This was scanned from my truck's original Owners Guide... your thoughts and comments, please!

 

no 5w20 listed huh? even my 75 has 5w20 there. i think both of the 5w should be good for well over a hundred degrees with todays oils .even though they only list it good till sixty degrees.

 

Concur, gashog! It is quite interesting how these old charts age as oil improves... it's mostly not too useful today.

On a different note, according to the chart, it looks like 10W-30, 10W-40 and 15W-40 (even though it isn't listed) would be perfect for just about all weather we see here in SoCal (except for up in the mountains during winter).

Based on what we know about modern 5W-20's and 5W-30's, they would do well, too.

I guess one could say that anything from 5W-20 to 20W-50 (yikes! Kinda thick ) would work here.

 

i have never seen 10w50 oil have you?

 

Nope! Never heard of it.

 

The original Castrol GTX was 10W-50 back in the 1970s, not a generic name for all Castrol multigrade dinos like it is today. It probably sheared back to 30 anyway. Castrol XL was 20W-40, another obsolete grade, replaced by 15W-40. 15W-40 works just fine here in the mountains in the winter.

It is also interesting that there is a conventional 5W-40 listed. No wonder it is limited to 60F. If you look at the upper limit for the obsolete 20W-20, modern 5W-20 should cover subzero to 90F.

Jim