Hey all,

My 2001 mustang V6 is knocking pretty bad when I start it up, but it then fades away after a few minutes. The knock gets faster when I step on the gas. What do you think this might be?? Its got about 50,000 miles on it, so could be the spark plugs or something more serious? Its never had any other major problems, gotten oil changes regularly..

Please help! thanks!

 

depending if you change the oil yourself or had someone else do it, could be the wrong weight, could be low, check the oil level first. knocking is not good. very serious. possible rod.

 

Knocking after a cold start then fading away is most likely piston slap.You can try holding the gas to the floor and cranking the engine,this shuts off the injectors and won't allow the engine to start.Crank the engine untill you get a pressure reading on the oil pressure guage and release the gas pedal.Quickly start the engine normally before the oil pressure bleeds off.If the sound is still there it's more than likely piston slap.The pistons are worn to the point where they don't ride square in thier bores and make noise untill they heat up and expand.They can run this way for years with out failing,it's just one he11 of an aggravating noise.[:@]

 

Hey thanks alot. Yeah its actually been running like this for a little bit, but I have the time and cash to get it fixed now! Damn its gonna be a pretty major job though huh, pretty much a rebuild? What am I looking at 1-2 grand? I really have no idea...

Thanks again,

 

if you are thinking about rebuilding your v6, you may want to look into the cost of a 4.6 swap.

 

Really consider a new car before you go tearing into a V6 for piston slap.

It's not really catastrophic.

 

my car was doing the same thing except wouldnt really fade away, the honeycomb in my cat broke loose and was banging around inside the cat. but that doesnt sound like its the problem with yr car. just thought id add

 

Sure is annoying! Scares the hell out of me. I hear it's ok but then I'm still sceptical. Although, mine remains too.

 

So when the pistons warm up they should be flush and then it should run a little better?? Well I have the car payed off, I love the convertable... its got 48,000 miles on it. Should I sell it now or take it for the long haul??

Well thanks alot for your help, really appreciate it!

 

my mom had a minivan that did that. We got it around 90000 and sold it at a little over 110000. Any time it was cold, as in winter startups, summer startups.. pretty much sitting overnight, it would do that. Never had a problem with it, never broke down, never stumbled. It was just an annoying cold condition sound.

If you don't need more power i'd say just keep the car and enjoy it. EVERY CAR is gonna have some flaw