Oil Pressure Question

[acc412]

All,

 

I have a '16 Sierra with a 5.3 v8. I noticed today that my oil pressure was dropping from 40 to 25-30 at idle. Then under heavy acceleration fluxuate from 40-60 psi. Since I've own the truck, ive noticed the oil pressure always stays at 40 psi.

 

I have 6K on the truck and am going for a oil change this Saturday. I've checked the dipstick and the oil looks good and is sitting at the right level. Any ideas?

[audioworks04]

It should stay around 40psi under normal operating conditions, but depending on the oil viscosity you are running and the age/use of the oil it will change. As the oil wears over time it will become "thinner" which will cause a lower oil pressure reading. I wouldnt worry about it too much this early as you are probably just barely getting that motor broke in. If you start seeing ALOT of fluctuation or extreme low pressure then I would get it into the dealer to get checked out.

[Uman]

My 5.3 2016 Silverado experienced the same pressure change at the same mileage. I had the oil and filter changed @ 6156 miles and pressure returned to previous levels. You should see a return to "normal" following the service. 6000 miles on 0w20 oil and a small oil filter causes noticeable changes in pressure late in the interval.

[acc412]

Yeah my first oil change is Saturday as my oil life is at 18% so thag may explain it. I did just get done with a 200 mile drive today

[FL335i]

40psi is normal running down the road pressure. The new motors have a weird smart oil pump you can look into, basically it really boosts the pressure with high RPM's. Very important to run 0w-20 Syn Dexos 1 approved oil and a good filter in these engines. In the Florida summer with oil that has some miles on it I normally see about upper 20's psi when idling at a light. Again, hot oil with some miles, in 100*F+ Florida summer and traffic and AC humping. You need an oil change from what it sounds like. I never let the 1st change go over 5k. Then follow the oil life meter, just make sure it's reset every change. I just did an oil change with 9% left and that came out to about 6,900 miles. Being your first change, I'm betting your motor put some wear on that oil.... get an oil change.

[muddkatt]

It has a 2 stage oil pump. Low pressure at low RPM's and higher pressure at higher RPM's. Its operating as designed.

 

Just a heads up and to save you a new post, the volt meter works the same way. You will notice low voltage at times, then when the system determines that the battery needs to be recharged, the voltage will jump up to about 14V.

[TJay74]

Correct, the oil pump is a 2 stage pump. It is setup like this as high oil pressure is not needed at idle so it is part of the gas mileage savings GM is using to met the EPA requirements.

[Black02Silverado]

As posted on another thread by Southern_Sierra,

 

"Advanced Oiling System

 

The oiling system incorporates a new variable displacement two-stage vane-type oil pump that enables more efficient oil delivery, based on the engine’s operating conditions. Its dual-pressure control enables operation at a very efficient oil pressure at lower rpm, and then delivers higher pressure at higher engine speeds.

 

An oil control solenoid valve, controlled by the Engine Control Module (ECM), mounted to the oil pump provides two-stage functionality. The oil pump is mounted on the front of the engine block and driven directly by the crankshaft sprocket. The pump rotor and vanes rotate and draw oil from the oil pan sump through a pick-up screen and pipe. The oil is pressurized as it passes through the pump and is sent through the engine block lower oil gallery.

 

Pressurized oil is directed through the engine block lower oil gallery to the full-flow oil filter and then to the upper main oil galleries and the valve lifter oil manifold assembly.

 

An oil passage at camshaft bearing location permits oil flow into the center of the camshaft. Oil enters the camshaft, exiting at the front and into the camshaft position (CMP) actuator solenoid valve. The CMP valve spool position is controlled by the ECM and CMP magnet. When commanded by the ECM, the CMP magnet repositions the CMP actuator solenoid valve spool directing pressurized oil into the CMP actuator to control valve timing.

 

dexos 1™ Engine Oil

 

TIP: Failure to use the recommended engine oil and correct viscosity or its equivalent can result in engine damage not covered by the vehicle warranty.

 

The dexos1 specification was uniquely designed to complement the exacting requirements of GM’s advanced engine technology. The specification has gone through an extensive developmental and testing process. Only those oils displaying the dexos1 trademark and a registered trademark logo on the front label of the container meet the demanding performance requirements and stringent quality standards set forth in the dexos1 specification.

 

SAE 5W-30 is the required viscosity grade for the 4.3L engine.

 

SAE 0W-20 is the required viscosity grade for the 5.3L and 6.2L engines.

 

DO NOT use other viscosity grade oils such as SAE 10W-30, 10W-40, or 20W-50.

 

The engine oil with filter capacity has increased significantly from model year 2013 to model year 2014.

 

This also includes 2017 models as nothing has changed."

 

So the ECM controls the oil pressure and this is why you see it fluctuating so much. Nothing to worry about. The general rule of thumb has always been as long as you have 10psi of pressure for every 1,000 rpm. On a cold morning I have seen my oil pressure go up to 70psi.

[Rolling Thunder]

Some years ago Ford changed their dash oil pressure gauge to not move because too many
uneducated owners complained that their gauge dropped "too low" at idle (in the 10 - 15 PSI range)
which was perfectly normal as Black02Silverdo explained. To alleviate these frivolous complaints Ford

made their oil pressure gauge needle almost stationary near the half-way mark.

[sdeeter19555]

Some years ago Ford changed their dash oil pressure gauge to not move because too many

uneducated owners complained that their gauge dropped "too low" at idle (in the 10 - 15 PSI range)

which was perfectly normal as Black02Silverdo explained. To alleviate these frivolous complaints Ford

made their oil pressure gauge needle almost stationary near the half-way mark.

Dodge had a similar "fix" for diesel owners that questioned the oil pressure fluctuating...more or less it was turned into a glorified idiot light (read 40 psi if it sensed oil pressure, read zero if it sensed no oil pressure). The later trucks had a oil pressure switch, that fed the ECM with a presence/absence of oil pressure, the ECM then made the gauge move based on engine parameters (RPM, load, etc.).

 

As far as I know, Dodge oil pressure is still based of a switch and ECM inputs, there is nothing that relates actual oil pressure to the reading on the gauge.

 

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