4.6L Compression Testing...
 

Alright, guys... you probably haven't seen me in here before because I hang out in the 7.3L and Super-Duty section of the threads. I'm kinda ignorant when it comes to gassers so I need a little help. I have a buddy who has a 4.6L in his Crown Victoria (it was an ex-cop car and was regularly maintained)... it's not an F-150, but it's the same motor. Anyways, he's noticed that in the past 3000 miles, it's used up over a quart of oil. It's got 145,000 miles and it doesn't smoke (at least, not enough to be noticeable)... we're gonna check out the cooler first to make sure it's not leaking oil into the coolant, but if not, we're gonna do a compression test. I found a pretty good writeup on testing the compression here, but I would like to know what "within specs" is for little or no oil consumption... I know each cylinder should be within 10PSI (or 75%) of eachother, but even if they were, they could be weak enough to burn oil. Any info I could get off y'all would be appreciated! Thanks, guys!

What I got from AllData. The indicated compression pressures are considered within specification if the lowest reading cylinder is within 75 percent of the highest reading.

A quart in 3000 miles really isn't a whole lot of oil use, especially with 145000 on the clock.

Just confirm there's no leak and drive on.....