oil question

[truckguy_69]

i have an all stock 307 in 69 and its got 129000 miles and im runing castrol 5w30 highmilage oil. i was wondering is this the right oil for my truck?

[68 P.O.S.]

I know myself and a lot of others use 20W50.

[68gmsee]

Check your oil consumption. If it's not using a lot of oil after your regular oil change, then you're not hurting anything. However, it's a little on the lite side for summer or warm weather use on a high mileage vehicle.

With that many miles I would stick to a straight 30 weight or heavier in summer and then switch to the lighter 10/30 or there abouts for the winter.
It's a matter of knowing what your motor wants or will operate better with.

[WorkinLonghorn]

I don't know what part of Washington you are in but if you are in the colder regions that would be OK for winter use.Frankly though I'd go with 10-30,or 10-40. Here in So.Cal.we have such mild winters,I just use 10-30 Mobil-1 all year. With a high mileage engine or when I expect to do a lot of desert driving (120+) I tend to go thicker and use 20-50 (Castrol).

[truckguy_69]

i live in the dessert area (eastern/central part) of washington i ran 5w30 all summer so if i run to 10W40 or 20w50 before winter hits that would be a good idea.

[WorkinLonghorn]

Here's what my origional owner's manual says;

[truckguy_69]

ive also got the original owners manual for my truck but never looked in it for the right oil.