98 limited rattling noise

[Black798]

Hi everyone, I have been lurking on here for a round a month or so and am pretty new to the 4 runner family. I recently bought a 98 limited 4wd v6 auto. Every since i bought it, the car has had a weird rattling that is most noticeable when the car is on a cold start and you put load on the motor. Ive already ruled out the evap valve being the source of the noise. It seems like it is coming from the catalytic converter but I cant tell for sure. Before I go throwing money at the thing i would like to get some more opinions. Let me know what you think.

 

[Hesk11dog]

noises can be hard to pin down unless a general location is given. When you cat, i would check your exhaust mounts and make sure there is no metal on metal that could cause the rattle. There is a heat shield above the cat, check that as well. What happens when you go over bumps? Rattle means something is loose or broke. Any more specifics?

 

[JayRolla]

Hi everyone, I have been lurking on here for a round a month or so and am pretty new to the 4 runner family. I recently bought a 98 limited 4wd v6 auto. Every since i bought it, the car has had a weird rattling that is most noticeable when the car is on a cold start and you put load on the motor. Ive already ruled out the evap valve being the source of the noise. It seems like it is coming from the catalytic converter but I cant tell for sure. Before I go throwing money at the thing i would like to get some more opinions. Let me know what you think.

At the back of the exhaust manifolds there are heat shields. This will corrode and cause a very bad raddling sound. Just start her up, rev it up from under hood and find where its coming from.

 

[Black798]

Alright so I checked all the exhaust brackets and shrouds and they all are solid as a rock. To me it almost seems like its a really bad exhaust leak. But I pressurized the entire exhaust system to 40psi with my air compressor but I couldn't find anything. I also did a temperature check on the converter and on the outlet side it is about 150 degrees lower than the inlet.

 

[JRZEE2000TR4LTD]

Your substrate inside the catalytic converter could be broken loose. Does it do it when you come to a stop with truck in drive but with brake on? If so then I would say it's broken substrate and the only fix for that is to replace the converter.

 

[Black798]

Your substrate inside the catalytic converter could be broken loose. Does it do it when you come to a stop with truck in drive but with brake on? If so then I would say it's broken substrate and the only fix for that is to replace the converter.

It doesn't do it very noticeably when Im stopped or going over bumps. Its most noticeable when the motor is under load. Like taking off from a stoplight

 

[JRZEE2000TR4LTD]

It doesn't do it very noticeably when Im stopped or going over bumps. Its most noticeable when the motor is under load. Like taking off from a stoplight

If I heard it I would know if it were the substrate. I've had 2 vehicles do this. It's a very distinct metallic, hollow sound. It goes away after a few seconds, right?

 

[WallyWest]

Mine does the same thing. I believe it's the heat shields on the cat. I'm going to confirm or disprove that in the next few days so I'll let you know how it goes. Otherwise I think the substrate breaking loose inside the cat is the next likely candidate.

Mine does it at very specific rpms, and only under load. Doesn't do it at all when in park or neutral just revving the engine.

 

[Black798]

If I heard it I would know if it were the substrate. I've had 2 vehicles do this. It's a very distinct metallic, hollow sound. It goes away after a few seconds, right?

In my initial post there is a video of the noise from bot in the engine bay and under the car. The first round is in park, second is in reverse with the break on.

Mine does the same thing. I believe it's the heat shields on the cat. I'm going to confirm or disprove that in the next few days so I'll let you know how it goes. Otherwise I think the substrate breaking loose inside the cat is the next likely candidate.

Mine does it at very specific rpms, and only under load. Doesn't do it at all when in park or neutral just revving the engine.

That's how mine is and the cat shroud is solid. Its most noticeable at lower rpm, say first to second gear below 2500