Hey fellow Jeepsters
I have a 1988 Jeep Cherokee with the 4.0. It's high mileage (285k), but has always ran fine. It recently developed a very light knock under load. The oil pressure consistently read around 40. It was past due for an oil change, so I changed it and put in 10W-40 and a new filter (same brand/model number). Since the oil change, the oil pressure is spiking the first time it starts every day. I leave it overnight with the battery unhooked (has a big draw) and when I go to start it in the morning, it starts, but the oil pressure gauge maxes out and stays around 80 for 15 minutes or so. Then it hits 40 and stays around 40 for the rest of the day.
Also, since the oil change, the knock has gone from being a knock under load, to a knock all the time. It's more of a ticking sound. Sounds like it's coming from the lower, rear engine. Still running ok, this is just concerning, considering I'm out of luck if it craps out. Advice? Guesses? Thanks!!!
I have a 1988 Jeep Cherokee with the 4.0. It's high mileage (285k), but has always ran fine. It recently developed a very light knock under load. The oil pressure consistently read around 40. It was past due for an oil change, so I changed it and put in 10W-40 and a new filter (same brand/model number). Since the oil change, the oil pressure is spiking the first time it starts every day. I leave it overnight with the battery unhooked (has a big draw) and when I go to start it in the morning, it starts, but the oil pressure gauge maxes out and stays around 80 for 15 minutes or so. Then it hits 40 and stays around 40 for the rest of the day.
Also, since the oil change, the knock has gone from being a knock under load, to a knock all the time. It's more of a ticking sound. Sounds like it's coming from the lower, rear engine. Still running ok, this is just concerning, considering I'm out of luck if it craps out. Advice? Guesses? Thanks!!!
it speeds up as the rpms go up, and follows the speed of the engine. it does not go away after 2k. it gets faster the higher the rpms
CF Veteran
Pull the inspection plate off of the bottom of the trans and check the flexplate as well. Mine started as a very light tick and developed into a loud knock. Had 2 shops tell me the motor was shot and I needed to replace it. Did my own inspection and found cracks in the flexplate. Pulled the trans to replace it and could not believe how bad it was. New flexplate...no more knock.
