Engine Slapping Noise

I have a 1995 Buick Century. When start the Buick there is a slapping noise (more like the sound of a broken electric atena noise going up and down)lasting for 5-15 seconds. It goes away never to be heard until I start the engine the next time. Any suggestion on what the noise is? Thank you.


If it’s a sharp click-click-click-clack type of noise it’s probably a bad hydraulic valve lifter that’s “bleeding down”. It takes a few seconds for oil pressure to pump it back up. Does this happen on EVERY start-up or just the first one in the morning?

Does the vehicle have ABS? If so, the noise could be from the ABS pump running it’s self diagnostics.


It happens after the can has sat for a while. But does not occur all of the time. It seems to be occuring more often recently. It is not a fast click…but more slow noise like the sound of an electric antena going down. More of a clunk – clunk – clunk.