oil

[mrmallard]

I have 1999 b2500 truck . it has 236,000 miles on it. whats right oil use
for it. I been using mobile one.

 

[Mark_88]

Well, this has been brought up quite a bit over the years and you are sure to get many replies...

If the engine is not burning or blowing oil then use the recommended oil...I think it's 10w30 or maybe even 5w30. You do not, generally, need additives or heavier oil...just change it at the regular intervals and keep an eye on it between changes.

If the engine is burning or blowing oil...you're better off considering replacing or rebuilding it as opposed to prolonging the life of this one with additives or heavier oils...on this, I can assure you I am very familiar...it just doesn't pay in the long run to try to prolong the life of a wonky engine...although it made my life interesting and I met so many new friendly police officers who followed my oil smoke around...

 

[tomw]

If Mobil 1 is doing the job, and your consumption is acceptable to you, I would continue with that. I figured that synthetics are not needed in most applications, so it is a waste of $$'s to put it in and then throw it away at 5-6k miles because you don't know if it is still 'good' or has used up all the additives. You can go to the long change intervals, but won't be sure you have adequate protection of all the gizzards, so I don't use synthetic where it is not called for.
I would use the viscosity suggested by FoMoCo, and change at normal intervals, but it is your choice. I don't suggest the 'hi mileage' oils for the most part where an engine is working fine and not leaking. I fear the additives that are for hi mileage will mess with the seals, and perhaps make them swell even though they are not leaky, and I'll end up with seals that no longer seal sooner. If it is working fine, don't 'FIX' it seems to be a good way to go, IMO.
tom