Piston slap is common on 4.6 and 5.4 engines. It is caused by just how the name sounds. The pistons wobble and create a knocking sound. It is all because the rings are undersized and until the heat builds in the cylinder to expand the rings you will hear the knock.

You got to remember that the ford mustang is the low budget sports car and not all parts are perfect.

Piston slap will cause no damage to the engine.

 

Thanks for the info., I was starting to think I was going crazy! ....03-04 Cobra do have good internals though!

 

Where you just waiting to hear the answer you wanted to hear?

 

NO! ....my main question was to see if ours have experienced this "piston slap" /and if it was normal...I'm sure others have experienced....maybe I'll have look on other web sites r search more.

Trust me, this noice only happens when cold, been down the 1/4 mile several times...and still all in one piece!

 

No worries.

 

worries...no...your little weapon-yes!

 

My Extreme has noticeable piston slap when you start it. The best way to describe it is, it sounds like a diesel when it first starts. After the Extremes were released in 2002, Saleen actually drafted a letter telling new owners that this was normal.

 

That could also be the oil not being up into the heads upon first start up... its like changing the oil, and during the first start-up, there is no oil and it will be a lil noisey....

 

My old Mach1 used to sound the same way. I figured it was a right of passage to Hp. lol

 

Diesel is a good way to describe it...only on a cold start up! & once up to normal operating conditions, fine...at least you got a letter...love the Saleen!