I have been considering replacing a tired old Dodge 3.3L V6 engine with a lower mileage identical used engine from a running donor vehicle, available for very little, rather than a junkyard engine that I can’t hear run. My vehicle is probably not worth the price of a factory rebuilt long block, but a cheap used engine might be good enough (yes, I’d probably have trans rebuilt while engine is out). I found a candidate vehicle headed for the crusher due to blown transmission, body damage, and terminal ugliness, thus the price fit my budget. Seller claimed engine had been replaced at midlife, current motor only 120,000 miles. Compression test was very good, all six holes were close (145-160psi), and it seemed to run well and smooth, dipstick oil looked normal. However, other signs suggested the car had been abused, notably a major dent in oil pan, no coolant visible in radiator, oil everywhere outside the engine, all six plugs evenly black, odometer didn’t square with what seller had claimed over the phone (and in a peculiar way), and the car was generally a mess. My gut feeling was beware, so I took a pass without burning bridges. But the numbers (compression and price) keep me interested - all I need is a good block and head.
So, the question is…Does the compression data overrule the other signs? Does it confirm the engine was not overheated or otherwise abused too much? I realize that all the “problems” can be explained in ways that don’t affect the block and heads: oil from a leaky valve cover gasket (almost certain of that), coolant just barely out of view (plausible, should have investigated by adding measured amount of water, but didn’t), plugs blackened by a bad O2 sensor. I’m not really worried about the oil outside the engine, oil seals are simple to replace when engine is pulled. It’s the lack of coolant that concerns me most, if the compression is good, is that assurance that any overheating which might have occurred hasn’t had any consequences to the integrity of the block, head, or head gasket?
Anybody have a perspective to offer? Thanks in advance!