380SE Rattling Metalic sound from near Radiator
 

My 84' 380SE (250,000km) has developed a "Rattling Metalic Sound from near OR around the radiator area". I have alwready exchanged the "Fan Clutch" with a new one(that was what my Mechanics diagnosis was) & the sound still persit's! The rattle is RPM related (but not "high RPM" related)ie. when in "D" standing at a stop & I shift to "N" the RPM increase & so does the rate at which the "sound rattles", however whilst driving the rattling sound seems to remain quite "static" or the same at typical driving speeds from around 40km's/hr & above. I have checked to see that nothing intrudes into the cooling fans path(it is clear)as it rotates. I wonder what you or anybody else might think? Could it be Alternator / Air Cond. / Water Pump related ?

If you have ever had an in home cooling fan that you turn on in Summer to keep you cool(the ones with the round surrounding metalic "guard" protecting the fan rotation from us),the sound is similar to that of a Fan blade striking the "guard". It makes a rattley "pinging" sound. But as I have just mentioned, my Car fans rotation path is clear.

Also might I add when the Car is started from "cold" the sound does not occur but seems to develops about 2 mins after driving has commensed. By the way the oil psi, water temp, & pressures are all normal as the rattle occurs? Also under acceleration the sound is not evident.

Thanks for any help

Gary (Sydney Australia)

RE: 380SE Rattling Metalic sound from near Radiator
 

your fan is made of metal, and this is where the sound is transmitted to make that clink/clank noise.

the fan clutch is mounted directly to the water pump.
is the water pump a bit loose when you move it?

many of these models got the same noise.

to avoid confusion, use the mechanic's stethoscope to locate the noise.

RE: 380SE Rattling Metalic sound from near Radiator
 

Hey Gary, I had the same problem and I went through the fan clutch and the water pump but it ended up being the belt tensioner. Replaced that and is all quiet now. Hope that helps