar flex joints on the other tubes. At any rate, it was cheap, is a new part, and has a one year guarantee. Beats the Hell out of some of the other manifold prices I've seen. Maybe I'll get snakebit and the thing will crack out in 13 months, I'll find out.
 
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