L98 high-mileage oil

[WreckWren]

Hey JC,

I see a lot of folks with V8 VEs here are running 5w30, some (primarily people with internal mods) are running higher (from 10w40 - 20w60).
My motor is stock apart from LS7 lifters. It's very high miles (coming up on 300k), but runs extremely well and has been maintained meticulously.
I have no strange noises, performance is great. Starts smooth, runs well hot.

That said...
Oil light on very hot days when sitting in traffic for extended periods, at idle only (goes away on slight rev).
Built-in sensor reads 13.8PSI on (very) hot idle (~700rpm) with 5w30 full synth.
This seems low, however according to the dealer manual, this is within spec (13PSI minimum). Makes great pressure with revs, within spec the whole way.


The question:
Time to switch to 5w40?


Had a quick search and didn't find any definitive info on this specific topic.
Thanks to anyone with info.

 

[vr304]

No harm in switching to something like penrite hpr 10 (10w50) mine has half the kms that yours does and switched to the hpr 10 last oil change and all is well with it only noticeable difference is slightly higher oil pressure

 

[crew chief]

5W-40 is a great choice and worth a look, I always run this grade.

 

[Redline457]

Definitely go with 5W/40 and see how that goes if you still get oil light the 10W/50 won’t hurt

 

[WreckWren]

Thanks for the answers guys, gonna go with the 5w40 from Penrite tomorrow.

 

[07GTS]

could even be the oil pressure switch getting old and reading lower, if u notice it still going lower id prob look into that

 

[WreckWren]

could even be the oil pressure switch getting old and reading lower, if u notice it still going lower id prob look into that

Reading has been very stable when I've logged the readings over the past service period. It's a possibility for sure, though as it's old.
The pressure light doesn't trigger on days under 28°, and even then only in stop-start traffic for extended periods.

If the 5w40 doesn't resolve it I will get a mechanical gauge to double-check (due for oil anyway).

 

[07GTS]

usually the 20-25psi is the norm for LS hot idle, if its triggering the low pressure warning then its very low so keep an eye on it, are u looking at the center digital oil pressure display or is it a scanner ? just some use the calculated oil pressure even tho there is an actual sensor

 

[WreckWren]

usually the 20-25psi is the norm for LS hot idle, if its triggering the low pressure warning then its very low so keep an eye on it, are u looking at the center digital oil pressure display or is it a scanner ? just some use the calculated oil pressure even tho there is an actual sensor

This is when using the electronic pressure sensor the motor is fitted with from factory.
It is within spec, spec shown below.
(running ~13.8psi@700rpm)

 

[shane_3800]

It'll likely be bleeding pressure off in the cam bearings.
Only step up to a 10w-40.
Going higher will just slow the oil down from getting to the lifters and rockers.