Oil Pressure Craziness and Knocking

[00meangreenXLT]

So I was driving home from school today and I noticed that my oil pressure gauge was going crazy, when I accelerated it started moving rapidly between L and H, just bouncing all over the place. When I was just coasting or just sitting at a light idling, it went to the normal halfway mark and just stayed there as usual. I changed the oil pressure sending switch about 6 months ago, so I figured maybe it was an electrical issue with that, since I had similar behavior with the old switch, so I really didn't think anything of it since the engine was running just fine and not making any noise. Drove about 15 minutes with this happening, no problems. But then I went to accelerate onto the highway, and the oil pressure gauge shot straight down to L, and the engine quickly began making a lovely metallic knocking sound :roll: needless to say I pulled over into a parking lot, and shut it off as quickly as I could.

I Let the engine cool a bit, checked the oil level and it was where it should be and completely clean as it was just changed two weeks ago and has maybe 400 miles on it. Engine temperature was also normal, gauge was exactly halfway between H and C while this was happening. My friend came to help me as I figured I was gonna have to get towed and he has AAA, but I started the truck up just so he could hear the noise and it was gone!!!!!!! I am totally baffled how the engine could be running fine all day, suddenly have no oil pressure and start knocking, then start up 45 minutes later and be completely fine. I ended up driving it home, oil pressure was normal the entire rest of the trip, knocking never returned.

SO I guess my question after this rant is what do you guys think could have caused this? Has anyone had this happen before? I have another car so I'm just parking the Explorer while I figure this out...Thanks for any help or opinions

 

[windsors03cobra]

I would be pulling the oil pump drive/cam synchronizer out and have a look at the roll pin that attaches it to the gear and also look down in the block at the oil pump driveshaft. It is in front where the distributor use to be.

 

[deweyville65]

So I was driving home from school today and I noticed that my oil pressure gauge was going crazy, when I accelerated it started moving rapidly between L and H, just bouncing all over the place. When I was just coasting or just sitting at a light idling, it went to the normal halfway mark and just stayed there as usual. I changed the oil pressure sending switch about 6 months ago, so I figured maybe it was an electrical issue with that, since I had similar behavior with the old switch, so I really didn't think anything of it since the engine was running just fine and not making any noise. Drove about 15 minutes with this happening, no problems. But then I went to accelerate onto the highway, and the oil pressure gauge shot straight down to L, and the engine quickly began making a lovely metallic knocking sound :roll: needless to say I pulled over into a parking lot, and shut it off as quickly as I could.

I Let the engine cool a bit, checked the oil level and it was where it should be and completely clean as it was just changed two weeks ago and has maybe 400 miles on it. Engine temperature was also normal, gauge was exactly halfway between H and C while this was happening. My friend came to help me as I figured I was gonna have to get towed and he has AAA, but I started the truck up just so he could hear the noise and it was gone!!!!!!! I am totally baffled how the engine could be running fine all day, suddenly have no oil pressure and start knocking, then start up 45 minutes later and be completely fine. I ended up driving it home, oil pressure was normal the entire rest of the trip, knocking never returned.

SO I guess my question after this rant is what do you guys think could have caused this? Has anyone had this happen before? I have another car so I'm just parking the Explorer while I figure this out...Thanks for any help or opinions

This may be considered a stretch by some, but if you can, pull the valve covers and see if there is any restriction to the drain holes in the heads. Sounds to me like oil is not draining back into the crankcase fast enough, starving the oil pump. Problem could also be in the lifter vally too. You show a 5.0 on your vehicle specs, which is why I mention the lifter valley.

 

[00meangreenXLT]

Thanks so much for the replies and suggestions! Yes my truck does have the 5.0L V8, and I don't have the tools or expertise to take the engine apart that much unfortunately my dad's friend that's a mechanic suggested that I immediately change the oil and filter...the oil seemed unusually dirty for only having around 400 miels on it. I changed the oil and filter and I've driven about 50 miles or so, and it's been fine....I still don't trust it and I don't want to push it, so I'm gonna hold off driving it for now like I said before...The truck has 184,400 miles on it, I'm not really looking to put too much money into it so I'm not really what to do at this point :roll:

 

[Milwaukee]

Sound like it been sludge so bad it clogged oil pump's strainer.

We had issues with those on cars from cities.

First thing we do change oil and use cheapest oil and 1 quart of ATF/ cheap oil filter. Drive for on long highway trip for 100-300 miles then change oil again with cheapest oil/filter drive for 1000 miles then change with good synth oil/ motorcraft oil filter.

Can you look at oil cap's filler do you see sludge inside?

 

[DrSpin]

I've got the same thing with my Ex...After a long trip I noticed the same "Dancing Gauge" I figured that it was electrical as there was no engine noise...initially. I heard the clicking and pulled over. Checked the oil, which was low and dark. Just got an oil and filter job done and replaced the oil pressure sensor...no luck...

I'm hearing "check the oil pump strainer" which would need the oil pan removed which I hear would need the engine lifted out. I'm hoping I am hard of hearing as this seems like an incredible design flaw...

I'm not driving it out of fear so I'm taking it in soon and was wondering what I should ask my mechanic to look for first...Thoughts? Thanks in advance for any advice.