abber

so Ive noticed since i bought my mustang that on the cold start on the morning there is some knocking/slapping noise from my engine Ive spent days and days looking over forums and researching and it sounds like im not getting enough oil right away on start up due to an oil filter that either dose not have an anti drain bag valve or one that failed. does that sound like a good place to start looking for the source of this start up noise ? and also if you guys could tell me some brands of oil filters that have the anti drain back valves. im so relieved to here other people having this same issue with this motor and im hoping it's not something as serious as some piston slap or something. the motor only has 55k kilometers on it.

cliffyk

My '03 (with the Motorcraft 820S filter) has done that since I got it 3-1/2 and 75k miles ago, as have a number of other cars I've owned of the years.

As to oil filters not having an anti-drainback valves--you would be hard pressed to find one, as most all spin-on filters have them.

abber

so more likely it's piston slap

cliffyk

It's a combination of drained HLAs, and other normal clearances in many other engine components from which the oil drained while the car sat overnight--but mostly it's not anything to worry about...