2000 Sport, 4.0, Auto, np231, 69,500 miles
So I found out after doing a bit of research on the stickers on my Jeep that it was a delivery vehicle in NYC. Turns out this may be important. I'm thinking lots of hard takeoffs on a cold engine and ALL city driving for the first 3 years of its life. After that, the guy I bought it from commuted between NYC and DC. That's as much background as I can give on the beast.
So, being paranoid and sitting in DC traffic I had the windows down against a jersey wall a few days this week, listening to the motor. On hard takeoff I get a little of what I originally thought was spark-knock. From being on the throttle and then letting off I get about half a second of the same noise. Couldn't climb out and figure out whether it was coming from the top or bottom end of the motor on the freeway.
Maybe related but maybe not: I replaced the serpentine belt and torqued it to spec two weeks ago but when the engine is cold and I turn the defroster on (AC kicks on) I get a squeak, squeak, squeak from the engine bay. This goes away when the engine is warm. I think I nailed that down to the AC compressor. Watching craigs list for one of those, just in case it goes hairy splat on me.
So final straw: On the way home tonight, I get an idiot light saying Check Guages. I do. Oil pressure reads zero! Knocking is happening. Put her in neutral and rev just a tiny bit and the pressure jumps back to between 10 and 20 when I get to 1500 rpm. Let off the throttle and it slowly goes back down to nuthin. Cold oil pressure is a hair over 40 by the dash guage.
So my question is: Am I going to spin a bearing or send a rod through the block? I'll be changing the oil this weekend and putting on a new filter, anything but Fram from what I read here. It's not a Fram right now. The plan was 10w30 oil unless somebody here says different. I'll also pull the oil pressure sending unit and make sure it's undamaged and cleaned. My real concern though is the short block. I sold the previous vehicle because it started cutting out on the highway and because I had such great experiences with Jeep 4.0's in the past. The wife is going to throw a rod if I have to pull the bottom end and change the bearings in the yard. Can you do the bearing business without pulling the motor on a Jeep?
Thanks in advance, Jim
So I found out after doing a bit of research on the stickers on my Jeep that it was a delivery vehicle in NYC. Turns out this may be important. I'm thinking lots of hard takeoffs on a cold engine and ALL city driving for the first 3 years of its life. After that, the guy I bought it from commuted between NYC and DC. That's as much background as I can give on the beast.
So, being paranoid and sitting in DC traffic I had the windows down against a jersey wall a few days this week, listening to the motor. On hard takeoff I get a little of what I originally thought was spark-knock. From being on the throttle and then letting off I get about half a second of the same noise. Couldn't climb out and figure out whether it was coming from the top or bottom end of the motor on the freeway.
Maybe related but maybe not: I replaced the serpentine belt and torqued it to spec two weeks ago but when the engine is cold and I turn the defroster on (AC kicks on) I get a squeak, squeak, squeak from the engine bay. This goes away when the engine is warm. I think I nailed that down to the AC compressor. Watching craigs list for one of those, just in case it goes hairy splat on me.
So final straw: On the way home tonight, I get an idiot light saying Check Guages. I do. Oil pressure reads zero! Knocking is happening. Put her in neutral and rev just a tiny bit and the pressure jumps back to between 10 and 20 when I get to 1500 rpm. Let off the throttle and it slowly goes back down to nuthin. Cold oil pressure is a hair over 40 by the dash guage.
So my question is: Am I going to spin a bearing or send a rod through the block? I'll be changing the oil this weekend and putting on a new filter, anything but Fram from what I read here. It's not a Fram right now. The plan was 10w30 oil unless somebody here says different. I'll also pull the oil pressure sending unit and make sure it's undamaged and cleaned. My real concern though is the short block. I sold the previous vehicle because it started cutting out on the highway and because I had such great experiences with Jeep 4.0's in the past. The wife is going to throw a rod if I have to pull the bottom end and change the bearings in the yard. Can you do the bearing business without pulling the motor on a Jeep?
Thanks in advance, Jim
atriot: 
