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Well, a couple days ago I was going to change the oil in the sr20, and upon removing the oil fill cap, I saw vapors coming out and a very definate gas smell.:( That can't be good... I have had poor gas milage for a while now (about 20-22 mpg, mostly city driving and not lead footing it everywhere) but I figured that was probably due to the O2 sensor. I have no idea how old it is.
Here is what I know so far: About 6-8 months ago I had a compression and leakdown test done, and it the compression was within spec (3 cylinders were 175 and one was 180) with no major leakdown problems. The cooling system held pressure too. I have had issues with the car burning a lot of oil at one point, about .5 quarts every 500-800 miles, but that seemed to stop on its own. Also, the PCV system is working (new valve) and I can't see any evidence of a leaky injector (I turned the ignition on with the spark plugs removed and didn't see any gas pooling up on top of the pistons).
Not that its necessarily related, but I have the typical startup clatter even if i let the car sit for just an hour or two. I remember feeling that on most other peoples cars it only happened if it sat for several hours or overnight. The reason I mention this is that twice before I have had some startup-clatter-type noise only about 5x-10x as loud and just as temporary. Scared the crap out of me, and I don't know what it was or what caused it. The engine also has a new timing chain tensioner, and after pullling off the valve cover tonight, it looks like everything is ok. The timing chain guides seem like they are in good shape, and the tensioner plunger is extended.
Regarding the gas smell in the oil, could one or more of my valve guides or seals be shot? Is there anyway I can really tell? What else would cause this?
Oh, something else that struck me as odd: When I had the valve cover off, the exhaust valve springs, the spring retainers, and the immediate area seemed noticably darker and dirtier than the intake valves/springs. Is this typical? (here is a picture: http://www.luminus.cx/pics/unlinked/valvetrain.jpg)
I also pulled my intake off to look inside the throttle body. I cleaned it before, but its all gummed up again, and I can also smell a hint of gas in the oil gum left in the bottom of the intake manifold.
Does anyone with more experience with these engines have any idea what could be causing this? Any help is greatly appreciated,
hmmm, well it sound like a number of possible things. first off, if the oil is all tarred up at the top(i.e. dirty on one side and not other) it could be the oiling tube that runs above that side is gummed up and not providing oil neccesary to lubricate the cam, thereby generating extra heat and burning the oil up that gets to that side. which brings me to the timing chain tensioner noise. 5-10x as loud you say? could be a spun rod bearing. between the top end having what i would say oiling issues, and that noise you say is a loud chain tensioner, it really sounds like a bearing issue. when i pulled apart my motor that had a bad bearing, the top end was filthy, like fricking stained black. and of course it make tons of noise, real bad at startup, then wouls quiet down after it got a little bit of oil in the bottom end bearings. who knows, it could be something else though....how many miles are on this engine? it looks just plain wasted, i hate to possibly be the bearer of bad news. it also looks like you didn't change your oil frequently. best of luck man, i would say it's time for a VE
hmmm, well it sound like a number of possible things. first off, if the oil is all tarred up at the top(i.e. dirty on one side and not other) it could be the oiling tube that runs above that side is gummed up and not providing oil neccesary to lubricate the cam, thereby generating extra heat and burning the oil up that gets to that side.
Yeah, I had thought of that as well. However, I've always run mobil one in it, and (for better or worse) a while ago I ran some STP motor flush through it. The engine sees redline at least once a week, and I autocross it as well.
which brings me to the timing chain tensioner noise. 5-10x as loud you say? could be a spun rod bearing. between the top end having what i would say oiling issues, and that noise you say is a loud chain tensioner, it really sounds like a bearing issue. when i pulled apart my motor that had a bad bearing, the top end was filthy, like fricking stained black. and of course it make tons of noise, real bad at startup, then wouls quiet down after it got a little bit of oil in the bottom end bearings.
That really loud noise is only temporary. When it did it, I immediately shut off the car, then turned it back on and it was gone. Wouldn't rod bearings always make noise?
who knows, it could be something else though....how many miles are on this engine? it looks just plain wasted, i hate to possibly be the bearer of bad news. it also looks like you didn't change your oil frequently. best of luck man, i would say it's time for a VE
I've changed the oil every 3k miles with 10W30 and a nissan filter - the engine has actually been taken good care of. It now has about 120K miles, and I picked it up around 88k.
how is your car running, man? how many miles do you have?
I thought a spun bearing = engine failure..but maybe i'm wrong..
Its runs really strong - I just had it on the dyno at the end of december, and it put down 126 ft-lb torque and 127 hp (thats completely stock except for a k&n drop in filter).
The oiling problem has a lot to do with the 88K of maintenance before you got the car. Sometimes synthetic oil when used on a higher mileage car, or any car for that matter, that has had a poor oil change history will break loose sludge that will create oiling problems. This is because of synthetic oils high detergent or "cleaning" capabilities. The flush could have caused the same effect. I suspect that's what happened in your oiling tube.
The oiling problem has a lot to do with the 88K of maintenance before you got the car. Sometimes synthetic oil when used on a higher mileage car, or any car for that matter, that has had a poor oil change history will break loose sludge that will create oiling problems. This is because of synthetic oils high detergent or "cleaning" capabilities. The flush could have caused the same effect. I suspect that's what happened in your oiling tube.
edit: SP
I personally know (and am a friend of) the guy I bought the car off of. He used a regular oil like castrol but I know it was taken good care of.
Anyway, so it does seem like there is an oiling issue on that one cam, but that still doesn't explain why I'm getting gas in the oil?
sounds like maybe your valve seals and guides are worn out? that motor looks like it's had a hard life...if your car were right here in front of me i could tell you for sure
Originally posted by aztecB13SER sounds like maybe your valve seals and guides are worn out? that motor looks like it's had a hard life...if your car were right here in front of me i could tell you for sure
Thats kind of what I was thinking. It would explain the rapid oil burning I was experiencing at one point, and the gas in the oil (if its running rich due to a failing O2 sensor).
I just wish I could find out for sure...
So, if there is actually raw gas getting into the oil, how quickly will that break down the oil? (well, maybe it doesn't matter anyway... :(
Originally posted by aztecB13SER sounds like maybe your valve seals and guides are worn out? that motor looks like it's had a hard life...if your car were right here in front of me i could tell you for sure
I'll have to take a pic of underneath my VC when i put my polished one on...see what you guys think about my car's life. :p
Thanks for everyone's input. I think what I'm going to do is replace the O2 sensor to see if I can help correct the gas milage problem, and then just continue driving it until something happens... :( Because it would probably be cheaper to drop in a newer JDM sr20de than to have it fixed, if the problem is valve guides and/or (possibly) rod bearings.
