its always leaked and used oil.and been a noisy engine too.almost sounds like a diesel.recently it started a ticking noise at 170000 miles.i change the oil every 5000 miles.so i changed the oil and changed from a fram to a purolator filter and used lucas oil additive.it really sounds better.more like a sewing machine now.hahahahah.ive always used castrol 10w40.would it be okay to go to 20w50 ? its real hot in alabama most of the time.also should i flush the oil next time with gunk or tranny fluid ?ive read so many different things i just dont know.im thinking the 20w50 would quiet it down more.and with the looser fit of a motor with 170000 miles on it should flow fine.also ive read a lot about isuzus having poorly designed oil rings which causes the oil burnoff.thats why i mentioned the flush.but im leary of doing that.ive also read that the oil passages to the valve train are small and easily clogged resulting in the ticking noise.any input is much appreciated.thanks.

Tranny fluid is not a flush. It is just a thinner hydraulic oil. It doesn't have any more detergents then motor oil since it does not have to deal with combustion gases.

If the lucas+10w40 quieted it down, I would try a run of the straight 20w50 for one interval to see if it helps. Or try a 15w40.

Use the goldeagle, lubegard, or gunk, engine flushes. Follow the directions. Or, use a quart of Marvel or Rislone during your OCI.

thanks for the reply.i will probably try the 20w50 next time.