jpane

Just bought a 92 Z24 for my daughter with a 3.1 engine and 124K miles. Before the purchase it was quiet as a church mouse. Two days in my driveway and the mouse has been eaten by a woodpecker.

The engine is still quiet on startup, but starts making a tapping noise once warmed up. The engine runs fine with no misfires. The noise goes away as the RPM's go up, and comes back at idle. I checked elsewhere on this forum, and found many engine noise posts, most of which dealt with tapping when cold that went away as the engine warmed up. My car is the opposite.

The noise sounds like a lifter, but most lifter problems occur when the engine is cold too and continue as the rpm's go up. Based on other posts I checked the oil and it was clean and a bit overfull, and the coolant was a hair low. There are no apparent external leaks. Its too early to tell if there is an issue with the manifold gasket, but I'll watch the levels closely.

Since I'm new to the 3.1 engine, I was looking for some thoughts from the experts on this forum as to what what could be causing the noise or common issues with the 3.1. Sorry for the title of the post, but I thought it might help me get some responses (lol).

jpane

Thanks everyone for your responses. I appreciate the help

jpane

OK... I added Sea Foam to the old oil, drove about 65 miles and changed the oil and filter using Valvoline Max Life. I drove the car another 50 miles or so and the engine is quiet right now. Maybe I got lucky. I'll be keeping my fingers crossed.

shawnvw

could have also been that the previous driver used a low viscosity oil. It explains why its ok when its cold(oil is slightly thicker when cold).
If its ok now that you've changed the oil, keep using that same oil. If not, try using a slightly thicker oil