Hello everyone, I am new to the site but needing some help. I recently acquired an 88 Cutlass Supreme Classic RWD. I took it to work the other day and on the way home (in traffic) it began to act up sometimes. It just happend again. The vehicle was just inspected today & passed with flying colors but there seems to be a loud (Diesel like) noise that comes from time to times. It almost sounds like the lifters or something but then next thing I know it is fine & goes away. It has fluids and this morning it seemed to only make the noise on turns...Seems strange so I am lost. I also have an 85 monte carlo that I was told has a "blow by" and the sound that makes in similar to the sound the cutlass is making

 

no ideas?

 

Valve tap or exhaust leak?

Is it a 307 with 7A heads? Those exhasut tubes for emissions rust away and break

 

The problem is that long-distance diagnoses like this are very difficult without more info. Descriptions of noises are also very subjective - you say it sounds like a valve but someone else may say it sounds like an exhaust leak. My guess is that it's an exhaust leak. Check around the manifolds and pipe connections. Check for rust-out in the A.I.R. pipes where they enter the heads (I assume this is a 307 - you didn't tell us what engine you have). Also, check the A.I.R. pipe that goes to the catalytic converter. This pipe has a silicone rubber hose that connects it to the cat. This is often a source of leakage and noise.

 

Sorry for the limited info, thanks for the help. It is indeed a 307. Just replaced the muffler and the donut before the Cat on Thursday night, they said everything else was fine (of course that's not saying much these days) I'll check out the suggestions starting with the exhaust. Thanks!