Rattle

[Motorhome]

Hi,
I have since early this spring a rattle when my 6.2 is in idle and lo revs. The noice disappears at normal cruising speed. I can also hear a "klonk" when I run the starter. After a lot of crawling around I think I have found the cause but I don't know what to do.

1434

This is pictures I have taken lying under my RV. As I understand the part "A" is attached to the crankshaft or the torsional damper and "B" is part of the pulley. By grabbing the belt I can easily rotate the pulley as the two pictures shows. Is that normal?? And if it´s not, what is broken or loose?
Is it dangerous to continue to run the engine in this condition?
I really hope that someone can give me some advice.
Rgds
Nils

[DmaxMaverick]

The damper pulley is worn out. This needs to be replaced, sooner is better. It should have a rubber damper to keep the pulley centered on the hub, and it should not rotate to a metal to metal contact (or you get a rattle).

The starter "klonk" may or may not be related. Check your starter bolts and bracket (attaches at the forward end of the starter, to the block). Many times, the bracket is omitted during a starter replacement, because it is difficult to install. This usually leads to broken starter bolts, or worse, later.

[Motorhome]

Thanks!
So it isn't the torsional damper that is bad?!
I can't see more of the design as my pictures show. I have to get a mirror.
Is the pulley mounted to the damper with small bolts or do I have to loosen the fat bolt and remove the damper too?
/Nils

[DmaxMaverick]

I can't say your harmonic balancer (torsional damper) is good, but the picture and description you provided is the pulley (damper pulley). Both, the balancer and pulley, have rubber dampers (later models, 85?+). The pulley mounts to the balancer, with smaller bolts. You don't have to remove the fan for replacement, but it helps if it isn't in the way.

All that said, yours may be very different. Marine and motorhome chassis applications have taken some strange turns over the years. More pictures and info may be in order.