Oil Weight:

[Captain D]

Hi - just curious to receive opinions on:

Typically, I'll do a fresh oil change in the fall just prior to winter storage using the PenGrade1 (Brad Penn) & at the start of the new season (just in case any moisture set in / collected over those months). But, is that overkill? Would the fall oil be just as good?

If not, totally fine - I don't mind going the Xtra mile in doing a spring change too. Anyhow, my car was @ a body shop for most of the winter, so I hadn't done my spring change yet. When driving it home recently, I had better pressure & amazingly none of my occasional drippage under the pan. Granted, it's cooler / not July heat, so the oil is naturally thicker. But, it got me wondering...

1.) Is it best to do both a fall & spring change? 2.) If so, it seems like it may be beneficial for me to adjust to a thicker weight for the spring / summer. I've always ran 10W-40 in my 383 BB. However, if you feel that a slightly heavier weight would be better, which certainly seems like it would be, what weight do you feel would be worth switching out to?

Thanks in advance for any and all replies...

[flyinlow]

I would think your once a year in the fall would be good. Unless you are driving more than 3-4000 miles a year or using racing oil on the street.

Driving is the best way to remove moisture from the engine. My Charger has an oil temp gauge. It takes 20+ minutes of driving to fully warm the oil.

10w-40 would be the thickest oil I would use ,unless you have large bearing clearances or an unusually high oil temps. I run 0w-40 in my Charger . My son uses 10w-30 in his Charger.

[Challenger340]

There are many factors that can dictate Oil Change intervals, obviously mileage, but also time, thermal cycles from hot to cold, the condition and sealing capability of the engine(condition), tuning, and on and on... which may all contribute to Oil and the additive pkg contained within the Oils degradation
that said,
with limited mileages most classics see then the 'once a season' regime is probably fine.

Weight of Oil used should be determined strictly upon the bearing clearances within the engine itself..... and arrived at by the Oil Pressure readings exhibited by the engine across it's full range of operating temps and rpm's using a given weight of Oil.
Engine 'rpm' can also increase Oil Temps.

While typically thicker weights of Oil ARE rec'd for summer/hot driving conditions to maintain good Oil pressure under the hotter conditions.... some engines may not have sufficient Bearing Clearance to utilize thicker Oils and indeed even Hotter Engine Oil and Engine Bearing Temps can be caused within the Engine...... by the inability of the thicker Oil to flow freely within the tight clearances(thick heat generated from hydraulic viscous friction/lock and Oil Pump bypass)
Remember....
the ONLY way Engine Bearings cool is by the free flow of Cooler Oil both IN to lubricate and OUT again to allow more cooler "new" Oil IN again.

Other factors such as rpm and loads can determine Oil Temp increases as well beyond strictly "water temp".... just say'in here....
don't forget that too "thick" weight of Oil for the Bearing Clearances present within an Engine, while it may look good and "pin" the Oil Pressure gauge.... may also increase Oil temps and harm Bearings(reduce cooling)
conversely,
too thin of Oil for the Bearing Clearances present at higher temps may cause lower Oil pressure readings when HOT, which is of concern for many owners.





A little off topic here but don't forget that:
The "Magnum" or Performance versions of the 383/426 and 440 Engines assembly lines that were "side" lines from the std duty Engines.
and each were fed Pistons from the " A B C or D" numerical racks after measurement... to then provide .0005" more Piston to Wall Clearance....
as well as...
Crankshafts that were ground to the "lowside" of the tolerance spec to provide as close to .0005" (mains") and .001" (Rods) extra Bearing Clearance as possible.... given the Higher Performance intended usage and rpm ranges expected.
While most std duty versions of these Engines "as delivered" saw Bearing Clearances typically in the .002" to .0025" on the Mains and .0015" to .0020" on the Rods.... FINE for getting groceries
because of the "magnum" engine assembly Line changes to both Crank grinding and Piston selection....
the HP version Engines were typically slightly higher Bearing clearanced around .0025" on the Mains and .002" to .0025" on the rods.... built slightly looser to reduce friction and Oil Temps as Chrysler was warranty'ing these performance engines.

Just say'in....
one of the biggest mistakes we see today when the DIY guys purchase and assemble their own engines.... is the belief that .0015" Rod Bearing clearance is "all good" because that's what the "book" says right ? within "spec" ?
And doesn't matter because they have NO way to change the Machining clearances "as delivered" anyways ?
WRONG !  
That is for the std duty stock rebuild stuff.... NOT a HP or Performance intended build !.... and if Bearing Clearances are too tight for the application can result in very high Oil Temps and HOT running Engines for many owners who can't see to figure out WHY their water temp gauge shows HOT in summers no matter what they do ? Timing/Tuning changes... new Rads... more fans... yada... yada... and still shows HOT !
It's the internal BEARING CLEARANCES are too tight you meatheads !

Drive and Test the Engine Oil Pressures observed with a given weight of Oil.... adjust the Oil weight thinner or thicker according to Oil Pressures observed across the full Temp and rpm range.