3.9L common exhaust problem - Land Rovers Only

Drewfuss · 03-16-2006, 01:42 PM

Errr!! This summer I disconnected the entire exhaust (since I was afraid to tackle the rusty bolts at the flange to the muffler) and found the source of that annoying exhaust leak. Apparently, the flange on the Y pipe (NAS driver's side) has a known history of cracking right at the base of the pipe to the flange, causing the wonderful puttering sound upon acceleration (and decreasing gas milage by about 3-4 miles per gallon). I was able to lower the exhaust assembly enough to get a bead of weld on the crack, but just the other day the sound began to re-appear. I admit my welding skills are ugly at best, but they seem to work. With the sound beginning to reappear, I went online to see what the cost of a new Y pipe would be (figuring that you can only band-aid something for so long). To my delight, I found the assembly was only $580 (meaning I would save myself $580 because there's no way I can see spending that much). SO.... anybody have any ideas? Can you buy just the flanges anywhere? Am I stuck with simply goobering-up my existing flanges with weld?

TerryS · 03-16-2006, 02:24 PM

I've not heard of the flange problem before your post. The price you were quoted may be a bit high, and I know there are aftermarket Y pipes available for RR for the various configuration. I believe I was quoted $345 for one for my sons RR. I stopped trying to remember details and dimensions a long while ago, but I remember that one Y pipe, like maybe it was for thr LWB, can be cut back for the Disco and SWB, so maybe one of them would work on your ninety with some bodging. Carquest has a variety of exhaust parts, including many shapes and sizes of flanges. The other option might be to just cut it off, and make a slip joint to the muffler.
We have 3 different V8 landys, and I've worked on lots of others (lots) , and I honestly never saw this problem.

Muddy Oval · 03-16-2006, 06:04 PM

I haven't seen it either and we go through LOTS of D90's in the shop. There's six of the suckers out there right now.
There are cheaper pipes out there, but you get what you pay for. If it's just the flange- cut the sucker. Only reason to replace a Y pipe is if the cats are bad.

Drewfuss · 03-17-2006, 10:04 AM

Thanks for the info guys! I think you're both right; probably the best thing will be to hack the flange off and weld a new one on there. The cats seem to be fine, with the exception of the heat shields starting to fall off. The reason I mentioned the flange crack as a "common problem" was because that's what I was told. I was lucky enough to run into a rover mechanic that used to work at the local dealership, when I mentioned the leak which I thought was coming from the flange not sealing tight, he told me about the cracking that he'd seen many times before, and actually told me EXACTLY where it cracks. Sure enough, when I got in there and looked very closely from the inside, there it was!

robbie · 03-20-2006, 05:31 PM

yep, had that crack and leak on my 95. also had one of the cats go bad so replaced the whole y-pipe.