The Olds started to make a strange sound today, its like a tapping/rattling comming from either the valves or the exhaust manifold. The sound only appers between about 5 and 15 mph. There is no check engine light or anything but something is clearly wrong!

does the clicking etc change acording to engine rpm or vehicle speed?
if it's vehicle speed the factory hubcaps are known to make noises similar....
if it changes acording to engine rpm then you may have an exhaust leak/rocker noise

James

It changes with engine rpm (in normal driving thats the speed I hear it) The strange thing is that it doesnt make the sound when the car is idleing or running at a high rpm and is noticably louder at start up. The best way to describe the sound is that its like a large tin can draging under the car.

...you checked under the car for tin cans right?

Actually as soon as I could I stopped to look under the car to see what was dragging (nothing was) but I felt like a idiot lol.

check and make sure none of the spark plugs have loosened up and then listen around your engine compartment with a rubber vacum hose hald to your ear and the other end near any suspect spots (if your really brave you can have a friend drive the car with you under the hood while listening!--i have done this more than a couple of times!)
good luck!
also can you simulate the sound with the car stopped and loaded up in gear at your normal 10-15mph rpm's---I am wondering if it wouldnt be something wheel related and not engine related-cold brakes will click louder than warm ones, etc.

James

check the exhaust rubber mounts. I had this problem once, and a mount got bent and was rubbing on the floor of the car. Made clanking noises when the engine was at certain speeds.

Its fixed!!!!!!!!!!!! Put it up on the lift in autoshop class and found the starter was loose and maken noice. Put $0.06 into it for a new nut and secured the starter and it good.

thank god for autoshop!!!