I bought a 2003 G35 Sedan with the 6 speed manual transmission with 173K miles. I drove 2 hours away to get it since it was manual and 4 doors, since I have children, which was exactly what I was wanting. Driving it most of the way home was uneventful as I was driving casually, but when I got within a mile from my house and on a back round I opened her up a bit and after a couple of mild pulls kept it under 6000 RPM. I noticed a slight oil smell so I rolled the windows down and listened to the engine. At Idle it sounds great but between 1000 and 4000 rpm you can hear knocking from what sounds like up top around cylinder 1 area. I thought maybe lifters so I removed valve covers and checked the clearance of the lifters and they are within the specs (0.010-0.013 intake) and (0.011-0.015 exhaust). So I removed the timing cover (power steering bracket is a real PITA) and everything visually looks fine. I have a couple questions though on the VVT sprockets the tensioner on the cylinder 2 side you can push down on the chain and the plunger goes in out freely squirting oil on the chain, but on the cylinder 1 side the plunger is very hard to depress and you cannot see oil squirting on the chain. Is it supposed to be hard or easy to depress the plunger? The other question is on the main tensioner there is a very shiny part of the plunger that looks like it adjusted 4 notches within a short amount of time or all at once. How many notches is considered out of spec or worn?Chain is still tight and the guides don't look damaged. Cant really tell if the previous owner changed the timing chain or not. Could the timing components be my issue of knocking on cold startup for about 1 second and then idle fine but then knock between 1000 to about 4000 rpm. knocking seems to go away or just cant hear due to the higher revs above 4000 rpm. A rod bearing will knock at idle and all rpm ranges correct? Also there wasn't any chunks of metal in the oil or bottom of the pan like a bad rod bearing, although the residue on the bottom of the pan had very very tiny specs which looks almost like a metallic gold paint, but i figure that is reasonable amount of deposits from 173k miles. Oh and one more thing the VVT solenoid also on cylinder 1 side was hard to move the valve in and out, but on the cylinder 2 side was much easier. Thank you in advance for any replies.

 

Any time you see "glitter" in the oil the motor is basically shot. Something is eating itself up. You won't find "chunks" of metal unless something violently kaboomed.

Sorry but that engine is likely toast, what you're hearing is probably rod knock because a bearing is shot.

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If the engine detects the cams are not being properly actuated it will throw a DTC, it knows the exact position of the cams based on data being sent from the phase sensor so it's not likely the problem. If it feels really bound up it wouldn't hurt to replace with a new one but given the obvious glitter in the pan I wouldn't sink a dime more into that motor, instead just shop around for a low mile replacement for under $1k

 

Also, since those cam actuators work off oil pressure and you have obvious contaminated oil they're probably already damaged and will quickly fail anyways.

 

Do you think the car had this issue or did it happened becuase the engine was revved too high?

 

This actually sounds like a bad timing tensioner, it's oil pressure regulated and when they get worn they cause really harsh sounding starts like you are describing. Could also be trashed from glittery oil though since it too is driven entirely off oil pressure.

 

Thanks for the inpit, there is a pull it yourself salvage yard that has a handful of g35s im gonna drop the pans on them and see which engine is the cleanest and might just swap engines.