My dad has an 01 Chevy Tracker v6 4wd. It smokes when starting intermittently, not all the time. Sometimes it is fine for several days and then once in a while it smokes bad. I would think if the rings were bad or something like that it would smoke all the time. Any suggestions?

 

It's either rings or valves. Here's how to find out which. Pull the fuel pump relay. Pull all six spark plugs. Do a compression check (throttle wide open) and record the values. Do the compresion test again but this time add a tablespoon of engine oil to each cylinder first. If the readings from the second test are meaningfully higher than the first you have bad rings. If the readings are virtually the same you have bad valves. The tablespoon of oil will temporarily seal bad rings causing the compression to increase. If the dry compression results are above the minimums you probably have bad valve seals. I wouldn't worry about that.



These are the minumums for a 2001 V6 Tracker engine.