Catalytic converter to exhaust manifold seal

[wkelley70]

I am attempting to install a PaceSetter 324236 catalytic converter setup on my 2006 LJ (4.0 and automatic transmission).

I cannot get either of the flanges on the PaceSetter to seal to the exhaust manifold. I tried the service manual torque spec of 23 ft-lbs, then increased this to 30 ft-lbs. The exhaust continues to leak at both flanges.

My next steps are to remove the cats and do a better job of cleaning the manifold mating surfaces. Outside of that, the only other thing I can think of is to try high-temp RTV. I really don't think that is a good solution, though.

Does anyone have any thoughts about or experiences with this?

 

[P man]

I am attempting to install a PaceSetter 324236 catalytic converter setup on my 2006 LJ (4.0 and automatic transmission).

I cannot get either of the flanges on the PaceSetter to seal to the exhaust manifold. I tried the service manual torque spec of 23 ft-lbs, then increased this to 30 ft-lbs. The exhaust continues to leak at both flanges.

My next steps are to remove the cats and do a better job of cleaning the manifold mating surfaces. Outside of that, the only other thing I can think of is to try high-temp RTV. I really don't think that is a good solution, though.

Does anyone have any thoughts about or experiences with this?

RTV is a no go for me

I'm looking at a picture and I can't decide if there should be gaskets there or not. Did it come with gaskets? What do the instructions say to use?

 

[wkelley70]

The PaceSetter did not come with gaskets. The factory setup does not use gaskets either, though. It is sort of a ball and socket metal-to-metal fit.

 

[P man]

The PaceSetter did not come with gaskets. The factory setup does not use gaskets either, though. It is sort of a ball and socket metal-to-metal fit.

Gotcha..those are usually really easy to seal up. Take it back apart and check for cracks in the new parts? Are you positive it's coming from the ball and socket portion? Do you see black "streaks" to indicate a leak?

 

[AMS417]

Make sure you are tightening the bolts equally. Not just paying attention to the torque spec.

 

[wkelley70]

I pulled the cat and it seems that the OEM bolts are almost pulling through the flange. This is with 30 ft-lbs of torque.




I will try this once again with some washers. I thought that I was pretty careful about applying even torque to each bolt, but I will be even more diligent about this the next go-around.

Thanks for all of your comments.

 

[SSTJ]

When I replaced mine, I found that the down-pipe flange wouldn't meet the exhaust manifold if I tightened it last. Took a bit of wiggling and jiggling to get everything lined up just right. So it may just be one of those things where you need to finger-tighten each piece into place first, and then tighten down in a particular order?

I can't remember about washers in that location. I'm sure your FSM would say.

Also, I haven't read this closely, but it looks related.

 

[JP_in_STL]

I just went through replacing the Pre Cats and Y Pipe over the weekend. I used an AFE brand. I had to use some redneck ingenuity to get everything lined up and sealed. I was working on the ground, no overhead lift. I used a ratchet strap over the top of the engine and down around the bottom to support the pipe assembly and get things lined up. I then needed another strap around the 2 Precats to pull them together a bit more. I could get 3 bolts started with that. Then finally needed a bottle jack under Bank2 Pipe to add a little pressure, that got the 4th bolt started. Then I just worked around alternating and snugging the bolts up.

 

[wkelley70]

I ended up returning the Pacesetter and buying a Magnaflow (ouch$). The Magnaflow did not touch the oil pan, like the Pacesetter did, and sealed to the exhaust manifold without issue.

My hat is off to JP_in_STL. The Pacesetter may have sealed up for me if I would have used his ratchet strap trick. I did notice that the distance between the two entrance openings to the Pacesetter cats was different than that of the Magnaflow setup.

Here are some pictures of the two cats:

Magnaflow:




Pacesetter:


Magnaflow top, Pacesetter bottom:

 

[Steel City 06]

I have the magnaflow cats (including the 3rd cat) and they work well for me.

If the OEM bolts are pulling through, you may be able to use generic exhaust bolts with large washers. Ordinary graded bolts will work for a while, but the heat will degrade their strength over time.

 

[MaximusLJR06]

I have the magnaflow cats (including the 3rd cat) and they work well for me.

If the OEM bolts are pulling through, you may be able to use generic exhaust bolts with large washers. Ordinary graded bolts will work for a while, but the heat will degrade their strength over time.

Nothing like reviving a thread from a year ago. Were you able to reuse your original bolts from the exhaust manifold to the precats? I just ordered the magnaflow setup and want to have new hardware on hand if necessary.

 

[Steel City 06]

Nothing like reviving a thread from a year ago. Were you able to reuse your original bolts from the exhaust manifold to the precats? I just ordered the magnaflow setup and want to have new hardware on hand if necessary.

You can, but there is a good chance they might just snap or round off. I recommend having new bolts in hand. New hardware also makes it easier to disassemble in the future.

 

[LONGJP2]

You can, but there is a good chance they might just snap or round off. I recommend having new bolts in hand. New hardware also makes it easier to disassemble in the future.

Do you have a source for those bolts?

 

[Steel City 06]

Do you have a source for those bolts?

Rockauto sells them. Amazon often carries them too, just watch out for counterfeits. Most auto parts stores will have them in store at a bit more of a markup.

https://www.rockauto.com/en/moreinfo.php?pk=1261515&cc=1432231&pt=13936

Soak your existing bolts in PB Blaster or Kroil prior to disassembly, they tend to seize and it's already a hard area to get a wrench in to.

 

[MaximusLJR06]

Rockauto sells them. Amazon often carries them too, just watch out for counterfeits. Most auto parts stores will have them in store at a bit more of a markup.

https://www.rockauto.com/en/moreinfo.php?pk=1261515&cc=1432231&pt=13936

Soak your existing bolts in PB Blaster or Kroil prior to disassembly, they tend to seize and it's already a hard area to get a wrench in to.

These are the bolt for the third cat where it attaches to the tail pipe / muffler.

Do you have a source for those bolts?

I couldnt find any so i ended up order some M10-1.5 bolts in various lengths. According to blaine and some other posts i saw, that is the size for the 4 bolts at the precats.

 

[MaximusLJR06]

So far the only items giving me difficulty are the O2 sensors. Rest of the bolts came out with little to no effort. Definitely found the source of my rattle. Other side is still in place but deteriorated.