My cylinder head cover has some oil on it.

[95se]

Yesterday, when i popped the hood to do some cleaning i notiiced that on top of the cylinder head there was some oil. What could cause this?? Engine doesn't seem to be blown, gas mileage is normal (23mpg) i don't smell oil being burnt. It looks as though its coming through a small nut on top of the front of the engine near the oil fill cap. Unfortantely, I noticed this two days after racing somebody, which I lost to a friggin Neon, for gods sake.

Thanks

[Structure240sx]

the bolt could be a lil loose letting oil seep out.

[NISMOdrift240]

common...its on mine too. its a pain. almost think its a KA deisgn flaw. i just did new valve cover gaskets, and the spark plug ones too, just in case. makes sense to me its all tight now. drove it for a week (after a leak in the valve gasket.......oops). and still there. i never hear of anything like that on the SR, so i think ill switch to it...heehee.

[danejah99]

i 2nd that, i redid the gasket and still some oil leak, but it gets on the manifold, so every now and then u can smell it.

[95se]

I bought this car mainly because i thought nissan built reliable cars, expecially in terms of engines, but a car that has less than 70K miles should not be doing this. I guess I'll buy Honda next time.

[180crafter]

Did you buy new bolts when you replaced the gasket? When I took the gasket off, I noticed the bolts are the type that stretch when torqued down. After taking them out, they will never be able to seal the gasket the same way. This might be the problem.

[Structure240sx]

i never had any oil leak out of one of my bolts. the car has 120,000 mi on it now. and I've pulled the valve over a dozen of times since i bought it last year.

[96_S14_SE]

Like wise on my 96', my gf's 92', and my previous 91' before that. I just did the gasket on my gf's 92 2 days ago, as it was leaking. We got the new OEM one and when removing it I noticed 4 of the bolts were loose and the gasket was in decent shape. I put the new one on anyway just because we had already bought it and I took the time to get it off hehe.

Um no new leaks or old re-occuring ones now. Ive removed mine countless times as well on my 96 and no leaks ever. I dont know what you guys are doing / are getting your gasket from, but it is not a "design" flaw...

Also I dont see how these bolts can stretch. Especially with the minimal amount of torque needed to apply to the bolt to get it sealed.

[nismostreetracer]

I agree.

[S-14boy]

I would just say to tighten your bolts a lil more, mine was leakin about 3 weeks ago, i tightened it and no more leaks.

[neurovish]

those bolts are only supposed to be torqued to something like 5 lbs btw

[UnbelievabLS1]

If the bolts are what's called "torque to yield" bolts, then they will stretch, no matter what amount of ft/lbs you put on them. It's the way they are desgined. Most torque to yield bolts are made of a softer metal, therefore letting them stretch just a lil to create the proper seal, and also to apply a negative pressure on the 2 sides being pulled together. That way, the objects being tightened to each other are constantly being pulled together, that's just how they work. And if they are re-used, whatever you are tightening down will never re-seal properly, due to the fact that the bolts are already stretched, and will not have the same "pulling" effect when re-installed.

[96_S14_SE]

those bolts are only supposed to be torqued to something like 5 lbs btw

69 - 95 in/lbs (spec given in FSM) or 5.75 - 7.9 ft/lbs (converted)

And nothing in the FSM lists that they stretch, or to toss them out upon removal, and use new bolts for the reinstall like it does with other nuts / bolts.... like say the strut tower nuts... How many of you replaced those when installing STB's or everytime you removed them...?

Like I said either the gasket you guys get for the replacement is sub par / defective, or your not doing something right...

[DAEDALUS]

I won't disagree that certain applications use torque-to-yield bolts, but I've never heard of having to replace rocker cover bolts. In general bolts all rely on pre-load (tension) to 1) keep parts together, and 2) develop enough friction to keep the bolt from rattling loose over time. Once a fastener yields, its strength and integrity have been compromised. Except for a short period of strain hardening, a yielded fastener will never be as strong. Every single 4mm bolt, torqued to 5 foot-lbs, can create as much as 1900 pounds of compression between the head and the rocker cover! Given the area of a 4mm bolt, this puts a stress of roughly 103,000 psi on the bolt. Luckily steel has a yield strength somewhere around 150,000 psi, meaning that it will NOT yield. Hence, no need to replace them if you torque them to spec.