Originally Posted by psabatinojr

I have a 2004 disco with 82,000 miles that has the EXACT same problem (ticking at idle only when warm, etc. exactly as he described). The dealer is telling me that sound is co I g from the lower part of the engine and likely piston seals or a crank, and either way the eventualality is going to be sell the truck or replace e engine with a new short block. Does anyone else have this experience and know exactly what it is?

Originally Posted by JERobinsonService

How about the engines that rap at idle? I’ve had several late model Discos at the shop with noise complaints. In two cases, dealers told the drivers they had noise from liners moving up and down, and they suggested the motor was about to fail as a result. One dealer actually got the motor hot and heard it rap, at which time he sprayed the side of the block with a hose and the rap went away. He told the customer that was evidence of liner movement.

Actually, it wasn’t. These photos make it pretty clear that late model liners have nowhere to move. The hose test simply showed that the noise went away when the engine block was cooled – in other words, the noise was triggered by thermal expansion.

Steve and I sorted that noise question out on another engine a few months back. On that motor – which had exactly the same hot rap – we found the piston skirts had collapsed in about ten thousandths of an inch. That was enough to make them rock when they got hot, and they rapped good and loud.

On that engine we expanded the piston skirts and refitted the pistons. No more rap.