I got a few good answers from my last post (thanks Nistech!) so I thought I would ask about the other issue with my 99 that I've had since I got it. There's always been a tapping sound from the engine just after startup that lasts for 2-3 seconds.
It's more apparent in the summer -- first thing in the morning, or anytime after the car is somewhat warm but hasn't been running for say an hour or more.In the winter, I don't hear the tapping very much on startup, but I do hear a bit of a heavier tap as I accelerate for the first few minutes on cold days, and when it really gets cold (-20C or so), I often hear the tapping even when the car has warmed up at certain revs.
The local dealer suggested I ignore the sound, and claimed they've never seen a valve out of adjustment on a KA24, but I can't help but think that's exactly what this is. The only other possibility I can think of is the timing chain, and this is too much of a regular tapping to be that, in my mind.
The dealers I've talked to have suggested I might have a cracked exhaust manifold... But I don't really think this is the problem.
So I pulled the fuel pump fuse a few mornings in a row so I could crank the engine over without it firing. Every time I did it, I cranked the starter until the oil light went out on the dash, and once I put the fuel pump fuse back in and started it up, there was no tapping at all.
So can this be anything but a valve that needs a new shim installed? The service manager at the dealer here said it wouldn't be worth the money to have them go and check/adjust the valves, but I can't see it taking more than an hour to pull the valve cover and at least check each valve -- am I way off here? I'd like to just have someone check it out, even if it was just to find out they are all within spec.
Thanks again for any input!
99 Alty again, tapping on startup
I too doubt its a shim problem unless this engine has been apart and put back together. Then I could see a shim possible being in wrong. The fact the noise goes away suggest its not a valve shim. What kind of oil filter are you running? factory I hope. What weight oil? these are impotant. Are you sure its top end and not bottom?
Re: (NISTECH)
It's a dealer filter, and their oil, 5w30 according to the invoice from my last change. The filter is a white one with Nissan written in red on it. As far as it being a bottom end noise, I guess that's possible. I've never been able to hear it very well from outside the car when I've had someone else start it, and it's pretty hard to pinpoint where any sound is coming from.. especially when it only lasts a few seconds.
It's a fairly light sounding tap that I wouldn't expect it to be coming from the bottom end.. what would you suspect as thes source if it were something like that?
I don't think I mentioned that the sound usually lessens after an oil change for a few weeks also.
The car's only got 98,000 km on it (about 60,000 miles if my math is right) so I would *hope* there's nothing wrong in the bottom end...
Modified by merc68k at 10:42 AM 11/19/2005
Modified by merc68k at 10:44 AM 11/19/2005
It's a fairly light sounding tap that I wouldn't expect it to be coming from the bottom end.. what would you suspect as thes source if it were something like that?
I don't think I mentioned that the sound usually lessens after an oil change for a few weeks also.
The car's only got 98,000 km on it (about 60,000 miles if my math is right) so I would *hope* there's nothing wrong in the bottom end...
Modified by merc68k at 10:42 AM 11/19/2005
Modified by merc68k at 10:44 AM 11/19/2005
Re: (NISTECH)
Yeah, maybe it's just the chain slapping around for a few seconds... but it's such a regular sound, and occurs maybe 4-5 times a second, I would expect the chain noise to be a much faster tap or more of a grind/rattle... ah well, I'll probably save myself a few gray hairs if I just don't worry about it unless it suddenly gets worse.... but I always have a hard time with that kinda thing