Piston Slap after not starting in a while? 3rd Gen Coyote

[Mustang Tony]

Hi All,

I never usually get this, however only one other time where I haven't started the engine in long time....like 3 to 4 weeks....let's say 4 weeks. However, when I started up I was getting the clack, clack, clack sound. This is NOT the typewriter tick.

It went away after several minutes (3 to 5 min.) when it got warmed up. Is this piston slap? Is it normal? (Car has 9,800 miles)

Thanks!

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[Skye]

MY22 here. I have not heard any such noises after being off for an extended period, then starting.

 

[AZlb5.0]

When you let the car sit for too long all the oil drains to the pan and out of the pump. leaving very small amount of oil film on the cylinder walls. If you start the engine it’s going to take a second for the pump to prime and start distributing oil.

This has occurred with GTOs as wel when sitting for a long timel. What we do to circumvent the slap is before starting the car we press the gas and clutch pedal at the same time and it causes a crank no start. We do it for 15-20sec which primes the pump and gets the oil flowing.

See if that works next time it should stop the piston slap. It has been proven to stop te piston slap on GTOs.

 

[BigBeed]

For peace of mind after the car sits for a while, I'll build up the oil pressure before I start it. To do this, hold the gas pedal to the floor, then press the start button while keeping the pedal down. It'll turn over for about 8 seconds and stop. If the oil pressure hasn't increased, release the gas pedal and do it a second time. I usually do it twice then start it normally, but some people do it 3 times.

 

[K4fxd]

If it was a clacking sound it is probably a lash adjuster bleeding down.

 

[WildHorse]

I'll build up the oil pressure before I start it. To do this, hold the gas pedal to the floor, then press the start button while keeping the pedal down.

Which is worse than just starting it.

 

[BigBeed]

Which is worse than just starting it.

To be clear sitting for a while for me is storing it for 5 months over the winter.

Cold cranking is about 300 or so RPM with no combustion forces being applied anywhere. Firing up the engine results in about a 2000 RPM spike and big combustion forces being directed at various journals and bearing faces, during which not every part of the oil circuit is necessarily at full pressure.

Will either hurt the engine? Not really, but there must be some reason Ford made it so you could build oil pressure without starting. And like I said its more just form my peace of mind.

 

[WildHorse]

To be clear sitting for a while for me is storing it for 5 months over the winter.

Mine as well. I fire it up, let it Idle, done. For 6 years now. No problems.

but there must be some reason Ford made it so you could build oil pressure without starting

Holding the pedal down is for when the engine is flooded, doing compression tests, yada, yada.

But like you said, if it gives you peace of mind, it's all good.

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