Can't Get Enough
Join Date: Dec 2000
Location: Erie, Pa
Thanked 0 Times in 0 Posts
why does my oil pressure go to zero?**UPDATE**
Prelim info: 1980 CJ7 with 4.0L just swapped.
I just swapped the 4.0L into the Jeep and have a couple of road outings on the engine and all was well. The longest trip was about 20-25 minutes long with a combination of country roads and a little city thrown in. The oil pressure was actually on the high side, about 60-80 psi. The engine has a lot of power and did not burn or leak oil. I decided to add some Sea Foam to the oil to try to clean the inside of the engine a little. I thought that it couldn't hurt. The next day, Saturday, I take it for it's first off road trip and that is when it started acting up. I drove 30 minutes to the trails and then 3 hours on the trails. Towards the end of the trails, I notice the pressure is down to 20psi. On the trip home, it actually dropped to zero. I immediately shut the engine off and coasted to the side of the road. I let it sit for a few minutes while I tried to call for some help, but couldn't find anyone home. So I fired it back up to see what would happen, and the pressure is back at 40psi. So I throw it into gear and take off. Within 5 minutes the pressure is back to zero. I repeat the process. Turn the engine off, immediately restart it and the pressure is back to 20psi. I drive 2 more miles and repeat. I did this a few more times and I finally get home.
I'm baffled about why the pressure goes to zero and then I turn the engine off and then immediately restart it and it's back up to 20-40 psi.
Could it be something as easy as a clogged screen on the oil pump or am I looking at a new oil pump?