Hi,

I am looking at changing the oil pump on my 94 Trooper 3.2 DOHC engine. My engine began clattering horrendously and fortunately it happened in my driveway, so I checked oil pressure and replaced sending unit and get only a few pounds pressure where I previously got normal. I am assuming that no bearings or oil plugs were blown and the engine still starts and runs smoothly, but the valve train clatter is loud due to low oil pressure.
I am wondering if anyone out there has ever done this without pulling the engine, or has a suggestion for something I may have overlooked in diagnosing my problem.
Thanks.

Mike, without the information about the oil pressure, i would have emphatically diagnosed this as the timing belt tensioner which when it goes makes a horrendous noise as if a thrown rod, and the noise will often disappear at 2500-3000 engine rpm. And i wonder if this still isn’t the problem.

But if you are sure of your diagnosis, the oil pump is behind the timing belt at the front of the engine and should be relatively easily changed out once you remove the timing belt and the oil pan. I haven’t done this on my 1992 trooper, but the only problem i see is perhaps needing a special puller to remove the crank gear; but i don’t know.
You will probably want to do all the other stuff at the same time: timing belt, timing belt tensioner, water pump (it’s there too above the oil pump).

But, from your description, i still wonder if what you are hearing is not oil pump related, but actually the timing belt tensioner.

Maybe you can give more info about the oil pressure. You are measuring only from the dash gauge, or are you using a test gauge. Are you testing only at idle, or at higher rpm ? etc

Finally, i worry if it is the oil pump and your pressure is so very low, that there is internal, bearing, damage at the crank, rods, cams, etc.l

//bc

P.S edit:: aren't you the guy who posts those very complete alldata pages? with that info, this ought to be a piece of cake for you. right? //bc

They say, great minds think alike, and BC's diagnosis is exactly what I thought originally. My oil pressure was never great, but after 120,000 when I bought it, I was not too alarmed. Long story short, changed out the timing belt, tensionser pusher, tensioner pulley and idler pulley along with the water pump, back together and still noisy and low (measured 5-7 lb at 3000 rpm).
OH well, yeah, I do most of my wrenching myself mainly out of cheapness, but I had hoped to find out if dropping the front axle or jacking up the engine is the way to go in working on this. I am worried about the bearings too, but really do NOT want to tackle a rebuild at this time. If I can slip in a new pump then I will pray for better oil pressure....if not, maybe time to adios the trupr.