Just purchased a 1994 Corvette with a six speed. Car runs okay, some electrical plug issues and the intake was leaking. Got all those thing fixed. Hearing a noise like a pump or a valve opening and closing??? Any ideas. Also noticed that the last owner over filled the oil.I'm see oil coming from the dipstick tube. So I'm doing an oil change next.

 

Uh ho could be a bad bearing in the crankkk. Hopefully it is just over filled.if u hear a ticking noise under the valve covers. Pull em off and see if he had 1.6 rockers in there. 1.6 rockers are notorious for ticking. Check all the pulleys, make sure nothing is interfering or hitting anything that it shouldn't. Listen closely, turn ur car on and if u hear the noise from the top pull off the valve covers. On the bottom. Check the exhaust maybe a leak. If u have a lift its easier.

 

Worse case senerio, piston slap :-\

 

Oil coming from the dipstick tube may not be the result of too much oil........... let's hope it is not caused by pressure into the oil system through a ruptured head gasket.

 

This is what I did when I got my 90 c4. The guy I got it from told me somethin different everyday so I figured he was b/s'n. Since your car is almost 20 years old and u feel its time for a tune up. Save up for a new gasket kit from mr gasket. Take off the heads. Clean whatever u can in the cylinder sleeves & the pistons. Take off the intake. Clean it or port it. Take your time. Pull out the spark plugs they'll tell u what's really going on if u have a guide what to look for. Take out the fuel injectors n replace em if u want to. Look for small things as u clean everything, now if u can replace ur optispark(have fun). Drain the coolant, flush the system. Whenever u do ur oil change look to see if there's small pools of coolant in the bucket. If so that's another topic I'm sure nobody wants to get into. You bought a corvette, a sign of success and markmanship for a individual, best thing to do is treat it with care. And it will last a long time. I replaced ALL my gaskets. Injectors. Spark plugs, fluids(rear also). Took me a good month n half. And I learned a lot about my corvette. Hell I even found an old Channels hardware reciept dated back in 92(remember that store?) Its a lot of work but its well worth it and whenever u drive it, ur gonna feel a load off ur shoulders

 

Thanks everyone for your comments. I've already replaced the intake and valve cover gaskets. The lifter valley was surpising clean. I'm thinking the old owner just over filled the oil because the intake was leaking so bad. Changed the plugs also and they also looked okay. The plugs weren't wet from oil. The car does have alot of miles(163000) and I knew that when I purchased it. Just hoping to get to drive it for a while. Planing on an LS swap. I already have the LS motor and a T56 out of a 2002 SS Camaro to drop in the car.Just not completly ready to start.

 

It would take several qts too much to blow oil up the dipstick...something way worse is going on here.

A. gas being forced to the crankcase (smell the stick)

B. a totally screwed PCV system

C. broken ring glan or holed piston thats letting extreme amounts of blowby in and trying to blow everything else out.

Pull the PCV and see what that does to idle and see if there is much smoke from the case hole.

 

I was just reading somewhere about noisy elctric airpumps in the 90's. Mine is mechanical, but before I deleted it, it made a valve/flutter air noise. Just a thought. Get yourself a mechanics stethoscope, and listen to where it may be coming from. h

 

you could have saved the money from the LS motor and the corvette n picked up a nice C5 z06. theres 2 by me for sale red & a yellow one (RED)-11,000 (YELLOW)-9,500. You'd be getting a "nice" LS6 engine that make a little more hp

 

Well I'm going to check out some of the items that everyone has suggested. There's no hint of gas in the oil. I'm thinking that the noise I'm hearing is air pump related, it seems to quiet down after the engine warms up. As for the oil coming up thru the dipstick this is only happening if you rev the engine up high. I found this when I was attempting to burp the coolant system yesterday. The engine sounds and run good, so I don't think it's a blown piston or head gasket. As for the LS motor it was from an old project that got sold and I wasn't going to let it go. Thanks again for everyone input.