Advertisement

Did we get away with murder? Did we somehow run this Jeep super low and oil and come out largely unscathed? With the high iron readings on the diluted oil, I remained skeptical.

After talking with Dr. Randolph about my oil pressure and compression readings, he called a friend who’s familiar with these engines, and told me his hypothesis. It might be nothing, and the engine is totally fine, he told me. But he does worry that I may have compromised my camshaft.

Advertisement

“If you’ve worn through the hardness layer on...the cam lobe,” he said, “you might want to put in a new filter, drive it for a while, and then pull that filter. It will continue accumulating iron until you notice the performance of the engine start to deteriorate.”

“If you’ve worn through it,” he continued, “you’ll be able to tell...it’ll start making iron actually faster and faster if it’s through the hardness layer.”

Advertisement

If running this engine on just a few quarts of oil wore through my camshaft’s hardened outer layer, the engine “is on borrowed time,” Randolph said.

“[The good compression] says it isn’t the bore. You’ve got oil pressure, so [the bearings are probably fine]...all you got left is the cam-lifter interface,” he concluded. “It’s either that or nothing.”

Advertisement

Even a worn cam lobe will still allow valves to close, yielding good compression, Randolph told me. So a compression test isn’t going to pick up a bad cam. What’s more, because my Jeep uses hydraulic lifters to take up valve lash, I’m not likely to hear increased clearance in the valvetrain, since the lifter can accommodate.

So I just need to drive the Jeep and keep sending in samples. If iron contaminants are high and increasing, then I know this engine is doomed. Or at the very least, it will need a new cam.