Oil leak update.... Technical Ninja? (others welcome of course)

[Guest bastaad525]

Hey dude just wanted to see what you thought. Been driving the Z a lot lately and closely monitoring my oil level to see how badly it's still leaking after replacing the pan gasket.

 

After about 400 miles, I had to put a bit less than 1/4 of a quart in it to bring it back up to full. To be exact, I opened a new bottle of Mobil 1 and poured out enough to bring the level to the first line on the bottle... that may be like 1/5 or 1/6 of the bottle I dunno, I think the line says 800 but I've no idea 800 WHAT....

 

Not all of that is due to the leak, as I also lose a little oil thru the turbo, at least, I get a light coating of oil in my intake pipes. Also, I run open breather filters on the crankcase and valve cover, and some oil does come from there as well, I get a bit of blowby smoke after hard driving, and usually have some oil and dirt buildup on both filters after a couple hundred miles every time I clean them.

 

So in your oppinion is that excessive? My '91 Sentra has NO oil leaks that I can find and I have to put about 1/4 quart every 1000 miles.

[b__sosick]

maybe you're burning oil and not leaking it (in your sentra...)

 

:]

[Thumper]

I don't know if you knew this but every engine burns oil. Even a properly broken in new engine will burn alittle bit of oil. The reason the oil dipstick doesn't move is because water molecules go into the oil and fill up the space the loss oil left. So alittle burning of oil is healthy for lubrication. A 1/4 bottle for 1000 miles on the sentra doesn't sound to too bad, not perfect but nothing to worry about. About the z I would track down the missing oil. My main concern would be the oil in the intake tract. Just make sure you know where it is coming from. Then make sure there are no engine leaks when it sits overnight. If those two are in good shape then you might consider hooking up the crankcase and valve cover. If you are talking about the crankcase pcv line and valve. I have heard of people with leaks when they are not running theres and when they hook it up the leak goes away. Don't forget at idle there is a vacuum in the intake manifold so it will suck the gases out of the crankcase. And the 800 stands for 800 milli liters. So about 4/5 of a liter. Good luck

[Here comes trouble]

had an engine that always needed a lttle over a half quart which I fed it....seems this engine naturally blew off a half quart and after that no oil consumption..Took me four years to realize that and lot of oil wasted. The turbo will burn some oil as the oil wears out.

[zbuild]

I have heard that any oil into your inlet manifold/engine if running a turbo on your engine is a bad thing. ..can lead to pre-ignition. . .especially if you are running higher boost (10+ psi.)

When I set mine up I routed my breather hoses (both tappet cover and block) to a catch can that collects the wayward oil vapour and re-routes it back to the sump.

I would be concerned if my inlet hoses were getting a fine film of oil over them. . . I'd be looking at the turbo seals.

Just a thought

Cheers - Zbuild

[Guest bastaad525]

I thought a little bit of oil film in the intake tract was normal? I thought it was normal that some small amount of oil makes it past the turbo seal and would coat the inside linings of the intake pipes? I know I've brought this up here in the past and was told that is normal

 

The turbo is the one thing on this motor that hasn't taken a crap on me yet, please don't tell me now I have to be worried about this too??

 

It's a VERY small amount, just a light film, not droplets or anything. I can't even THINK of replacing my turbo right now.

 

 

Well anyways the whole point of this post is that I KNOW it's got a leak. I'm talking about the 240z. I'd been trying to get rid of this leak for ages, I had the transmission removed and completely resealed, new front and rear main seals on the engine, and gone thru several oil pan gaskets, but always had this damn leak.

 

Well turns out it might be the rear main cap side seals or possibly a small plug at the back of the engine, neither one of which I have the time or means or the WILL to screw with right now, so was just wondering if 1/5 of a quart in 500 miles would be considered a 'bad leak'? I mean of course to everyone it's different, so some may think that is really bad and some may think it's not bad at all *shrug*. I know when my pan gasket was bad it was more like 1 quart a week/200-300 miles.

 

I know my engine does burn a bit of the oil as well, the rings I used to rebuild the engine with are apparently not that great, as I've had some blowby from day one (noticed as smoke coming from the valve cover vent), yet I dont get any smoke from the exhaust or any oil on my spark plugs, and compression shows good. As I said, I really can't tell just how much of this oil consumption can be blamed on just this small leak, and how much is burning off.

 

 

The Sentra... well as I said I haven't seen any sign of leak on that car, but it does have over 150,000 miles on it so I am not surprised if it is burning some oil. I actually topped it off today for the first time since my last oil change nearly 2500 miles ago and it only took about 1/4 of the quart, which I DEFINATELY don't think is very bad at all.