Last post on Mar 09, 2013 at 12:02 PM
You are in the Nissan Sentra
What is this discussion about?
Nissan Sentra, Sedan
#1526 of 2065 Re: 1996 Sentra Engine Oil leak
Nov 12, 2003 (3:27 pm)
First, you should really get underneath the vehicle and check for oil from the bottom side of the engine. The typical leak generator on a Nissan GA16 motor is the timing chain cover. I have also seen three Sentras that had a lot of oil all over the rear of the engines. This was later traced to the wrong oil filters being installed allowing oil to leak around the filter gasket.
If there are no signs of wet oil dripping, I would say that your Sentra engine is not leaking oil, but burning it. Most modern engines will gather a lot of miles before the piston rings are the source of oil consumption. The majority of times you'll find that oil will be pulled into the combustion chamber past the valve guide seals either because they have worn or become brittle. Sometimes the valve guides themselves are worn badly and the valve guide seals cannot adequately keep oil off of the valve stems, allowing it to pass by the guide and into the chamber.
Without checking the Nissan specs, the compression check seems low to me.
Nov 14, 2003 (11:20 am)
Thanks for your comment. So you really do think that the compression pressures are low as compared to the standards. So it would mean that all the cylinders leak oil? Or probably the compression test methodology needs to be modified?
But I am not understanding one thing. If I am burning oil at such a high rate of 1 quart per 400 miles shouldn' t the spark plugs foul very quickly? This isn't happening and hence I am confused.
#1528 of 2065 Re: cylinder compression
Nov 14, 2003 (3:43 pm)
Refering to a 1993 Nissan Sentra factory shop manual (the latest I have), the compression specifications are as follows:
Nominal - 178 psi
Mimimuim - 149 psi
Maximum cylinder variation - 14 psi
Now, the biggest mistake made by people performing a compression check is in the set-up. The above specifications are based on the following set-up procedure:
1. Engine at full operating temperature
2. All spark plugs removed
3. Throttle at full open position
4. Cranking speed of at least 300 rpm.
You may want to run your test again if you did not measure the compression using the above criteria. A less than well charged battery, throttle closed, spark plugs in, or engine not hot enough will affect the readings enough.
As to the condition of the spark plug. If you were burning a quart per 400 miles -- I know this doesn't sound right if this were a 1960s motor -- but in newer designs with highly efficient combustion chambers that kind of oil usage may not necessarily show up by reading a plug. However, in GM engines that I've worked on that use that much oil, there is rarely a complaint about plug fouling. Those engines the plugs just look a little darker than normal, in the range where you'd think they are just running a little rich.
If you feel that you didn't get an accurate compression reading, then re-test and get better numbers, I'm sure there is nothing wrong with the rings. It will probably be valve guides or seals.
In all honesty, I have seen 100s of these Nissan motors with 150,000 miles and even more that didn't burn a drop of oil. If you bought this car used I wonder if someone over heated it and scored some cylinders.
Let us know what you find.
Nov 17, 2003 (12:50 pm)
Yes I think I may have the incorrect compression values. Mainly because I had done a rather crude compression test. I had:
1. Removed all the spark plugs
2. Put the compression tester one by one in all the cylinders
3. Cranked the engine the normal way one starts a car i.e. without touching the throttle.
The 3rd point may have affected the compression values. Also my battery is now 6-7 years old, so it may not be the best battery to have the compression test. So I guess I may have to do it again, when I get a chance.
One more thing, my car is right now running fine with 34-35 mpg and normal acceleration except I do see smoke when the car is idling and someone sits inside my car are revs it, there is definitely smoke. I haven't yet seen anything when I am driving and I check my rear view mirror.
I don't know why someone would overheat the engine or score the cylinders, but I did buy the car from a small local dealer so he might have done something, I don't know. Right now, I am afraid to take it to a mechanic to do even a compression test as I don't know for how much they would rip me off and I am a bit short of funds right now... so does someone have an idea how much a valve guide or seal job would cost? Also, at this rate if I decide to do nothing and keep adding oil every 400 miles, eventually would my car break down? Due to what? What exactly would happen?
