When I got my Z, it consumed about 1 quart of oil every 3k miles. I've always used Castrol Full Synthetic 5W30. I've only driven it to and from school and work, no more than 30 minutes at a time. One day I took it to my grandparents house, about a 3 hour drive. Once I got there, I parked it and then I had to move it about 30 minutes later. I started it and a white cloud came out of my tailpipes. I've been monitoring the oil more carefully and recently it's been drinking about 1 quart every 1k miles now. Just recently it ate up about a quart and a half in about 600 miles, albeit it had been 5,000 miles since my last oil change. My thoughts that the oil might have started to thin out after that many miles so I'll see that quart and a half in 600 miles as an outlier.

I'm still monitoring my oil consumption pretty closely. I checked it right before an autox event and then right after. No oil was used, or not enough to see it on the dipstick anyways. For whatever reason, it seems to not like it when I drive it for long distances. Short distances and it's fine. If I drive it for 30+ minutes, park it, then rev it to 3k+ rpms, it'll give a white cloud of smoke from the tailpipes. Not a massive cloud, but enough to be able to notice something is up. Radiator fluid hasn't gone down at all, car stays the exact same operating temp, no matter how hard you drive it. Idles and revs without hesitation, pinging, or knocking.

Pulled the spark plugs...
They are in order from 1-6 in respect to the firing order.













Here is the compression test 1-6 in respect to firing order again...
1 - 170
2 - 175
3 - 181
4 - 172
5 - 171
6 - 176

What are your guy's thoughts? I'm suspecting a valve seal is going out, or multiple ones anyways. If that's what it looks like, will it be okay to run like this until next spring? Only reason why I say this is because I'll probably do the seals over spring break and then add a few upgrades to the engine/replace things while I'm in there.

 

I may have missed it- how many miles?

 

117k, spark plugs were replaced at 100k

 

Did you do a hot compression test or a cold compression test?

 

Warm/hot test. I was driving it and then about an hour after I shut the engine off, I did the compression test

 

Good stuff.. With it consuming that much oil I'd say you're on the right track suspecting valve guides; particularly your exhaust valve guide on cylinder #3. I think that's why the psi. are so high with that cylinder as well, because that cylinder is saturated with oil. As far as it being ok until next year, it's hard to say. Just keep monitoring your oil level, but if it starts to drop substantially, I'd fix it asap. Good luck.

 

Sounds good to me. I was concerned with #3 and #5, mostly #3 though as it looks like it's soaked in oil a pretty good amount. I'll keep checking it and see where to go from there

 

Pcv valve, good chance it needs a new one. Mine did the same thing, I typically burned 1 quart per 5k miles , it make a sudden Jump and it was pcv

 

Checked the PCV valve, looks good I think. I checked the hose as well and it is clean. I shook the PCV valve as well and it rattled. Not sure if that means anything...

 

http://www.dummies.com/home-garden/car-repair/fuel-system/how-to-check-and-clean-the-pcv-valve/

​​​​​​​...not saying you're a dummy, but here.

 

You callin me a dummy! Haha

I actually didn't know you could do that. Nevertheless I just tried it and it had plenty of suction at the valve

 

Long-term update

I'm not active here anymore but still have the car and thought I'd give an update in case anyone ever stumbles across this thread.

Been consistently going through about a quart of oil about every 600-1k miles depends on how you drive it. It had 175k miles on it before cylinder #3 went dead. Did a leak-down test sometime before cylinder #3 died and it had about 30% leak, the other cylinders were less than 10%. Pulled it inside one night and did one last compression test before working on it. #3 had no compression at this point lol.

Not a good start...


Something's missing...




Never got to the bottom end but I didn't have issues there anyhow so I left the rotating assembly alone, cylinder walls looked ok for the mileage I suppose. Just a ton of carbon build-up pretty much everywhere. Notice the wet oil buildup in the middle exhaust manifold, still has factory cats, can't imagine what they look like ha.


Replaced the two exhaust valves and all valve seals. Been driving it for a little while now, original oil consumption problem hasn't been fixed lol. I didn't look into it very thoroughly as the car doesn't mean as much to me as it did 5 years ago, plus it isn't worth much with the mileage on it so I took the cheapest route possible to get it back running again. I suspect the piston rings for that cylinder are in very bad shape or as I was rereading through this thread, Atreyu'z 350 mentioned the valve guides themselves. If it lasts another 10k miles I'll be happy lol.

A thorough look at everything is worth the time I'd say, it wasn't worth it to me in the end with the mileage on it and the time + money it would have taken to dig deeper