Hi everyone! I have a 2003 Z with 73k miles on it! I bought it and drove it for the 14 days that insurance gives you “free” coverage, after purchasing, and I never smelled burning oil, or ever saw smoke from the exhaust. My Z sat for around a month, as I just bought a new transmission, clutch, etc... and was waiting to install it. While the Z was parked I did an oil filter and oil change. I put in 5w30 full synthetic. I’ve put around 500 miles on the Z since then, and it’s started to burn quite a bit of oil. If I rev it up, I’ll see a cloud come out. And if I’m driving it, I can smell the burning oil. I’m not sure what my next steps should be... should I go back and try a blend of Synthetic and Conventional? I’m just not sure where to go...

 

Changing oil to a different blend will make no difference. Too bad you didn't invest in a full mechanical assessment of this Z before you purchased it. Now, the best you can do is take it to a certified tech and have a compression and leakdown tests done to determine what condition the valve seats and rings are in. After evaluating the results, you can decide what steps to take.

 

Alright so your saying that it’s going to burn oil like this the rest of its life? Interesting.. but why would it not burn oil before the oil change, if the blend won’t make a difference?

 

It's impossible to speculate on why you didn't notice the oil burning before. But you changed to a oil with the viscosity specs Nissan recommends for a VQ35DE and it is clearly burning oil. That won't go away and wishful thinking (or a higher viscosity oil) will only mask the symptoms. Did this Z come with full service records? With only 73K on it, it should have had regular oil/filter changes.

 

73k rode hard miles...

 

Unfortunately no service records.. and yeah I am assuming it’s hard miles unfortunately I’ve had to do many many repairs so far..

 

Alright so I have been doing a BUNCH of searching around for answers. I found this post on another website and I would like to hear some feedback from you guys. "What oil are you using, if you are using synthetic then the very FIRST thing I would do is switch back to the factory Nissan oil. I had massive OC issues with synthetic but almost nothing with conventional."

Also I was thinking maybe throw a catch can in. That would catch the passenger side PCV, and then do I just put a little air filter and block off on the driver side? Thanks guys!

 

Speaking as someone who rebuilt their heavy oil consumer engine... there is no quick fix... you will only mask the problem. Seller probably put heavy wt oil in it knowing it was an oil consumer. Maybe you didn't notice because you didn't drive with the windows down, or certain driving conditions will induce more smoke IE: compression braking downhill and then getting into once on flat ground... I used to get a HUGE plume of smoke out of my car doing that. WOT take offs would do it too... Anyhow, all the catch can does is keep oil out of your intake, it won't stop what ever the internal problem is... be it rings or valves. A vacuum gauge test can tell you a lot. As will a compression AND leak down test as suggested above. Sorry... some people are dishonest. I bought my Z used off a dealership lot and found out a week later about 'oil consumption'

 

Thank you Thirzty for the quick response! I really appreciate your knowledge man!!

 

Am I doing more damage to the Z if I continue to drive it? I check the oil every time I start it, and refill if need be.. I dont want to make the engine worst if I can.

 

The easy answer- No.
Keep your oil topped off and enjoy your car.

 

The wear to the engine is already there. But driving it near redline is not a good idea. You should get some testing (compression and leakdown) to get an idea of whether it's rings and bearings or piston rings that need work.

 

100% agreed. I mean dk is the master of all this!
But for the hell of it, I would rebuild the engine. Great way to learn what all is going on (or going wrong)

 

Lets say that we did that and it turns out to be piston rings, valves, etc. I know they are all different things, and we need to determine the source of the problem. Ballpark, what would a shop charge for the work and everything? At the end of the day, I’m just a teenager with a full time job 😂 Money flow is an issue haha!

 

There's no way to ballpark such an estimate. Regional shop rates vary, and depending on the nature of the problem(s), cost can vary widely. Regardless, it's going to be expensive and may exceed the cost of your Z. For the time being, don't push your car hard and keep a sharp eye on the dipstick. You do know the best way to check it, right?

In the meantime, consider doing some research on a used oil analysis (UOA). Getting a UOA sample and sending it off is a cheap and easy way to get a read on the condition of your engine. Using a commercial lab like Blackstone is something a teenager with a full-time job can easily afford.

 

So here is how I check my oil. Before I start the car, I pull the dipstick, clean it, then put it back in and pull it back out. If there’s a good amount in there, I fire her up, let her idle for a few, until my coolant is starting to warm up. Then I shut the car off and check it again. Then fill if necessary.

That sounds like an awesome idea for checking the oil, thank you DK! As far as, if it costs more then the car itself... this is going to be a nightmare.. thank you DK

 

https://my350z.com/forum/engine-driv...il-levels.html

No matter what you find, maybe consider this situation as a challenge, not a nightmarish. These Z33s are getting rare and you are lucky enough to have one--as a teenager no less! These engine problems allow you the opportunity to learn about what makes them tick. Even if you don't have the skills, tools and knowledge, you can gain a start on rebuilding your Z. No, you can't show off, or run that car hard, but she could be the path to an education.

 

Exactly! My Z is the only reason I know anything about cars (or well this platform anyways). Reading through this forum, watching YouTube videos, asking questions. This is how I learned to take off my front end, replace parts, and replace my timing chain, check compression, learn causes of codes, and much more!
dk is right about this being an opportunity to learn. Plus in the end, you'll know what your problem is most the time and it'll teach you patience

 

Thank you guys for the positive responses! As for showing off or being hard on the car, I guess I don’t understand. If the damage is already done, and the car has the proper oil it needs, I would like to still pleasurably cruise the hills. I’m maybe 1,000 miles, it’ll burn half way down on the dipstick..

thanks for the link DK!!

 

It really sounds like your Z is burning oil at an alarming rate. Question for other DE owners: how much oil burning is too much? I know the real answer is "any oil," but referencing the DE engines and their common problem, how much is too much?