it uses a LOT of oil. I took it to a shop, and the mechanic told me that it has problems with the oil rings and that it needs a complete engine overhaul.
Lots of possibilities, and I can't argue with a guy who could actually lay his hands on it...but...in MY driveway, I'd be looking at the PCV system (is there oil in the PCV hose? Does the crankcase vent properly without building-up pressure in the crankcase?) I'd look for external leaks (rear main seal? Oil pressure sending unit/switch leaking? Valve covers, timing cover seal, etc. Pull a valve cover (or two) and see if the oil-drainback holes have sludged-over.)
I'd probably cram a set of valve stem seals in place, and while the valve springs were off, I'd check the valve-to-guide clearance by wiggling the valves in the guides. This has to be done with supreme caution and the piston at the top of it's stroke, or you drop a valve into the cylinder which means the head comes off. Seals are inexpensive, can make a big difference. Labor-intensive, though. And
if the guides are wiped, the seals won't last long--it really needs a complete valve job in that case.
I read this article somewhere "as everyone knows IH motors smoke a little when started. There is one easy way to get rid of the smoke. Buy Chevy #427-429 umbrella valve stem seals. There are two versions,long and short. I use the short ones. They slip right in place of the factory...
forums.ihpartsamerica.com
But he also said there might be a lot of carbon buildup on the rings and that driving it regularly might improve that.
Possible. I've used oil-additive detergents on engines years ago. My limited experience was that dissolving the carbon/sludge made for increased oil consumption, not reduced. But that was a long time ago, maybe things are different now.
I don't know the last time the oil was changed. What weight oil should I use? Filter? Additive(s)?
(I've read the threads about engine oil on this forum, but it was hard to get a clear answer. I'm used to working on my 2005 BMW 325, but this pickup is a whole different beast. Any help would be most appreciated!)
Problems with ZDDP ("Zink" or "Zinc") as an additive in oil has been greatly exaggerated. Aftermarket cam companies were sourcing cheap-junk lifters from China; and when they failed they blamed the oil instead of their own greed/faulty parts. Yes, ZDDP levels were reduced in most motor oils; and yes, ZDDP is a "High-pressure" additive. But stock valve springs don't put much pressure on lifters/cam lobes; the lifter diameter of the SV engines is exceptionally large so the loading is unusually light. Oil contamination is a bigger problem than the reduced (it's not eliminated, just reduced) "ZDDP" levels; and that goes right back to out-of-tune engines, and carburetors that don't have properly-functioning chokes and metering circuits, sinking floats, etc. Faulty PCV systems don't remove moisture or volitile gasoline components from the crankcase.
ZDDP becomes WAY more critical when valve spring pressures increase. And ZDDP is not the only high-pressure lube that can be put into oil, it's just an inexpensive one and therefore popular.
Baldwin or Wix filters would be my preference; and whatever weight of oil is specified in the owner's manual. "Diesel" motor oil is generally dual-rated for Compression (Diesel) AND Spark-ignition engines...but so-called "Diesel" oil has very high detergent to remove soot from diesel combustion--which tends to remove the ZDDP layer building-up on the moving parts. It's a balance--more ZDDP to promote a sacrificial film on parts, but high detergent acting to remove that film. In your case, sounds like the engine could use some extra detergent in the oil, so "diesel" oil may be a good choice.
