So I have a 2005 G35 with the infamous OC issue that occurred at 70k miles.. Every 1k mile I burn about 1Q of 5W-30 oil.. I read that the Gs are supposed to be running conventional oil (specified in the manual) so I was going to switch to that and a higher viscosity to test the OC burn rate.. Right now im testing the OC with synthetic.

I heard these were viable options to combat the issue:
- Catch can
- Higher viscosity oil
- Replacement of oil rings
- Replace engine for the same problem to occur later down the road

Other than that, I have thought about giving up and selling my precious car.. For the owners that have high OC engines, what have you been doing? Have you been adding oil as you go? and how many miles are you at? Please share, as I am curious to know.. I want my engine to last as long as possible since I bought it 3k miles ago LOL

 

SLICK, my coupe doesn't have the OC issue but everything you listed might slow down your issues with the exception of using a catch can! OC is caused by oil ring failure! In the past I've referred to them as, "Cheap Chinese Oil Rings" which may or may not be the case. If you keep your G and replace the motor it's a good idea to get a catch can to keep oil residue out of your plenum, that's it's only job!
Gary

 

This whole OC issue is concerning to me.. especially because I only had the car for 3 months.. It was up until I did my own oil change that I noticed on 2 quarts of oil being returned from the previous oil change which scared the living poo out of me. Id like to give a catch can a try after testing... Id like more solid proof that it may solve the OC issue though. I have already replaced the PVC valve and the G was doing fine for a couple of weeks, but the G started to go to town on the oil again for some odd reason.

 

bwongwong, if you have any indication of OC you need to check your oil level every few days using the dip stick supplied! Top off when needed, it's important to keep it up to the full line! Catch cans only function is to keep oil residue out of your upper plenum, they do nothing else!
Gary

 

If the engine has excessive blowby coming out of the PCV valve at idle it is definitely the rings like Gary said. If you nip it in the butt with a catch can early on like he did then the issue can be avoided completely.

I for one believe that valve cover and timing cover access panel leaks are things to keep an eye out for, too.

If I were you OP, I would install a vented catch can and check for oil leaks at the locations I pointed out above. If it is your rings, then going to a vented can (versus one that hooks into the intake for vacuum) will help reduce oil loss through the PCV system.