I'm relatively new to the forums, and this is my first post, so I hope I'm in the right spot.
My friend has a 87 Sentra - automatic, carborated, 1.6L I believe, with roughly 190,000 km on it. (If it helps, it was probably purchased in Canada.)
Anyhow, the oil cap on it isn't what you would expect of a normal "screw-on" oil cap - instead it's a rubber push-down oil cap. Over time, the oil cap has gotten a bit of play (as it can be lifted up/down without taking it fully off.) So far, it hasn't fallen off, but it does bounce up enough to let oil splash out.
My friend, being the wonderfully non-observative person she is, never really checks under the hood that much, and the oil often built up enough to splash onto the side over the belts and timing belt cover. (Thus a squeak occurred, which I heard, and that's when I first noticed it.)
We did go to Canadian Tire to purchase a new oil cap for the car a number of months ago, and when it was new, it fit very nicely. However, being the older engine it is, it has a decent oil leak somewhere [which I'm also looking for] so she's had to take the cap on/off a number of times since - resulting in the replacment cap becoming quite loose like the original one.
So for this problem, I have two queries.. [note: I have little experience with cars, but I am learning] is there supposed to be any negative pressure holding the oil cap down? And if not, is there generally a better solution to buying new caps?
I should add that I did read another post saying something about a genuine Nissan oil rubber cap doing the part, but want to be sure.
the rubber plug cap is an annoying thing on those engines. I ordered a non nissan one and it's worked fine. if it's popping out or blowing oil out then there may be a plugged PCV valve or something.
There isn't any negative pressure, the oil just isn't "supposed" to come out of the cap when it is on. Like B11 said I would check or change your pcv valve, you might be getting pressure built up in your crankcase and that could cause the oil to come out of the oil cap.
My step-dad ended up tinkerin on it while I was writing the post. What he did was punch a hole in the rubber cap, and stuck an oversized washer into the underside of the cap that pushes out the edges, making it a tighter fit. [He then put a nut/bolt through the hole to hold it in place.]
I was told that my friend's dad replaced the pcv valve and got it all working, but I'll have a look at it tomorrow when I get a chance.
My step-dad and I were talking and he doesn't really see anything wrong with it (now.) He was saying that the rockers were splashing the oil, and if the cap is off or has a gap, then it will naturally rock it.
My question to you guys is, even under strong rpm's, should a "slack" oil cap be able to be pushed up by any pressure? [I remember the slack cap bouncing up occassionally (like 1/8" or more) when the car was idling fast.]
they sell rubber expansion plugs too, I used to have one of those. got it at the hardware store in the plumbing section. worked great, just really hard to get out.
Practically all Acura/Honda/Mitsubishi/Chyrsler (4-cyl) fit Nissan, so if you find one that fits one of those, it should work. I got a cool Unorthodox Racing billet aluminum cap as a gift (from them), so yeah its pretty much the only shiny thing under the hood. If you want like a $65 http://www.unorthodoxracing.com/oilcaps.html oil cap, go with there's for sure!
The cap shouldn't be getting pushed up/out. There still may be a problem with the pcv valve or the rings are worn and there's too much blowby.
I remember going round and round with a guy about the pcv sytem...he swore it was all good. He finally actually checked and the cheapo hose he put on had completely melted. So, don't rule anything out until you check it yourself.
__________________
Nissan Forum Members that have ripped me off/owe me money: Nicholas Smaldone hpi911t@yahoo.com Steven M. Castano wcdbsteve@yahoo.com & stan410@aol.com
187-A Extended Bowery Street__________22 Potomac Lane
Frostburg, MD 21532__________________Sayville, NY 11782 (631) 563-1292
Practically all Acura/Honda/Mitsubishi/Chyrsler (4-cyl) fit Nissan, so if you find one that fits one of those, it should work. I got a cool Unorthodox Racing billet aluminum cap as a gift (from them), so yeah its pretty much the only shiny thing under the hood. If you want like a $65 URL=http://www.unorthodoxracing.com/oilcaps.html]http://www.unorthodoxracing.com/oilcaps.html[/url] oil cap, go with there's for sure!
i don't think those will work... b11's have a plug, no threads, it just stuffs in there.
What he did was punch a hole in the rubber cap, and stuck an oversized washer into the underside of the cap that pushes out the edges, making it a tighter fit. [He then put a nut/bolt through the hole to hold it in place.]
Linear Mode
