Should have knocked on wood..
- Thread starter Tom in MD
- Start date
Not over yet
Still going. No noticable performance issues or codes. I feel pretty certain it's an exhaust issue. Cats. Sometimes when hot the noise can occur at idle. While this was happening, I got under it and hit the passemger-side Cat with a block of wood. It would stop rattling for a few moments then gradually resume it's chatter. I will have some time off next week and planned to deal with it. Will try to get it into TMC.
Still going. No noticable performance issues or codes. I feel pretty certain it's an exhaust issue. Cats. Sometimes when hot the noise can occur at idle. While this was happening, I got under it and hit the passemger-side Cat with a block of wood. It would stop rattling for a few moments then gradually resume it's chatter. I will have some time off next week and planned to deal with it. Will try to get it into TMC.
P
plus_ar
Guest
thanks for the update
thanks for the update Tom. I am real curious and on the verge of taking it into the dealer. I'm thinking mine may be cats as well, since when i stick my head in the engine compartment, you can hear normal noise and valves. It definitely sounds like it is coming from around the exhaust. I haven't tried the block of wood test yet. Hope one us diagnoses it soon.
thanks,
greg
thanks for the update Tom. I am real curious and on the verge of taking it into the dealer. I'm thinking mine may be cats as well, since when i stick my head in the engine compartment, you can hear normal noise and valves. It definitely sounds like it is coming from around the exhaust. I haven't tried the block of wood test yet. Hope one us diagnoses it soon.
thanks,
greg
Everything I've read here points towards exhaust system leak rather than anything expensive like engine problem. That it happens when warm indicates metal expansion. Get under the truck when its cold and tighten every bolt on the system.
BTDT
BTDT
Tom, also take a look at the connection between the Y pipe and the muffler. The bolts could be loose and if you have an exhaust olive in between the pipes it will rattle also.
P
plus_ar
Guest
Me too
I've really had no quality time to spend on this but plan to this weekend and next week. I did try tightening the bolts at the exhaust manifold-down tube junction and they were already rock-solid. I'll take a peek at the Y-pipe too.
I've really had no quality time to spend on this but plan to this weekend and next week. I did try tightening the bolts at the exhaust manifold-down tube junction and they were already rock-solid. I'll take a peek at the Y-pipe too.
Tom, here's an update-I solved the problem! Like you I had crawled under the truck and pounded on the whole exhaust system and everything seemed intact. After reading the posts from Chris and Eric I checked all the bolts and found several loose bolts on the pass side exhaust manifold. No more noise! Thanks guys.
Closure
It's been months since I started this thread and I thought I'd close it out. Final outcome: replaced the Y-pipe and all is well. As the noise evolved, it became more apparent under load. As suggested by several on this thread, and confirmed by Trevor, the catalyst had broken loose in the converter.
Buying the Y-pipe: A few options available for the part itself. Anywhere from $500 - $1400. The $899 part from Rovers North was recommended, as it was less restrictive than the original. Unfortunately, it's been the summer from hell and I've blown $6K on home repairs, so I went to Nathan for the $500 part. Made in Canada. Fit perfectly.
Removal of Y-pipe 96D1, YMMV :-Night before, soak all the nuts and bolts with Liquid Wrench
-Remove ignition wires from the coil pack
-Remove the cooil pack bracket (4 little nuts)
-Disconnect the front O2 sensors (each has it's own multi plug under the coil pack)
-Disconnect the rear O2 sensors
-Remove 4 bolts holding the front swaybar, let swaybar swing down (watch you don't get your teeth knocked out !)
-Loosen 6 bolts at the Y-pipe-Exhaust manifold junction. I removed 4 and left 2 to hold it up there.
-Remove the 2 bolts at the other end of the Y-pipe where it connects to the rest of the exaust. Mine were so rusted that I had to cut them off with a recipricating saw.
-Remove Y-pipe. My gaskets just dropped out.
-With the Y-pipe removed, I transfered over the O2 sensors making use of some anti-sieze compound. These also came out very easy.
-Instal the new Y-pipe.
Comments:
I was most concerned about the breakage of studs at the exhaust manifold, especially since I had tightened them trying to diag the problem. Surprisingly, they came off intact. 2 studs actually backed out with the nuts, but no broken parts.
O2 Sensors: I considered replacing these, but my OBDII s/w said they were still OK and I was seeing no codes to the contrary. If they fail later, the anti-sieze should make it an easy fix.
