hey guys, I havea 1991 Nissan 300 ZX twin turbo with 85k original miles. I have noticed that when my engine is warm it starts to smoke and leak oil from the oil cap. I don't know why this is happening but I need help and I need answers. I figured it would be a gasket issueor maybe an oil pressure issue. Any of your advice would help.

 

I'm not going to try and pry into a vehicle that is two generations above mine, but does your oil cap have a rubber gasket on it?

 

Replace the PCV valve, they are cheap, less than 10 bucks, and make sure you are not over filled with oil. Sounds like you have to much positive crankcase pressure, since your pcv valve is stuck, its venting the next best way it can, at least that's my best guess.

 

These.

 

Yes my oil cap has a gasket which I checked and it seemed to be in good condition. Not only does it leak oil and smoke from the oil cap, it coming from the timing belt area. Not sure if that is oil leaking down and burning.

 

The Z31 is a resistance engine, if the timing belt fails, disaster. So I would say, get the timing belt / water pump kit, like from courtesy Nissan, it will have most everything you need. I would replace the valve cover gaskets too, and the oil pan gasket is notorious for shrinking and leaking over time. The timing belt change is relatively strait forward, you will take a lot of parts off the front getting to the water pump, so you might allow yourself 2 days to do it, although it can be done in 4 or 5 hours(or less maybe ) if you have done it before.

 

Unless you have a well documented service history, you have no idea how long it has been since the timing belt was changed, the reason I was saying change it now, then you know exactly how old it is, and can drive it with confidence. It is a bit crazy to just throw money at a car replacing every component, but there are critical systems that need maintaining, But even still a 30 year old car can be a money pit sometimes, so its best to pick and chose your battles.