Thread: B15 Oil Consumption

I've noticed that my car uses about 1/2 quart of oil between oil changes. I was wondering if the B15 SE (SR20DE) suffers from the same pre-cat failure as the 2.5L models do. I did a compression test and got 200-210psi across all the cylinders on a warmed up engine. I do not notice any oil leaking anywhere around my engine and the exhaust never shows any sings of burning oil. I noticed that the the top of the #1 spark plug and the threads are a bit wet with oil every time I check it, but I don't really see any sings of oil leaking from the valve cover gasket. I haven't noticed any decrease in performance.

Are the 2.5L models for this generation the only engines that suffer from pre-cat failure?

My car is a '01 Sentra SE (SR20DE) - 100% stock, 122k miles. Factory header and exhaust are from a 80k mile car (original exhaust was rusted out).

If the engine is not dripping or leaking oil then it is burning away. It cannot be just disappearing!

But why and how is the question. My RWD DET has blowy-by so bad it blows the dipstick out under boost if I don't secure it and it burns oil out the tailpipe from time to time, yet it never loses a drop between oil changes.

This B15 SE runs great and has great compression, yet loses 1/2 quart mysteriously between oil changes. I guess the next step is a leakdown test, but I don't have an air compressor at the moment. I trying to get some suggestion on what might cause the problem.

Coolant level at a nominal amount and no air is in the system? Low coolant = hot engine block = burning oil

Leaky seals can cause oil to go from where it should to to where it should not be. Piston rings, valve seals, etc...

Really though, a half a quart of oil between oil changes is really not that big of a deal, especially at the mileage you have on there. Is the car beat on at all? My G burns a half a quart between oil changes and so did my Maxima. Both have under 100k on them. Engines tend to loosen/wear a little as they get older and will start to burn a little oil. Now if you were talking a quart every couple of weeks, then I would say you have an issue.

Valve seals are also a source of minor leakage around the stems on higher mileage motors (which then burns off some). If you mentioned how many miles this is (4000?) I missed it, but half a quart in even 1000-2000 miles would be of zero concern to me on a stock USDM DE with 122k miles. If you're talking 1/2 quart in 3000 miles or so, mostly that's just likely a little ring wear.

Coolant at normal levels with no contamination, car does not overheat.

I usually change the oil around 3k miles or 3 months (Castrol GTX), whichever comes first.

Pop off your intake hose and have a peek in the intake manifold. One of my cars would run through the Royal Purple but it was slipping through the intake.

Car ran great though and when I switched to Castrol Syntec and it stopped.

Half a quart every 3k is not an issue in my book.

To put things into perspective, Chrysler/Jeep 3.8 engines have problems with excessive oil consumption and the geniuses at Chrysler state that 1 quart "lost" every 1,000 miles is normal. The 3.8 takes 6.1 quarts. Yeah, you do the math.