Learned something - Oil Pressure Priming

[speedydave]

I'm not sure where to post this, but I saw a video the other day and for priming the oil pressure on a Gt-350. Like if the car has been sitting for a while, or after an oil change. Anyway, I tried it on my GT and it worked.

My car is a 2020 manual, so your results may vary.

The video shows doing the normal start procedure, push clutch in and hit the start button, But in addition, hold the gas pedal all the way down too. Like push in the clutch and floor the gas pedal and hit the start button. The engine will crank for several seconds and build oil pressure, but not start.

After that you can start it like normal, but the engine has been primed.

Similar gt-350 discussion here: https://www.mustang6g.com/forums/threads/engine-priming-after-winter-storage.155323/

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[EFI]

engine will crank for several seconds and build oil pressure

Is it though? Have you measured how much pressure it was actually making?

I've done this when building engines, and before you start it for the first time you're supposed to pull the fuel pump fuse, drain the fuel lines of gas and just let it crank (without starting obviously since there's no fuel) but I've never seen it build any measurable oil pressure on a mechanical gauge. Maybe 1-2psi but that's it.

I can't imagine it's doing much to actually build pressure. It's also not really necessary unless you have a brand new engine as the oil filter is still mainly pressurized from the anti drainback feature most have. All you're doing is putting wear on your starter unnecessarily.

 

[Qcman17]

Oh no I've been starting my car for nearly 5 years without doing this.

 

[speedydave]

My gauge went up to about 40 best I could tell. My engine was warm, I just wanted to test it. I will use this after an oil change in the future. YMMV

 

[EFI]

My gauge went up to about 40 best I could tell.

40 when you started the engine normally, or 40 while you were cranking and priming it prior to actually starting?

Did you see any gain in psi while you were priming the engine?

 

[speedydave]

That was while cranking, it didn't start. It went from 0-up to around 40, i don't remember exactly, but it built pressure on the gauge.

 

[sms2022]

I don’t think it builds that much oil pressure but it does circulate oil around the engine and eliminate air pockets which is very helpful after an oil change or prolonged storage. It takes a couple seconds for oil to get up to the camshafts in most engines. After sitting you may or may not be concerned about the cams running dry for a second on startup. I don’t really believe there is any harm in just starting right up but Since it takes no effort to do this I always do it just in case after prolonged storage.

 

[HKusp]

I did it with the new build on mine. It built pressure. It took several seconds for it to build, but it did build. I don't remember how much pressure it built. I was just happy to see pressure.

 

[JetGray_Mach1]

Nice write up. Its a common procedure for most fuel injected cars. Flooring the gas pedal does a crank but no start on most. I like to start the car then FLOOR IT vrroom

 

[ORRadtech]

Same procedure to clear a flood condition. It's been that way on most cars for years.
Personally I don't think it's worth the effort. Just start the car normally and pressure is nearly instant.
I keep all my cars well past 100k miles. Currently one at 225k, one at 108k and the Mustang is at 103k, all running flawlessly wit no oil usage. Oh, and guess what, I don't prefilled the oil filters either...

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