I recently bought a 2003 Infiniti G35. It has 210,000 KM's so its certainly not new.

After about 3 weeks of driving, it developed an engine knock, but in a rather strange way-

When the car is cold it sounds just fine but after it warms up the knocking noise is very audible. The car pulls just fine and the noise is not too bad when driving as it goes faster with the RPMs, but it is still there.

I took it to my mechanic, he says he thinks it is a connecting rod hitting the crankshaft but he cant be sure without opening the engine block. He does not work for the dealership. I know I read some issues about valve caps causing knocking in G35s, and it sounds like its coming from the top end but it could just be reverberation.

Here is the engine when cold

http://videobam.com/EQJtr

And this is it after it's warmed up

http://videobam.com/goFcH

Any ideas?


Thanks!!

 

Unless the connecting rod is broken or missing the cap I doubt it is hitting the crank... Why a mechanic would tell you that I don't know... How did he make that diagnosis? Did he take a stethoscope and listen to the bottom end? You said it sounds like the noise is coming from up top.. Did he confirm the same nose? Is your MIL on? if so did you get any codes pulled? Maybe those could point you in the right direction also... Good luck... Keep us posted..

 

Yea he went over with a stethoscope he said. He thinks the rod is broken. Would the rod being broken affect driving? Because so far I have not noticed a difference in performance. No codes pulled as far as I know. I've been reading about lifter issues causing a knocking noise, but that seems to be from the passenger side and this is directly from engine block.

 

Broken rod won't cause an MIL, it'll just fail on you one day and you'll know when that happens. Then it's time for a new engine good luck

 

Hmm, I'm thinking my only option is to take the car to the Infiniti dealership and have them diagnose it. I really don't want to spend 500 bucks and have them tell me the same thing though, especially with an engine with so many KM's on it.

Any good sites for buying used engines off of? I'm up in Canada, but if need be I can order to a relatives address in the states