Hi. I am new to the forum and need some help. Was driving along today and noticed a clicking in the engine. Sounds like valves knocking. My thought was that I needed to add some oil. Before I could get to Autozone, my Oil light came on and the gauge dropped to zero. Pulled over, killed the engine, checked under Truck for leaks, (none), checked the oil level, was full. Started the engine and the gauge went up to normal, but still hear the valves knocking. Drove a little ways and lost pressure again. Killed the engine, started back up and the gauge went back to normal. This scenario repeats itself over and over. Just changed the oil 2 weeks ago, and the old oil drained normal, no gunk. Have been told by one person could be oil pump screen or oil pump going bad. Another person said if the oil came out clean, should be nothing wrong with the screen. Please, some of you knowledgable guys give me some ideas!! My Truck is a 2000 F150, 4.2L. I use Ford Motor Oil and Filter.

 

I would drop the pan and inspect the pick up screen. If all looks good, suspect the oil pump.

 

Thanks Toyz. All signs point to that. I've bee told that the motor has to be lifted to get the oil pan out. Is that your understanding as well? Have you had to do this?

 

I knew a guy that over filled his oil and got cavitation from the crank shaft. When it was all bubbled up the pumb would just suck up the air bubbles and the pressure would drop like a rock.

However yours does sound like the screen is sucking up something. With the oil pressure down you probably have a or some lifters that aren't pumped up, should go away when you get the pressure back.

 

Sounds like checking the oil pick up is a good Idea....also I get a mechanical oil pressure gauge, so you know what your oil pressure really is & under what conditions...the factory gauge is not a direct pressure gauge, just a sensor that only requires minimal pressure to activate it.

Most likely you have a sludge build up....try Auto Rx....many have with good results....but follow the directions

I'd also double check the oil pick up after the Auto Rx just to be safe. If you do go the route.
search this form for labnerd...he is far more knowledgeable about oil

also check out bobtheoilguy.com

 

Thanks for the input Guys, sounds like all signs point to screen clog. I've heard of the Auto RX, but it seems if there is sludge, I should just go ahead and do it 100% and drop the pan to inspect/clean. I'm getting conflicting input from some friends and my Chilton Manual. The Manual says the pan just comes out after removing bolts. I have a friend who has a shop and and does some mechanical work, and he says the motor and Trans. may have to be raised some. I have not started yet, but it looks like there may be minimal clearance from the Frame back to Transmission Housing. Either of you have first hand knowledge by doing it on a 2000 4.2 (or similar)?

 

Best way to see if the pan will drop out is just get under there and check it out really. Thats what I would reccomend. Been a while since I have been under mine, and never really checked into that option, but there may be a cross member or something along those lines that you have to remove or work around, but it cant be too mind boggling.

Keep us updated, and good to ya!


-MColford

 

Ok, I have an update and more questions. Tried removing the Oil Pan, but couldn't get it out, not near enough room between Tranny and cross-member, not near enough room to get inside to examine/clean the pick-up screen. Bolted the pan back up. Meanwhile I had ordered some Auto RX additive and started running it through as directed. Been driving the Truck more and more and have gradually gotten to where the pressure gauge stays up. Only thing is, after I have been driving awhile and the engine is good and hot, I will come to a stop light and the gauge will drop. It drops and one second later it goes back up. Drops and back up? I noticed when it does that and I put it in neutral or park to kill the engine, the gauge does not drop. put it back in drive, at the light, and it drops? Once I get going again and get the rpm's back up, the gauge stays up! Any ideas???

 

sounds like the pump to me, i might would also change the oil pressure sensor while your under there

 

Dump the oil and add fresh oil with additive and repeat and repeat. If it keeps getting better you may be on the right track. Sounds like your engine has lots of sludge. As it breaks up it could plug something. You may want to take it to a shop and get them to take off the pan and see what they can see.

A guy on the Dodge Magnum car forum had a loss of oil pressure at high rpm. His problem turned out to be a plugged oil pump screen due to a previous owner not changing the oil. He posted pictures of the screen.

It there is a lot of sludge in the upper part of the engine, it may be impeding the drain back of oil to the pan. This may explain why the pressure comes up after it sits for a while.

Way back I bought a 59 Chevy Impala for $100 just to have something to work on. The engine was full of sludge because the second owner had used non-detergent oil in it for a long time. Then he put detergent oil in it and broke up some of the sludge that plugged the drain holes in the heads. When I shut the engine off and pulled the valve covers, oil gushed out. I scraped a bucket of sludge off the heads and from underneath the intake manifold. It had been smoking really bad when I bought it and the smoking stopped after cleaning out the drain holes because the oil level in the valve covers had been above the valve seals and oil was running down the valve stems into the combustion chambers.

 

You can drop the oil pan by removing the middle of the cross member (it is bolted in) and remove the sway bar and with a little wiggling the pan comes our fairly easy. That's what we did with my2006 expedition.

 

Kathy, this thread is 12 years old. There's quite a difference between your Expy and a 2000 F150 with a V6, especially if yours is a 4wd and his is a 2wd.