Rotella T6 5W40, 5000Mi, 1991 Ford 460 - RV

[MutantGarage]

Running Rotella T6 5W40 for the last couple changes.
It's developed a lifter tick at idle after an hour or so highway driving.
around 65-70 PSI, once there is just a little throttle opening, pressure goes to 80PSI,
the bypass must open since it's a hard limit, maybe at first startup on a cold day I'll see 82PSI.
I've let it idle for over an hour on a 100F day with the AC running, not enough to get the tick.

Thinking of going to the next higher vis, Mobil-1 15W50 is what I'm looking at,
looks like good Zinc, Phos for this older bigblock with that gets run hard on the highway.
Out West on a long climbs , I've had it WOT for over 20-30 mins ( Capitol Reef on I70) or US80 in NV

 

[DoubleWasp]

Looks like it is dancing around at the lower end of viscosity.

The M1 15/50 should serve you well. Your engine doesn't appear to be much of an oil chomper (and I wouldn't expect it to be), so I imagine it will hold grade quite well.

 

[FCD]

That UOA does seem strangely low on Zinc.

 

[Rand]

so the purpose of the thicker oil is to get 80psi at idle?

maybe I'm misreading the post?


FWIW if the engine is making noise at lower rpm at 65psi.. you might have an issue that needs resolved.

 

[MutantGarage]

I'm going to pull the lifters in the fall when it cools down, right now it's about 105F out and pulling lifters from an Econoline E350 is a real bear, I've read it's possible to unbolt the motor mounts and tilt the motor to get the valve covers off. Otherwise it's remove the engine. That's why I did the oil analysis, if I've got to remove the engine, I wanted to know if it's got other problems and I need to get a rebuilt one to replace it.

So it looks tight, no unusual wear, good for at least one more oil change, I'd like to not hear that tick, so going up one grade.
TD