05-18-2005, 01:19 AM
Does anyone know of reasons for rattling and noise in 3.8 V6 engine when idling. When engine is on higher RPM,like over 1000 - 1200 it disappears. I have run engine without the serpentine belt but noise is still there so itīs in the engine. Is there a timing chain or gears on this engine? If there is a chain,could it be so worn and loose that it can make the noise? Car is a 1987 Park Avenue.
05-18-2005, 09:47 AM
it could be your harmonic balancer is talking to you. see if you can move it back and forth by hand.
very common for the balancer to break the rubber bond. with the belt on (or off) see if you can move the pulley (watch the crank bolt), if the outside moves but the bolt doesn't then the balancer is bad.
05-19-2005, 08:26 AM
Harmonic balancer is OK,not loose as far as I can judge,rubber is fine. Noise and rattle comes from inside engine it seems,mostly from top of it but itīs hard to judge where from??? How about my theory about timing chain? Car has run 15k miles and I doubt timing chain has been replaced...
05-19-2005, 08:57 AM
Are these engines known to loose oil flow to rocker arms or something like that? Have had bad experience with older Buick engines that have lost lubrication to rocker arms,causing noise and wear....
here's a part of a post from BILLK :
Some of the 3800 engines had a problem with the balance shafts that made a noise, requiring a tensioner to be installed for the timing chain.
05-23-2005, 01:22 AM
Iīll take the front end apart and have a look at the timing chain! Thanks!
another thing also, i dont know how hard it is for you to get parts but i would change the magnet in the cam sprocket while you have it out (for the cam sensor). it is pushed in the sprocket from the back side. if the magnets are all gone it can cause the check engine light to come on and sometimes cause the car to not start.