Thought maybe you could help on my 1997 d21 Nissan Hardbody

[brc19761]

Everyone on here has gave me such great advice on my pathfinder. I thought maybe you could help me out on my truck.

 

I have a 1997 Nissan Hardbody (d21) reg cab 4 cylinder manual 4x4 that is in excellent shape. It has 136,000 miles on it. I bought new and have treated it beyond great.

This is the problem: I drove to my girlfriends house which is around 80 miles one way. The truck drove fine on the way up there. On the way home as soon as I started up the hwy. I heard this awful rattling noise. The more my speed increased the louder the noise got. It sounded like it was right underneath the driver's seat or under the instrument panel. I made it home. I checked for anything loose couldn't find it. I thought it may be the speedometer cable so I unhooked it from the transmission. That wasn't it. It was definitely NOT coming from the engine

Then I kind of briefly heard the noise while I had it parked and the engine on. It sounded like it was the catalytic converter making the noise. I pushed down on it with a piece of metal and it seemed to stop.
So, I had some metal banding material and pulled the converter down and put the flat metal material on top of the converter and used tappers and an impact to secure it down. This did help the loudness of the noise, but it did not stop it. I have spent at least five times strapping the catalytic converter in various positions. It helps but it does not solve the problem.
Just like today I need to use my truck, but I am afraid that something else may be wrong with it like the transmission (which shifts fine). I even thought it was the throw out bearing, but it does not make any noise when running and setting still. It only does it when you drive it especially does it when the motor is going up a hill. It does it really bad when you hit 55 mph and then let off the gas.
The truck runs and shifts great except for this rattling noise that has started. I just don't want to keep driving it and eventually tear something major up.

Anyone have any ideas b/c I sure need them.

[Slartibartfast]

Sounds like a busted exhaust hanger to me.

[brc19761]

Actually all the exhaust hangers are firmly in place. I will tell you one thing. Years ago my check engine light came on. I hooked my ob2 scanner up to it and it was the oxygen sensor in the exhaust manifold. I tried getting the O2 sensor out. I bought a special socket. I let it soak in penetrating oil. I let some friends with some big muscles pull on it, but it was seized and would not come out. I eventually just cut the wires to the O2 sensor b/c I was going to crack my exhaust trying to get it out. I do not know if the catalytic converter could be stopped up. I get the same gas millage. I don't even know what the symptoms of a stopped up converter are b/c I have never had one stop up on me.

[V8path]

When you change the "tension" on the cat, this affects the amount of movement, but you say the noise is still there but bit quieter. Sounds like it might be something inside the cat which is why the noise lessens when changing the mounting tension, so whatever is inside is still rattling around.

[Kingman]

If it's rattling and nothing is loose, more than likely it came apart inside and you have a great excuse to put a Magnaflow high-flow one on.

[Terranovation]

Sounds like the cat might have had it's day. I used to be an exhaust fitter and we would oxy cut them open to see what damage was inside. Inside a cat is a honeycomb material like in a bee hive and carbon from exhaust fumes can plug up the holes with build up but it takes at least 100,000 kms before it would need changing, unless the fuel going into the tank had a lot of crud in it which ends up going through the exhaust, blocking the exhaust flow and creating poor performance.

[brc19761]

Thanks for the replies. One of my early theories was that the stuff in the cat. converter had came apart. I had to use my truck yesterday b/c I had to haul stuff. Not to long ago I put a new tie rod end on the passenger side. It is my own fault, but I never got the front end aligned. I usually don't take my truck on long trips. I use my Pathfinder for that. I have had to use my truck on long trips here lately. I think the tires have worn unevenly b/c of me not getting the front end aligned.

 

I think maybe this has been causing my truck to shimmy which could cause the exhaust especially the cat. converter to shake (and probably broke up the carbon inside of it). When you are at around 60 mph and let off the gas it rattles the most almost like clock work. I bet this is b/c of my tires. I have 31x10.50 all around. I will see what a front end alignment and tire rotation will do.

 

Does anyone think this is a viable theory?

[V8path]

No matter what other issues you have, the cat should not be rattling like you describe. Fix that, and if the alignment is causing vibration, that's another (SAFETY) issue that should be fixed regardless of the cat.

[Slartibartfast]

I would be surprised if it broke the cat due to an alignment issue, but yeah, shimmy isn't a good thing. Get that sorted out, then track down the rattle if that's still there.

[brc19761]

Thanks for the info. Yes I will have to get both issues fixed. I am always thankful for this sites great advice. Everyone has always helped me out tremendously and save me a lot of $,

 

Thanks,

 

brc

[adamzan]

Everyone on here has gave me such great advice on my pathfinder. I thought maybe you could help me out on my truck.

 

I have a 1997 Nissan Hardbody (d21) reg cab 4 cylinder manual 4x4 that is in excellent shape. It has 136,000 miles on it. I bought new and have treated it beyond great.

 

Actually all the exhaust hangers are firmly in place. I will tell you one thing. Years ago my check engine light came on. I hooked my ob2 scanner up to it and it was the oxygen sensor in the exhaust manifold. I tried getting the O2 sensor out. I bought a special socket. I let it soak in penetrating oil. I let some friends with some big muscles pull on it, but it was seized and would not come out. I eventually just cut the wires to the O2 sensor b/c I was going to crack my exhaust trying to get it out. I do not know if the catalytic converter could be stopped up. I get the same gas millage. I don't even know what the symptoms of a stopped up converter are b/c I have never had one stop up on me.

Something does not add up here...

 

Even here in rusty ass canada I had no issues taking the o2 out. Use a small propane or mapp gas torch to heat it up...

 

As for the rattling, unbolt the cat and see what it looks like inside, that will give you the definite answer.

Edited August 9, 2015 by adamzan

[Slartibartfast]

I had a lot of trouble getting the O2 out of my '95 (ended up breaking it in two pieces actually). No corrosion issues on it either, I just didn't think to heat it.