I have a s5 n/a and while cruising at a low rpm or idling I have what sounds like rod knock its real light but noticable. Any ideas on what it could be?

 

Rear end, worn suspension bushings, loose accessory banging about. Basically a chassis issue not an engine problem

 

Bad ball joints

 

Ball joints while idling?

 

It's probably a bad rotor bearing...Rebuild the motor time if that's the case. PM if you need a motor.

 

Start with the simple stuff. Park the car on a flat surface, lightly set the brake and rock it around. Grab each wheel and give it a shake, both on the tarmac and up on the jackstands. Grab the shocks and see if they rattle. Check the engine bay for loose widgets. Get the rear end up and spin the wheels by hand and listen for differential/driveshaft noise.

It could be an internal motor probelm, in which case PM Mr rx-7 tt, but check the chassis first.

 

OK thanks. I will go check everything when I do some more work on it sat. Its erratic and dosent do it all the time so maybe it isnt internal probs....... damn I hope not.

 

You may also want to try disconnecting some of the accessories to see if the noise comes from the A/C, P/S, or the air pump. Make SURE you leave at least one belt on the water pump to keep it spinning!

Brian

 

i had that same type of sound, it ended up being my header gasket had a hole blown in it and exhaust was hittin the firewall.

 

OK thanks for all the info I will try to track it down sat.

 

you will love this. Drivers side motor mount missing the bottom nut. I guess that will do it. Thanks for all the help.

 

Haha. At least it was something simple. Would've been less funny if you had torn into the engine and then found the missing nut.

 

Damn I had a feeling that could be a possibility, shouldn't have kept my mouth shut (err, shouldn't have kept my hands off the keyboard I mean)