The hadware at the back end of the original Y-pipe was a freakish thing that had no bolt head but rather an end that fit flush into the Y-pipe flange. I don't know if this harware could have been reused if it wasn't rusted to hell. The new Y-pipe had no such hardware, just the free-floating flange. I replaced mine with common bolts from the auto parts store.
Gaskets: It was a real bitch to hold these in place while trying to move the Y-pipe into position. I ended up using a scrap of duct tape to temporarily hold the gaskets against the exhaust manifold. Once I got the Y-pipe up there, I installed one nut on each side (loosely) and carefully pulled the tape out from in between the parts.
Thanks to all that responded, esp Trevor, for the good advice.
It's been months since I started this thread and I thought I'd close it out. Final outcome: replaced the Y-pipe and all is well. As the noise evolved, it became more apparent under load. As suggested by several on this thread, and confirmed by Trevor, the catalyst had broken loose in the converter.
Buying the Y-pipe: A few options available for the part itself. Anywhere from $500 - $1400. The $899 part from Rovers North was recommended, as it was less restrictive than the original. Unfortunately, it's been the summer from hell and I've blown $6K on home repairs, so I went to Nathan for the $500 part. Made in Canada. Fit perfectly.
Removal of Y-pipe 96D1, YMMV :-Night before, soak all the nuts and bolts with Liquid Wrench
-Remove ignition wires from the coil pack
-Remove the cooil pack bracket (4 little nuts)
-Disconnect the front O2 sensors (each has it's own multi plug under the coil pack)
-Disconnect the rear O2 sensors
-Remove 4 bolts holding the front swaybar, let swaybar swing down (watch you don't get your teeth knocked out !)
-Loosen 6 bolts at the Y-pipe-Exhaust manifold junction. I removed 4 and left 2 to hold it up there.
-Remove the 2 bolts at the other end of the Y-pipe where it connects to the rest of the exaust. Mine were so rusted that I had to cut them off with a recipricating saw.
-Remove Y-pipe. My gaskets just dropped out.
-With the Y-pipe removed, I transfered over the O2 sensors making use of some anti-sieze compound. These also came out very easy.
-Instal the new Y-pipe.
Comments:
I was most concerned about the breakage of studs at the exhaust manifold, especially since I had tightened them trying to diag the problem. Surprisingly, they came off intact. 2 studs actually backed out with the nuts, but no broken parts.
O2 Sensors: I considered replacing these, but my OBDII s/w said they were still OK and I was seeing no codes to the contrary. If they fail later, the anti-sieze should make it an easy fix.
The hadware at the back end of the original Y-pipe was a freakish thing that had no bolt head but rather an end that fit flush into the Y-pipe flange. I don't know if this harware could have been reused if it wasn't rusted to hell. The new Y-pipe had no such hardware, just the free-floating flange. I replaced mine with common bolts from the auto parts store.
Gaskets: It was a real bitch to hold these in place while trying to move the Y-pipe into position. I ended up using a scrap of duct tape to temporarily hold the gaskets against the exhaust manifold. Once I got the Y-pipe up there, I installed one nut on each side (loosely) and carefully pulled the tape out from in between the parts.
Thanks to all that responded, esp Trevor, for the good advice.
D
dungbeetles
Guest
anthony said:
Sounded like a valve but changed the wires and plugs first just in case. Then I found this post. Those damn 6 bolts!! Only two on the passenger side were loose but it was enough to get me to start pulling my hair. Thanks anthony!!!
Hi guys. I know it's been a couple of years since this thread was posted, but I ran into the same problem with my 99 Disco II last week. When I pressed the gas it would sound like some change in a can, but when I would take my foot off the gas, it would quiet down. Naturally, I'm anticipating the worst, but turns out it was some loose bolts that needed to be tightened. The mechanic said they were about to fall out of their housing. Anyway, he tightened them and my Disco sounds almost as good as it did when I bought it. The icing on the cake was he didn't charge me one red cent!!!:applause:
Well I have been trying to figure out the dieseling sound under load or over 2200 RPM for months and just B4 I took it in to my local LR shop I looked here one more time and .... the six bolts off the exhaust manifolds were only hand tight! Torqued them back down and the beast purrs like the old lion once more. My wife is so happy and my wallet is so happy.
Many thanks to dungbeetles for posting this link.
Many thanks to dungbeetles for posting this link.