# 99 Sentra GXE Oil Leak



## TrevorCast91 (Mar 1, 2012)

I have an oil leak, really bad, cant park it on the concrete or anything because it leaks so much. I replaced the valve cover gasket and am going to replace the little square gasket on the back of the valve cover, but it is smoking and it is smoking inside the valve cover. it is also throwing oil everywhere in the engine compartment. I also noticed while i pulled the plugs to change them that they were covered in oil. Any help appreciated, i was thinking the pcv valve but after hearing how hard it is to change any other decisions that would help and not cost alot to troubleshoot first would be helpful. Thank you


----------



## EvilPotato (Sep 6, 2005)

pcv valve is NOT hard to replace


----------



## TrevorCast91 (Mar 1, 2012)

my valve cover does not have that piece coming off of it with the socket fitting mine is round and idk how it comes off and i heard it was somewhere else and was a pain to get to


----------



## EvilPotato (Sep 6, 2005)

ok, how about this? took me no more than ten minutes to take a picture, take it off, take picture again, put it back on, then reply here


----------



## EvilPotato (Sep 6, 2005)

anyway, about the oil leak, did you mean the tip of your spark plugs (the one that goes inside the cylinder) are covered in oil or the outside part where the plug wires go, if the latter, then most likely it is leaking from spark plug tube seals. check the distributor seal too, that can leak sometimes. i don't know what you mean by little square gasket, if you mean the small square one INSIDE the valve cover, that gasket mostly just helps with oil circulation to the cams and valves and should not cause external leak. and if you mean splashing like oil over the belts, then it is probably the front main seal.


----------



## TrevorCast91 (Mar 1, 2012)

what is the front main seal and it is the later part with the spark plugs i sealed the spark plug tubes and have not checked on it, but yes i mean the square thing on the inside of he valve cover on the back and how do you take the round one out, you did not explain just said that it did not take long, thanks again really helpful


----------



## etepsnewo (Jul 5, 2008)

Trevor,
You just pull the PVC valve out of the rubber grommet that holds it into the valve cover. It doesn't really screw in, it just slips straight in or out. You might have to pry it a bit to get it loose.


----------



## etepsnewo (Jul 5, 2008)

there are several areas on the 1.6L engine that commonly leak oil after the engine gets over 80K or so on it. . . . or if the vehicle is more than ten years old.

1. Valve cover gasket. Symptoms include oil leaking down the front of the engine contacting the exhaust manifold area. Smoking is common when oil contacts the HOT manifold and burns. 
2. Distributor "O ring". Oil seen at transmission end of the head just under the distributor and dripping down in the bell housing / transmission area.
3. Distributor shaft. Oil drips from the distributor Cap but not at the valve cover/ distributor joint.
4. Main crankshaft seal. Oil found EVERYWHERE in the engine bay but heaviest on the passenger side of the car. Lots of oil dripping from air conditioner compressor area and aft on Power steering pump, hoses and belts can even coat the chassis all the way to the rear bumper/taillight area. The seal is located behind the "harmonic balancer" (Large belt pulley at bottom on passenger side of the engine.) 
5. Oil pressure sending unit. Located above and to the passenger side of the engine near the oil filter. these units often develop oil leaks between the metal and plastic components near the electrical connection plug.
6. Rear crankshaft oil seal. Oil noticeably dripping from bottom of bell housing. Possible slipping of clutch.

RVT sealant leaks. Many areas on the engine are sealed with RTV Silicone sealant. These areas can develop leaks as the sealant dries out due to age. These area include. The oil pan, Timing Chain upper tensioner head access panel. Lower timing chain cover. Rear crankshaft seal plate. Distributor retaining U bracket that attaches the distributor to the head.


----------



## TrevorCast91 (Mar 1, 2012)

def sounds like #4 because it gets on the bumper and more on the passenger side and it is all over the car


----------



## etepsnewo (Jul 5, 2008)

The crankshaft front seal is located behind the Harmonic Balancer. It can be replaced with the engine still in the vehicle but will likely take an impact wrench to loosen the bolt holding it on. Last time I got a price for the replacement from a dealer they said around $200 labor, plus parts. That was a few years ago.

Sounds like your seal had worn completely through. If so it is likely that the metal coil spring inside the seal has been exposed and had been rubbing directly on the Harmonic Balalncer's sealing surface. If that happens long enough the metal spring will cut a groove into that Balancer's polished sealing surface. Just adding a new seal may cause premature failure of a new seal if that has happened. The best solution is to replace both the seal and the Balancer if the balalncer is damaged. Also, its best to use a puller to get the Harmonic Balancer off the crankshaft just in case it has not suffered damage as stated preciously. Prying or hammering on it is not acceptable. The flanges on each side of the areas that the belts runs on are rather easy to break. The seal costs around $30 and the Balancer, last time I bought one, was between $150 and $175. Cuation ! You have to be careful and get the correct Balancer. I found that some national Auto Parts stores have a cheaper one listed to fit your engine ( around $100 ) but the problem is it doesn't have the correct area turned and polished where the seal will contact it. Compare it to the old one looking for that before you accept it.

Here is what you will see after removing the Harmonic balancer:
Front crankshaft oil seal leak | Flickr - Photo Sharing!

The Harmonic Balancer is the large double belt pulley attached to the crankshaft at the lower front end of the engine where the oil pan and engine block meet:
Nissan 1.6L Timming marks | Flickr - Photo Sharing!

Hope this helps !
Pete


----------