Nov 21, 2003 (9:04 pm)
It's definitely the valve guide seals. Some older Nissans and Mitsubishis are prone to this problem, which is usually caused by someone not changing the oil often enough. I had a 91 Stanza with the same oil burning problem. It burned about a quart every 400 miles or so, but it barely smoked. Using thicker oil along with oil additives helped some, but this can only be done if you live in a warm climate. Symptoms of bad valve guide seals are: blue smoke when first starting the car, a little visible blue smoke while idling, and sometimes a large plume of blue smoke when accelerating from a stop after idling awhile. The sypmtoms you mentioned mirror these. There is no immediate danger to your engine. As long as you watch the oil level, the car can continue driving like that for a long time. The greatest danger is burning out your oxygen sensors and catalytic converter, and clogging the EGR valve and PCV valve (requiring more frequent replacement/cleaning). But again, that would take a long time to occur. To fix the problem would require a valve job, which can cost anywhere from $400-800 for a four cylinder.
Nov 24, 2003 (12:11 pm)
I guess you have nailed it. What you have described is exactly what is happening. 2-3 weeks ago my check engine light had come on, the mechanic said that it was the EGR valve which was clogged, so what you described above makes sense. I will keep you guys posted.
#1532 of 2065 A long, sad and angry story
Dec 01, 2003 (12:26 pm)
Here is my story. We have Sentra GXE 2000 manual. It was not bad car, and to take care for it for the season to come on 09/23/2003 I drove the car to Brown’s Sterling Nissan in Ashburn, VA, for Fall Car clinic and transmission fluid change.
When I went back to collect the car, the advisor told me that they have broken it – “In an attempt to remove the magnet bolt to drain out the fluid, the technician had broken the transmission casing” she said. “We will fix it as warranty”.
Fine. Three visits to this dealership later (either the spare parts are not there, or something is missing, or they just forgot about me?), on 10/14/2003 the car was back for repair. When I came to take the car, first thing I saw was the upholstery on the drivers seat was soaked with grease and oil! Any way, I took the car for a test, and noticed that there is a problem switching on third gear.
The service manager Tony Beaks agreed that this are real problems, and offered me a to hold the car until is fixed properly, and on a mean while to give me another car. What can I say? I agreed.
So, Tony called the nearby Enterprise office, and told them to give me a car, and to charge the dealership for the rental. He did not mention anything about what is covered, and what – not for the rental period!
I drove the rental car for 22 days! During this period, I did about 5 visits to the dealership, to find out what is happening with our car, and all the time I heard “we are changing spare parts”, or “we are waiting for another spare part” etc.
The car was fixed on 11/06/2003. Well, the upholstery was “cleaned” (how do you clean a carpet, covered with oil and grease?), but the transmission now back to normal.
But, as the top of everything, I ended up with $402 bill for additional insurance for the rental car, that the dealership refuses to cover. I opened a case with Nissan Customer Services, with more than a modest success – seems, the ignorance is the common signature of this people.
So, tomorrow I’ll drive what have left out of our Sentra to the Leesburg Court. Anyone to offer different choice?
Dec 08, 2003 (10:04 am)
i was wondering if i can put se-r/spec-v parts,accesories and performance parts into my nissan sentra 2003-manual...because i want to get the body kit, carbon fiber hood, aem intake, hks headers, pulleys..ect... and all the parts i looked at are for the se-r/spec-v type and i didnt see any for the GXE so i was just wondering if they will fit and work on my car? someone plzz tell me
Dec 08, 2003 (11:10 am)
wont it wind up costing you more to do all those upgrades than it would have if you initially purchased the SE-R/SPEC V?
I am not sure about making any of those mods, you may want to search the web for a specialty Nissan enthusiasts page, or even a specialty Sentra enthusiasts page.
Best of luck,
Dec 09, 2003 (8:46 am)
The body kits and hood should fit without a problem. The engine is a different story. Those parts were designed for the 2.5 liter, not the 1.8. I would suggest you look for parts specifically designed for the 1.8 engine.