I have a problem and have not been able to locate any posts of anybody with a similar issue. I have a 95 4runner 3.0 5 speed with 133k miles. The engine has a knocking noise coming from it. It sounds exactly like a rod but is coming from the exhaust pipe. I used a stethoscope to check the pan and then the exhaust. It is definitely from the exhaust. It will vary in volume depending on the engine temperature but it never fully goes away. The noise resonates through the exhaust up to the catalytic converter. I also have a small amount of water coming from the tail pipe. I have removed the heads expecting to find a blown head gasket, possibly between two of the cylinders. Both gaskets were in fairly good shape. Any help or ideas would be greatly appreciated.
Thanks

 

The valves seem to be in decent condition. The knock is constant and increases with rpms. There was no pop from the exhaust aftrer reving it. Could this be coming from a cracked flywheel? The knock does not change with or without the clutch engaged.

 

I can only speak from experience here, and that has been when an exhaust leak is present it will make a LOUD TICKING or even a sound like a light knocking. Sealed up the exhaust system (complete PIA by the way) and no more ticking or clanking.

22RE or 3.0 same thing. It will also cause a rough idle and make it a complete booger to diagnose.

Depends again on the size of the leak, the bigger the louder. The cross over pipe is a definate culprit on the 3.0 and the 22re is almost always the manifold.

Not saying this is your issue, but it sounds like something I might check out.

 

what about the catalytic converter it self? those honeycombs in them can become dislodged and rattle. i have had that happen on mine, i just removed it and put in a piece of exhaust pipe

 

I believe I have this exact problem. My '95 3.0 4runner sounds fine when you start it up after a long rest (cold/cool) and as I get down the road a block or two I start to hear a clatter especially when the revs get a little higher and then fall off to a cruising speed. It won't make the noise if the revs are at 1500-2000, but up around 2100-3000 it's notable and it goes away if I get the revs up really high or I'm under hard acceleration. It's coming from the passenger's side of the engine, and it's really low (not on top).

Last week my mechanic replaced the timing belt tensioner pulley (with the engine water intake running through it), the timing belt, the water pump, and thermostat. The engine quieted down, but it's still making this "knock" or clatter sound.

If anyone has words of wisdom, I'd appreciate it. I hate the sound and want it gone.

joe