Tips/info On Replacing Exhaust Manifold Gasket

[91Pioneer]

OK well I got my harmonic balancer replaced and everything back together. The engine is so much quieter now with the metal-on-metal squealing gone :rock on:

 

Anywho, now I can hear my very slight exhaust leak all the more. It's not a loud leak but it is an annoying one. I definitely hear it while accelerating, less so while I'm cruising at a steady speed. It's not loud like a muffler is gone but noticeable, and makes my truck sound crappy.

 

So I want to replace my exhaust manifold gasket. Specifically:

- do you guys have a specific brand of gasket to recommend?

- any tips or tricks for the installation?

- how hard is it to reach the bolts under the intake manifold?

- should I use any special hardware or loctite when reinstalling things?

- should I replace the intake manifold gasket at the same time? It looks like I should since I'll probably have to take the intake off too (not sure on that though)...

 

Thanks.

[FrankTheDog]

Intake and exhaust use the same gasket.

Clean everything real good.

I use spray tacky gasket to hold it in place on the head while I put the manifolds in place.

I have always used felpro gaskets with no trouble.

When tightening start at the center bolts/studs and work in a circular motion out.

Put a new donut gasket at the collector flange.

Check the manifold over real well for cracks, if you find them weld or have them welded up.

No need for a new manifold.

[91Pioneer]

Typo, I meant intake manifold gasket, not manifold.

 

How do you reach the lower bolts? And do I need to remove the exhaust down pipe to do the job?

[yxmj]

As the dog says above .....the intake and exhaust use the same gasket.

 

The bottom bolts are a bit of a pain but it makes it easy if you remove as much as you can off of the drivers side fender (air box , washer reservoir ect.) Then you should be able to reach in easy with a ratchet and extension to get them.

 

The bolts tighten down in a rotation starting with the bottom third from the back one (the hardest to reach). you should be able to google a pic of the correct tightening sequence or if you have a Haynes or Chilton manual they have it.

 

One trick i read online but never tried......the guy had 3-14mm sockets and 6 " extensions... he finger tightened the 3 hard bolts down and then put the sockets and extensions on them before he put on the intake (left them on) that way he did not have to find the bolt each time only the extension. I never used the tip ....but. :dunno:

 

Oh and I just let the manifold/header hang there.....never seems to hurt it  :thumbsup:    . :MJ 1: .

[1989 Eliminator]

I just did this replacement actully!

 

I take off the powersteering pump and bracket which lets you get to some of the lower bolts better. You can get all but the last two (closteset to the firewall) from the top. The last bottom two you can get from the bottom. With these two, a swivel and 9/16 socket with extension can fit over top of the manifold. This is the best way. The other way is to use a wrench and reaching inbetween the manifold and block. THAT IS A PAIN.

 

Make sure you clean the block surface from old gasket material.

 

I left my exhaust manifold still hooked up so I didnt have to replace the donut gasket. Doing this though... It can be kinda tricky getting the gasket seated between the exhaust manifold and intake manifold getting in your way.

 

Depending on if you ever took your injectors out, you can keep the clips on and carefully pull them out still connected to the fuel rail. Otherwise take the clips off ( AND DO NOT LOSE THEM!! ) Use di-electric grease on the new o-rings when installing the injectors back in. I left my injectors in the fuel rail and placed the fuel rail on top of my valve cover with the wire harnesses still connected too.

 

VERY IMPORTANT!!!!!!

 

DO NOT forget to screw in the egr hose before tightening all the manifold bolts. otherwise it is very hard/impossible to get the tube in the holes. I install the tube just before I'm ready to put the bolts in and screw it in a little to get the threads started.

[Keyav8r]

I put a NOS exhaust manifold on my 88 because the PO had rigged a fabricated downpipe (with a right angle joint) and totally messed up the manifold. I removed the power steering pump and bracket to get access to the manifold bolts at the front. The bottom two at the back were difficult but doable.

Soak every fastener with penetrating oil/WD-40/the other good stuffI can't remember for a couple of days ahead of time. Use the Fel-Pro gasket and put a new donut gasket on the exhaust. Wire brush all the fasteners before you put them back. Woulldn't hurt to run a tap in the holes. Don't forget the EGR tube tip above, it's a b!#€¥ if you wait until everything else is good and tight (ask me how I know that!).

Good time to replace oxygen sensor, too.

Wear mechanics gloves unless you enjoy skinned knuckles and bleeding.

[91Pioneer]

Aw crud. I have one of those snake inspection camera things and I snaked it down and looked along the exhaust manifold, especially where there are welds. And, it appears there is a big long crack around one of the tubes. DOH.

 

So is it pretty easy to get a welder dude to weld it up or should I just buy a replacement manifold? I'm not concerned about cost. I'm thinking I should just buy new and be done with it.

 

And, if I'm buying new, which is the best manifold to buy for the Renix?

[91Pioneer]

I went back and looked over the manifold again, and noticed more cracking, so both collectors from the #5 and #6 cylinder are cracked.

 

I was looking on eBay and it looks like I can go one of:

- Omix-Ada

- Dorman

- Crown; and

- Mopar OEM

 

Now to research each and compare pricing :thumbsup:

[gogmorgo]

Yeah, the long manifold tends to crack pretty badly. If you were to weld it up, it would likely just crack again right next to the weld. If you're doing anything with the rest of the exhaust, it wouldn't hurt to throw in a section of flex pipe to prevent the new manifold from cracking, but it'll likely be fine by without it. I've looked into this, as my exhaust isn't worth much even to a scrap metal recycler any more, and I think I remember at least one aftermarket manifold that had what looked like flex segments within the manifold itself.

[91Pioneer]

My exhaust is relatively new from the joint at the manifold all the way back to the tip at the bumper... I think no matter what I do, I'm going to put a section of flex tube in the exhaust, that ought to decrease the tendency to crack. Unlike Rob Ford I say no to crack! :laughin:

[Keyav8r]

I bought a NOS OEM exhaust manifold for my 88 from Jackson & Son Jeep Parts in Talladega, AL. Installed it with a new downpipe, Fel-Pro manifold gasket and donut gasket. No leaks. Check your motor mounts. If they are worn or broken there will be more stress on the manifold.