knocking.. but only in idle, or non load

[NashvegasCG]

Hey guys, over the last week, I've been getting a slap or a knock sound coming from the engine bay passenger side. When in the car, it is very audible and is easy to hear when sitting still. When under the hood, it is not as easy to hear. Maybe because of exhaust, maybe because of other noises.. can't tell. When you drive off, the sound either goes away, or gets quieter for sure. It gets louder when you release the gas when slowing down. My first thought was ac belt, or water pump belt, but they are both in good condition. It doesn't sound like a ping, like top end, but it's only on one side it seems. My next thought was a pump of some sort? or maybe a loose timing belt slapping against the protective plastic shield... Any tips or advice would be appreciated.

 

[schmiddr2]

If it is not going at the same speed as the engine then it sounds like something external of the engine is loose. When the motor untorques when you let off the gas - the loose part then has room to move. A motor or tans mount can make more noise in car then out. Hopefully it's not a timing belt bearing.

 

[NashvegasCG]

If it is not going at the same speed as the engine then it sounds like something external of the engine is loose. When the motor untorques when you let off the gas - the loose part then has room to move. A motor or tans mount can make more noise in car then out. Hopefully it's not a timing belt bearing.

Hmm... interesting thought. I didn't think to check the mounts. I dont think it is a mount because it only does it when I release pressure on the motor... it is not a thunk, or a clank... it is an audible deep slap that is timed with the motors rotation from the best I can tell.

 

[H-town_Ryda_06]

Might just need a valve adjustment. Check on YouTube to see if thats the sound ur hearing.

 

[NashvegasCG]

Everything I see on valve adjustment is on the f23 not the j30. I'm still searching

 

[619rcr]

Hey guys, over the last week, I've been getting a slap or a knock sound coming from the engine bay passenger side. When in the car, it is very audible and is easy to hear when sitting still. When under the hood, it is not as easy to hear. Maybe because of exhaust, maybe because of other noises.. can't tell. When you drive off, the sound either goes away, or gets quieter for sure. It gets louder when you release the gas when slowing down. My first thought was ac belt, or water pump belt, but they are both in good condition. It doesn't sound like a ping, like top end, but it's only on one side it seems. My next thought was a pump of some sort? or maybe a loose timing belt slapping against the protective plastic shield... Any tips or advice would be appreciated.

Have you checked your oil level? Also try removing your drive belts and idling the car parked. See if the noise goes away. Try jacking up the front & reving up the motor and check for the noise in neutral & in gear too.

 

[NashvegasCG]

Have you checked your oil level? Also try removing your drive belts and idling the car parked. See if the noise goes away. Try jacking up the front & reving up the motor and check for the noise in neutral & in gear too.

oil is ok, changed it 100 miles ago. no noise in first gear, but yes to neutral and park... will jack up tm and see.

 

[Ghost Ryder]

Hmm... interesting thought. I didn't think to check the mounts. I dont think it is a mount because it only does it when I release pressure on the motor... it is not a thunk, or a clank... it is an audible deep slap that is timed with the motors rotation from the best I can tell.

Hhhmmm. Interesting. Maybe you already have done this, but I would check loom, cables, hoses, etc. for freshly worn spots on them. Maybe around the eng compartment in general. Also, inspect
-exhaust hangers. (One may be cracked or torn, but may not show it when not under stress. I.E. sitting still v.s. driving with vibrations and other movements.)
-Rubber counter weights on the cv axles, if yours has them. I had one that was completely detatched from the axle. But never moved from the same spot. However when accelerating, it vibrated horribly. Only when I touched it and felt althe free play, did I suspect it.

Hope this helps.