High mileage engine oil.

[pms1961]

On 8/5/2026 at 10:42 AM, vtfireman85 said:

Long story short, we have a GM 6.0 that the oil pressure is dropping off, used to idle at 40 psi, now down to 30, it’s not an alarming number, but it is a change. Truck has 180k on it, and I just switched to 10-30 to see if it made a difference, it didn’t. What are the high mileage oils all about and are they worth trying? 

There's a screen type filter under the oil sending unit that can plug up from sludge buildup and cause an inaccurate reading on the gauge.Regular oil changes usually mitigate that issue tho.

[TroyDairy]

On 8/5/2026 at 2:38 PM, Rawleigh99 said:

Valvoline Restore and Protect is some top notch oil that will clean out all of the deposits without clogging the oil filter.   Is it burning oil like a stuck ring?  if so, this is what i would go for.  If not burning it, it may be the o ring.  Either way, go with Valvoline Restore and Protect.  

Look up Lake Speed's Youtube videos on it, complete with dyno testing and oil analysis.  He is a real oil scientist with a degree and this is what he does for a living, so it is not just another opinion.

This

 

That Lake Speed (themotoroilgeek)   Has information on that stuff and verrry detailed 

[New Englander]

I have a 6.0 so I looked at it yesterday. Idle @ 30, increases to 40 off idle. It's been that way since I've owned it. Last 6.0 and 5.3 were similar but I'll keep an eye out for any changes. It doesn't look like fun to get the sump off a FWD especially one that's dripping PB Blaster Surface Shield all over it.

[Rawleigh99]

https://youtube.com/shorts/xRglHB_0nTU?is=qUAMz6ULcJPcIf1l

[vtfireman85]

11 hours ago, New Englander said:

I have a 6.0 so I looked at it yesterday. Idle @ 30, increases to 40 off idle. It's been that way since I've owned it. Last 6.0 and 5.3 were similar but I'll keep an eye out for any changes. It doesn't look like fun to get the sump off a FWD especially one that's dripping PB Blaster Surface Shield all over it.

Mine runs 40 at idle