Hey all, I'm a forum newbie (joined maybe5 minutes ago) and I've got a question for those brains in your aluminum heads. (I promise I won't make any more terrible engine puns)

I've had my '96 Z28 since February of this year, and it has about 240,000 km (~150,000 mi.) on entirely stock everything. I mean, I've got a K&N filter, but...

Anyway, ever since I came back from a road trip a few days ago, I noticed a pretty high-pitched, sharp squeak coming from under the hood while idling. Before I get a mob of people screaming "BELTS!!", I'll tell you that that's what I first thought too - I mean, that's usually what's gonna be squeaking, right?

While driving, I noticed that it sped up and became higher-pitched with engine revs until about 2500 when I couldn't hear it anymore. And after several shots at running the car with my head hanging over various parts of the engine bay, I'm pretty sure it's not the belt, but instead sounds like it's coming from under the driver's side valve cover somewhere.

I'm a little mechanically inclined, but I haven't tinkered with this car or engine really at all. So after deciding that it would be ridiculous for a valvetrain part to make a squeak (almost a chirp) like that, I started to wonder if it's maybe a loose spark plug.

To make matters worse, I'm in the middle of a move to a new city, right at that stage where half my stuff's in one place and half in the other, so my access to tools and, you know, time... is a bit limited. Any input is appreciated. Also, opinions on whether it's a good idea (or at least not entirely stupid) to drive the car one last time for about 300 miles to complete the move before looking at it/having it looked at/parking it until March.

 

What I suspect, as I seen this happen several times, with the amount of ,miles on the engine, things begin to wear out. What I am thinking is that the roller on one of the valve lifters has gone bad and is sliding on the cam instead of rolling, and is making a screeching noise. If this is what happened, the bad lifter has damaged the cam and both will need to be replaced.

 

Thanks, Pete, for the quick reply. If that's indeed the case, it picked a horrible time to do this. [:@]

Seeing as to how it very recently cropped up, do you see it as something that will become a major drivability/operability problem in the next few hundred miles? All I've got to do is drive it to where I'm moving, and then I can park it. I'll probably have to wait until spring to fix it anyway, as my plan was to buy another car for the winter. I had plans to rebuild the engine in spring as it is, so I really don't want to throw money at it at this point.

I know it's never a good idea to keep driving when you've got a problem, because you can of course make it much worse. I just need some opinions on whether it'll make it 300-400 more highway miles, or if I really need to put off the move and get this fixed. What's this probably going to set me back, assuming about $120/hr [:'(]for labour and replacement with stock GM parts?

 

If what I supect is reallythe case, then the damage has been done. The most that the can happen now is that the cam lobe gets totaly chewed up and now you have a dead cylinder. The other 7 cylinders should get you where you want to go,There are probably metal shavings floating about, but the oil filter should catch them. But the engine is ready for a rebuild anyway.

 

Okay, thanks again Pete. This is probably the first "not-all-bad" news I've heard all day.

 

I once drove a 4 banger running on 3 cylinders almost 400 miles before giving it the proper buriel at the local yard. Hey, it got me home, that's all I asked. Through the mountains mind you! You should be alright. Watch a shop say something crazy like a strut. You're like, "But my Motor screams!" and the shop is like, "Well what we did, was we looked a little further into it, and werealized thatthe sound you are hearingis your right rear strut and a hole in quarter panel that whistles." lol Sorry,shops usually try toscrew me over and sometimes I hear outrages things.

 

Hi all, I'm back to bring up an old problem of mine. The first post in this thread details what I was experiencing, and the second one has what our good friend z28pete thought to be the problem.

Well, I parked & tarped the car over the winter, and got it back out a few weeks ago. This squeak/screech wasn't present when I first started it up, and only came back after two or three bouts of hard driving (WOT, shifting at 5000, that fun stuff). That's when I remembered the problem, and very delicately drove home.[:'(] One thing I'm surprised I didn't point out in November was that this noise has always been intermittent. When it's not present, opening up and letting the engine into high revs, even just one little "vroom," always gets it going again.

So this roller that's gone bad, every now and then decides to "come unstuck" for a while? Does that seem plausible? I would've thought that once this thing seized, it'd be done for good.