High mileage motor thicker oil?

[scott_williams2]

I recently sold my 95 k1500 and bought a 97 k1500 it’s a 350 vortec. No mechanical noises like knocks but the motor has 240k. I know the gauge is right Bc I changed the oil pressure sensor and it helped a good bit on my gauge The pressure seems to be low like 20-25 warm idle and 40-45 warm drivin. I want to improve the pressure what oil would y’all recommend running? I changed it when I bought it with the recommended Castrol 5w30 but I was thinkin making the switch to mayb 10w40 since it’s almost due. I want a oil that is thicker at operating temps but not too thick to cause damage long term or on cold starts. I live in south mississippi so the coldest it gets is usually 30-40 degrees

 

[Supercharged111]

No need for thicker oil in a high mileage engine. My 1500 has 268k and has been around the same pressure as yours for as long as I can remember. My old TBI 350 only showed 30 warm cruise.

 

[Schurkey]

Not a thing wrong with the oil pressure you're reporting. Leave it alone. My K1500 has 15 psi at hot idle, although it's 50+ at higher RPM.

For the record, OEM gauges and sending units are notoriously inaccurate. Verify with a real oil-pressure gauge.

 

[885speed]

Not a thing wrong with the oil pressure you're reporting. Leave it alone. My K1500 has 15 psi at hot idle, although it's 50+ at higher RPM.

For the record, OEM gauges and sending units are notoriously inaccurate. Verify with a real oil-pressure gauge.

Agreed.

Almost 280K on mine and I just run a good quality synthetic 10w30.

My older TBI Camaro is another story, no idea on its mileage since the odometer stopped working before I got it 13 years ago. But I run high mileage 20w50 in it, but that's because previous owners didn't care for it very well and it really does have low oil pressure at warm idle. You should see the sludge in the intake valley...

 

[PlayingWithTBI]

I've been running Mobil1 10w-40 since the new Mr Goodwrench long block was installed over 17 years ago, doesn't burn or leak any oil in 5000 mile intervals. I did blow the head gaskets a couple years ago and when I rebuilt the top end, my pressures @ idle went from ~12-15 up to ~20-25, maybe because of the cam journals?

 

[df2x4]

Agreed with the others, stick to 5W-30. Your pressure readings are fine.

 

[454cid]

...The pressure seems to be low like 20-25 warm idle and 40-45 warm drivin.

What are you thinking your pressure should be? Your idle number is way above minimum spec.

 

[scott_williams2]

I guess I was thinking that it should be higher like maybe driving warm 50 or so. I’m just trying to keep the motor good Bc my 95 pressure wasn’t too much lower than my 97 when it started knocking then smoking I just don’t want that to happen to this truck

 

[98chevy2500SS]

I agree with the others on sticking to 5W-30 oil in the engine. My 97 has 242k miles on it and it still runs just fine on 5W-30 with 15-20 psi oil pressure on idle warm and about 35-40 psi while cruising at about 1800-2000 rpm, seems to be the norm for Vortecs. My 97 only "knocks" (more like the famous Vortec piston slap) when cold but goes away within about 3 minutes, give or take.

 

[RDF1]

Ive always run Delo 5w40 diesel oil in the LS engines. Works good still.
Have almost 500,000 miles on a 6.0 and 340,000 miles on a 5.3. No issues yet.