Hi. My driver side cat has developed an occasional rattle when the engine is idling warm. Been researching the best option for a y-pipe replacement part and wanted to get advice here based on your experience. Mainly I want a high quality replacement that will be relatively simple for me to install and that will fit well. Looking at the options on AB and RN I am unsure what will fit right other than the Genuine part that is mega expensive. I live in WA state so no CA emissions worries here.

Thanks for the help.

 

I ordered one from eBay, and it absolutely did NOT fit. Was able to get my money back, eventually (had to do a PayPal dispute). Ended up having a local shop cut out the bad cat and weld in a new one, did a very tidy job of it, but it was not that cheap, about $400.

 

Yeah someone cut mine out and need to replace it for CT emissions. I've seen them anywhere from around $280 at Rock Auto to $550 from the LR online stores. Are they're any differences? None are stainless. The only thing I can think of is as above, the fit is not good and/or the tubing walls are thinner, therefore will not last as long.

thoughts?

 

I'm going to reply here with the caveat that i did this a year ago, but maybe it will help you.

In theory, this is a pretty straight forward job. In practice, it was a nightmare.

First, prices; I went the ebay route as well, bought the cheapest one I could find. I believe it was ~ $450. I also previously welded in replacement cats on an original y pipe. Those universal cats were ~$85 each.

Here is a quick review of both.

The real issue replacing the y pipe is a dimensional one. The engineering choices of connection types and exhaust system design in general place manufacturing tolerance requirements on the y pipe that make it not well suited to the aftermarket exhaust industry.

The exhaust manifolds are cast iron, there is a flat flange mating connection parallel to the ground for the y pipe, with a single ~0.125" gasket to seal it.

Add in slop in the manifold holes x2 for both sides and we are already in trouble. And the heads are aluminum, crank on those steel manifold bolts with torque on the manifold due to improper fit and you booger up the holes on the head. Now take into account the extremely close quarters of the y pipe down runs. Finally, the mounting points and pig noses holding the resonator leave you very little maneuvering at the other end. There is an "olive" a spherical ring that fits into that connection, but it only allows for a degree or two of angular adjustment.

And in my state, NJ, exhaust leaks are verboten. So it's gotta seal.

Ok, so given that, here is my experience.

The weld in cats were a pain in the ***. They are very difficult to fit in, especially the passenger side one. There is a reason the cats are different shapes on the original.

Also, I greatly underestimated the amount the welds would pull the flanges; I tacked the cats in with everything bolted up then removed it from the truck to complete the welds. Maybe if you have some kind of welding superpowers and tiny hands you might be able to do it on the truck, but i doubt it. Ended up having to put an oversized union at the bottom of the passenger cat to make up the angular misalignment. Ugly stuff.

And it is thin wall welding on old corroded heat stressed steel. So three months later the welded joints starts to leak, and eventually there just isn't enough clean material to weld back up.

In any case, Given the amount of time I wasted, if the $400 to have someone else do it includes the price of the cats it sounds like a bargain to me.

When that finally gave out I bought the aforementioned ebay jammie. The takeaways from that; the pipe was made out of tinfoil, the flanges were warped in two planes and the overall build quality was atrocious. On first fit-up it wasn't even close. Luckily the crappy materials were thin enough so I could horse it around with the come-along and with a little luck I didn't crimp the tubing in the process. I ended up using a stack of four gaskets on the drivers side and three on the passenger side but got it to seal and pass inspection.

In two years, the ol' girl will be old enough to no longer require inspection at all, so this solution made sense for me. I'll slap in two straight pipes and be done with the whole mess.

If you have any questions I'd be happy to answer to the best of my abilities.

Good luck with it

 

I put a y pipe on my 96 disco last month that I bought from AB. It was pretty straight forward and fit well, took about 8 hours. Good luck

 

Thanks for the suggestions thus far. I think it's fair to say the sourcing a pipe off eBay is NOT the way to go!

Good to hear the one from AB was pretty straightforward. I am inclined to go that route and have had good luck with AB and RN in the past so unless I hear a horror story about either's offering, I will order up and get the job done.

Also thinking about replacing the cat-back system while I am under there.

Please keep any recommendations coming if you think it will be helpful.

Always appreciate the help here.

- Chris

 

Quick note. One thing I also did was run my scanner on the downstream O2 sensors. What I saw at operating temp (when the rattle starts) was one of the sensors fairly steady at about 1v while the other dropped down to about .2v to .4v and varied in between. I am assuming (since I haven't located a proper test procedure) that this means the cat is bad. Oddly, no codes have been thrown.

 

my 2 cents.. I had a local shop replace both on D1 number 1 and has been money well spent (about 3 years ago around $900), D1 number 2 needed the same treatment and I was considering the AB route but was talked out of it by the shop. Citing potential issues with sensors on aftermarket parts and knowing that what they had was ok. After the head aces mentioned on other post, they claimed to have lost money on me at $1400.00 OUCH! so I am sure there are weld-ins that go well and some don't.

I would go with the AB's - new neat and clean.

 

Good point on the sensors and after market parts. I plan to replace the downstream sensors as well (upstream replaced about a year ago).

 

Ordered a complete MagnaFlow system (y-pipe/cats, and cat back with deleted resonator). Truck is 20 years old and the resonator is also a rusted mess so while I am under there I am doing the entire system.

Will report back on any issues/success/failure/etc.