Dropping oil pressure

[ukrkoz]

A bit concerned here.
2007 Tahoe with replaced oil pump and new oil pressure sensor.
I drive it for about 2 months by now.
When it was colder outside, oil pressure would hover around 40, going down to 35. Which I know is about right.
Now that we hit around 90 daily with crossing into low 100 s, AFTER engine is really hot, pressure stays above 20, but Does not cross 40 anymore. On cold engine, it’ll get up to 40 but then slowly creeps down to 30 or so and hovers around there.
On HOT engine it’s 25-35, depends on RPM.
I have no idea, what oil was put in during repair. Oil level stays put and display says I still have around 35% oil life left, to what I’m sAdele presuming, he didn’t reset oil minder.
A bit worried about this. Should I? I can easily change oil with heavier weight, no harm there….

 

[ukrkoz]

Well, here's that:

Low Oil Pressure at Idle When Warm

I have a 2004 Tahoe with a 5.3 flex fuel engine and I've started to have low oil pressure issues at idle when hot only. When I start the truck cold the oil pressure is at 40psi and will go higher whenever I touch the accelerator. But as the temperature starts to rise the pressure will slowly...

www.tahoeyukonforum.com

I'll just do oil change this weekend and get a good filter. Will go heavier weight.

 

[OR VietVet]

I would not use a different oil weight than what is called for but is your call.

 

[ukrkoz]

Noted. There's no VVT I should be concerned with, right? That is super sensitive to oil grade and I never had any issues using heavier oils on higher mileage engines with VVT.

 

[OR VietVet]

You never said how many miles is on that engine.

 

[ukrkoz]

Around 150K. It drives fine, short of AFM jerks ever so often. I just really don't like how that pressure creeps down.....

 

[Joseph Garcia]

I agree with @PNW VietVet in that you should not arbitrarily change the oil viscosity, simple to increase the oil pressure. If you go that route, the increased oil pressure will also mean reduced oil flow in the same relative proportion. Reduced oil flow will create problems for you engine, as well.

I recommend that you troubleshoot the issue of why a new oil pump installation won't deliver the proper oil pressure at normal engine operating temperature.

 

[ukrkoz]

Ok, so I talked to my man, mechanic and practically a family. He is "in the know" on Tahoes and owned and has one now, about 6 of them.
He told me to worry not. Said that the infamous strainer underneath the pressure sensor tends to get clogged and, as the result, sensor does not always pick up proper oil pressure. According to him, it's pretty common issue.
We ended planning engine flush this weekend+new oil+filter. I'll still do high flow filter, no harm there. He said that this should bring pressure back to normal.
I'll follow on the results.

 

[OR VietVet]

I should have thought of that too. It is discussed here a lot. He is likely right. Should do the screen and new sensor and do yourself a favor, use GM parts and not aftermarket b/s. He will likely feel the same.

 

[ukrkoz]

Sensor is already new. My suspicion is that, because engine had oil pump replaced along with bank 1 cylinder head, there could have been some debris that went into oil and strainer.
I had strainers cleaned on wife's RX350 too. VVT is very sensitive to their condition.