Baldwin, the 3.5 is actually a stroked version of the 3.2. They use the same block (I think) and maybe different heads. Most of the problems with the 3.5 stem from a lack of oil drain holes in the pistons that, if they get clogged, can end up starving the engine of oil. The pistons in the 3.5 are very short for a V6 engine and there really isn't much real estate to put all of the rings on the piston. When Isuzu built the original 3.5's they only drilled a couple of oil drain holes in one of the ring lands and sometimes those get clogged, or they just don't drain enough oil back into the block so the oil left on the piston walls ends up getting burned. Some of the 3.5's, like my original one, burned a LOT of oil. When I got my VX with 35,000 miles on, it burned 3/4 of a quart of oil every 350 miles, or so, right up until the day I had to replace the engine at 130,000 miles.
I ended up buying a brand new Isuzu 3.5L engine knowing that the new engine had more/better oil drain holes drilled in the pistons and it has not burned a drop of oil in the 5,000 miles that I have put on it so far. Unfortunately the original 3.5's had some flaws, and it can really be hit or miss whether you'll have problems with one or not. Some VXers have had great success with their 3.5's whereas others have not been so lucky.
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