Oil pressure with engine off

[YBABRAT]

With so many selling their opinions as facts, I decided to post an uncommon bit of info that may help in diagnosis of oil pressure issues.

Unlike most engines a Pentastar should hold oil pressure when engine is off.
Oil pressure should read 20 psi +/- 1 psi.

Checking oil pressure can be done in Acc. Just open apps and start off road pages. Voltage and oil pressure will show their readings.


If oil pressure does not stay around 20 psi, the oiling system has an issue.

Contrary to Baxter, the Pentastar oiling system does have a pressurized charged state for startup.

Sponsored

 

[jadmt]

I have never heard that before and my 2024 doesn't do that..be interesting to see how many other people's 3.6's are holding pressure when off. @alphawolff, @PotterJLUR care to weigh in? as much trouble as mine has been it would not surprise me if mine is screwed lol.

 

[JT23JL]

The engine lubrication system is not an airtight system. I do not see how it can be holding any oil pressure once the oil pump stops operating. My Jeep (3.6L) does not show any oil pressure when the engine is not running.

 

[Badunit]

Unlike most engines a Pentastar should hold oil pressure when engine is off.

I don't know if you're joking or serious. The off road pages appear to hold onto the oil pressure reading from when the key was last on. It goes away when you turn the ignition to on again. There is no pressure when the engine is not running.

 

[58Willys]

Put a mechanical gauge on it and see what that reads with engine off.

 

[daroutergod]

With so many selling their opinions as facts, I decided to post an uncommon bit of info that may help in diagnosis of oil pressure issues.

Unlike most engines a Pentastar should hold oil pressure when engine is off.
Oil pressure should read 20 psi +/- 1 psi.

Checking oil pressure can be done in Acc. Just open apps and start off road pages. Voltage and oil pressure will show their readings.


If oil pressure does not stay around 20 psi, the oiling system has an issue.

Contrary to Baxter, the Pentastar oiling system does have a pressurized charged state for startup.

That is not true, Please provide some documentation or spec to your "fact." In my experience, what is you are seeing is that last reading that the PCM got before it shut down. If you cycle thru from off > ACC > Run then back it will show the battery voltage, temps, but Oil pressure will be 0. Any pressure would be drained off from the many points that are open to oil flow. There is sorta a backflow valve, but it does not retain pressure just keeps oil from draining back from the oil filter. Here is a good presentation on the olil flow in the PS 3.6 https://bobistheoilguy.com/forums/t...nti-drain-back-capability.370071/post-6682856

Also, if the system did for some reason retain oil pressure, what a mess you would have when you changed the oil filter and that pressure was released.

 

[YGBSM392]

Damn, I was really hoping that it somehow held pressure. At least near the filter and cams.

But I was wondering why they would use check valves. Explains the MSRP though. A cardiac check valve is $6,700. Ha!

 

[CorvZ061]

This is very much untrue. Oil pressure goes to 0 when the engine is off. The oil pump is driven by the engine, it only spins and creates oil flow when the engine is cranking or running. Oil pressure is gotten by the resistance to that flow caused by bearing clearances.

The oil system isn’t a sealed system, so it isn’t going to hold pressure without the pump continually pumping.

 

[MarkM]

Are you sure you aren't talking about the ZF transmission? It actually has a small tank to keep some pressure in its passages during the Start/Stop process.

I have watched the oil pressure drop when the ESS does its thing. It takes several seconds for the pressure to drop to zero. When it restarts, the pressure shoots up fast, which you want, but it never holds pressure long term.

If you think about the lubrication system, it is impossible to hold pressure without a pump. I have heard the piston squirters are regulated, but if they weren't, those alone would immediately drop any pressure left in the oiling system.

Even if they stay closed, just normal passages around bearings would cause the pressure to drop to zero eventually.

 

[flyer92]

This is a joke, right?

 

[azjl#3]

This is a joke, right?

This guy^^^^^. You have all been trolled. Unless of course you use amsoil, then I expect you to see about 25psi with the engine off and driver door shut.

 

[CarbonSteel]

With so many selling their opinions as facts, I decided to post an uncommon bit of info that may help in diagnosis of oil pressure issues.

Unlike most engines a Pentastar should hold oil pressure when engine is off.
Oil pressure should read 20 psi +/- 1 psi.

Checking oil pressure can be done in Acc. Just open apps and start off road pages. Voltage and oil pressure will show their readings.


If oil pressure does not stay around 20 psi, the oiling system has an issue.

Contrary to Baxter, the Pentastar oiling system does have a pressurized charged state for startup.

The bearings are "open", there is no way for any engine to maintain oil pressure without the oil pump running. The ECU is showing the last reading before it shut off.

Wait, is it April 1st?

 

[Terrymo]

With so many selling their opinions as facts,

 

[TheNewGuy]

 

[Pape]

Sponsored