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My '02 vert suddenly developed a loud noise, similar to a collapsed lifter.... while sitting at a stoplight... got so loud, I shut the engine off! Re-starting it, no noise! Now, it comes and goes, intermittently, hot or cold.... sounds just like a hydraulic lifter that won't pump up/bleeds down.....
Of course, all the fluids/oil/etc are fresh and full....
Googling the symptons only comes back with split o-rings on the oil pump causing cavitation in the oil and hence lifter noise...
Any one have a similar experience?
Can you isolate the source of the noise to a specific valve cover or better yet, cylinder? If yes, and it's the same one all the time, thenyou can rule out the oil pump split 0-ring issue. Could it be that you've lost the roller bearings out of a rocker arm? Wonder if you could put a strong magnet on the oil drain plug before you run the engine again, and then look for debris / evidence of bearing residue, when you pull the plug and drain the oil?
Sounds like LH side, front cylinders.... the wierd thing, it's not consistant, started doing it out of the blue, then went away, then did it again....etc......etc......
There's always been a bit of a lifter type noise from that area, very slight, never got worse, never got better, didn't matter cold or hot....(until now)
Last fall, took it to the stealership to get all my warranty concerns addressed prior to the expiration of the GM extended - one issue was that noise, the other was the trans... they claim they couldn't find fault nor issues with either. When I took the car out of storage in the spring, the trans failed big time within a week! The warranty was expired by then, but I raised s%^t with GM, and they covered it... now this lifter noise is getting real bad... but it still runs great... just sounds like a hyudraulic lifter bleeding down....
Sounds like LH side, front cylinders.... the wierd thing, it's not consistant, started doing it out of the blue, then went away, then did it again....etc......etc......
There's always been a bit of a lifter type noise from that area, very slight, never got worse, never got better, didn't matter cold or hot....(until now)
Last fall, took it to the stealership to get all my warranty concerns addressed prior to the expiration of the GM extended - one issue was that noise, the other was the trans... they claim they couldn't find fault nor issues with either. When I took the car out of storage in the spring, the trans failed big time within a week! The warranty was expired by then, but I raised s%^t with GM, and they covered it... now this lifter noise is getting real bad... but it still runs great... just sounds like a hyudraulic lifter bleeding down....
My car started doing the same thing. I am trying to hunt it down now. The Service Manual diagnosis say to check the O2 sensors for water intrusion/damage, check the fuel filter for blockage, carbon build-up, bad gas, etc. I hope someone can figure it out. I am hearing about this problem on a 3 - 4 C5's now.
Typically when a lifter bleeds down it happens when it cools off, not while its running. How's your oil pressure reading at the time it happens? Yes, you could have lost some roller bearings on a rocker, which are easy to replace, possibly a broken valve spring which would need to be looked at right away. If you have a bad lifter, you need to fix it right away. The heads have to come off to get to them. If you replace one, might as well do them all.
My car is totally stock... oil pressure is fine btw.... like I say, the wierd thing is it'll do it intermittently when it's running!!!
I think I have a good vette engine guy available to take a look at it this weekend.... hopefully we'll find a cheap easy fix.. (yeah, riiiiiiiiight)....