Project MJ: Back To Basics

Jeep 4.0 motor with lifter trouble

In the beginning, we were in such a hurry to put the Comanche on the road to help us move that I skipped some simple steps – changing the oil, for one. Yes, it’s a pretty fundamental step to freshen up all of the fluid on any vehicle that’s been sitting for a while. At the time, not only didn’t I have any facilities to wrench on the Jeep yet, my tools were all packed and scattered to who knows where. But before doing anything drastic like pulling the head off the engine, it wouldn’t hurt to go back to basics and try some fresh oil, at least to flush some gunk out. A small piece of gunk was already responsible for a false low oil pressure reading. Could it solve my lifter issue as well?

I forgot how easy it is to work on trucks – no jack necessary to slide the pan under and drain the oil. I’m used to struggling just to fit a jack underneath my BRZ. While it drained, I also replaced the bent pushrod with the new one I’d ordered. After tightening up the bolts on the rocker arms it was nice and tight, not loose like the other one on the #2 cylinder. Maybe I only had one bad lifter after all? Not that it mattered – if I had to replace one, I might as well replace them all if the head comes off, and I bought 12 with that in mind. Then I moved the drain pan under the oil filter and replaced that.

I was tired of getting instantly caked in gunk every time I came within a mile of the valve cover, so I sprayed it down inside and out and cleaned it a bit too. I need some much stronger solvents for a thorough job, but it’s at least a vaguely metallic color instead of black now. I also cleared out the clogged crankcase ventilation valve, which was probably why oil was burping the wrong way up the intake and soaking my air filter. I knew that the valve cover gasket was bad, so just in case this worked I decided that now was a good time to replace it. The old one I scraped off was a good quality gasket, perfectly form fitted to the contours of the underside of the valve cover. It was kind of a pain to remove as a result, but not a big deal.

I cracked open my engine gasket kit, grabbed a new valve cover gasket – and was disappointed. Unlike the well fitted gasket it was replacing, this was simply a piece of cork cut to the vague dimensions of the valve cover. There was nothing to hold it in position while finagling the cover on, and misalignments seemed inevitable. I did the best I could, then reinstalled all of the bolts for the first time since discovering the valvetrain issues.

With the drain plug reinstalled and everything bolted down, it was time to add new oil. I also added a dose of Seafoam to it. Among its many miracle properties is the ability to dissolve oil deposits in crankcases, which is a fancy way of saying “gunk.” I’d run it a fairly short distance so that the engine could feel the Force Seafoam flowing through it, then change it again to get the now loose gunk out of there.

Time for the moment of truth. The fresh battery was weak from sitting for so long, but it still managed to crank the motor over enough to fire. It didn’t sound bad at first, but soon a metallic tapping returned, similar to what I’d been hearing before – the sound of the valvetrain hitting the valve cover. It was quiet at idle, but louder when I hit the gas. A quick run up and down the road to give the oil a chance to clean the engine innards a bit didn’t help, so I parked it.

I could continue poking at it, pull the valve cover and investigate further, but at this point I think I’m going to wait until my friend Jonah can look at it with me. He knows a lot more than I do when it comes to wrenching, and will probably be able to figure out the issue more quickly and systematically than me. It’ll probably be a month or so before we can do that as my life is about to get fairly busy – among other things, the New York International Auto Show with our man Michael Thompson for the press preview days! As a current Jeep truck owner, I’m hoping to get a look at the new Jeep Wrangler based pickup, which is scheduled to be revealed in New York. I’m sure it will work much better than mine so far.

1 comment
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