[sunny441]

HI guys:

I have a 1995 Sentra with 127K miles on it. I have had the car since about 117K miles on it. In the last six months - I have put in a new front main seal on it. Also it was leaking tranny fluid from the front CV joint - so that was replaced as well. I also replaced the oil pan gasket at the same time!

I live in Michigan and since the weather was cold, I was using a 15W40 oil. I change my oil every 3000-3500 miles. After about 1500 miles the car was little over a quart low and now it is a quart low after 2500 miles. I looked under the car and there seemed to be a drop of oil on the lip of the alternator. apart from that there are no puddles, dripping of oil from the car at any time. I have had 3 nissans and have friends who have Nissans too and i feel it is unusual for a nissan with 127K miles to burn oil?

since there are no leaks - burning oil is the only thing that is possible. Also are there any other places it is leaking oil from. Also if the car is indeed burning oil - what is the solution for this?

cheers

 

[rogoman]

Start the car up, get it fully warmed up and let it idle for several minutes. Now look under the car for any constant drips.

Now at this point, stand behind the car. Have someone rev the motor to 4,000 RPM and hold at that RPM for about 15 seconds. If you see a lot of blue smoke come out of the tailpipe, the motor is burning excessive oil.

You can do a compression test on every cylinder to determine the condition of the motor. If you have some low cylinders, pour about a teaspoon of oil through the spark plug hole and retest. If the compression comes up appreciably, then that cylinder has worn rings.

 

[sunny441]

compression test

Hello:

Thanks for the reply. I took it to the local mechanic and had the compression test done. Cylinders 1,3 and 4 are at 120 and cylinder 2 is at 70, also when the mechanic looked in there - it was a little damp in there.
Any idea what the compression on a good motor should be at? I heard someone say that it should be at 170 or so.

Also any additives or anything to improve the situation.

 

[rogoman]

I dont know the exact specs on the Sentra but I would say on a good motor, the compression should be somewhere in the 170 psi range.

The #2 cylinder is most likely the oil burner. The problem is probably a broken ring. However it could be a leaking valve.

 

[IanH]

Spec is 171 minimum, 199 standard at 350 rpm from FSM.
Yes its high, and yes this has been debated here before, this is correct.