Any reason why a broken motor mount would stop making a clunk noise on it's own? I had an issue with a loud clunk coming from just underneath and forward of the center of my dash, so naturally I thought it was the rear motor mount. Jacked up the car and checked. Sure enough the mount was covered in black fluid (considering its a hydraulic mount). The noise kept going on for a week, and then just yesterday, I noticed it had stopped all together? Anybody have a reasoning for this? I'm still going to replace the mount since I know its busted and have already ordered the part, but I was just curious

 

Maybe it seized up???

 

As the fluid drains from the mount the engine is going to 'settle'. Perhaps as it was settling it made contact with something causing the noise. Now that it has completely settled it is no longer in contact with whatever it was hitting against.

 

yeah, that definitely makes sense, but im slapping a new one in on friday night so no worries!