I just bought a 2005 F-150 pickup at an online wholesale auction lot. I bought it at a price that if there were some problems, I could afford to put some money back into the truck. I was really excited when I picked it up because it was in better then expected condition & the motor sounded good when I loaded it onto the trailer to get it home. When I got home, I unloaded the truck & checked fluids and everything looked good. Took it for a drive & things were going great until about 10 minutes into it the oil pressure guage went to zero & heard some pretty loud valve train noise in the engine. Shut it off & hauled it back. Any idea what could cause this?? The motor ran great right up to this point. Is it possible there is something wrong with the oiling system?? It has 125,000 miles. My plan for now is to pull the pan & see what things look like.

 

It's rare to have one of those oil pumps fail so I would suspect something blocked the oil pickup tube screen or its so sludged up that the cyl head oil drain backs are plugged not allowing the oil to return to the pan fast enough ( long shot) but possible. I figured when I started reading your thread that the oil sender was probably bad but as soon as you said you heard noise thats a good indication that you really did lose pressure. Did the oil look clean on the dipstick and was it all the way to the full mark? I'm thinking something in the oil pan that was floating around until it got close enough to the pickup screen or enough debris accumulated in the 10 minutes you had it running that it plugged the screen. Remove the oil pan plug and see if any coolant/water runs out first now that the engine has set for awhile. Try barring the engine over by hand to make sure it didn't seize from lack of lubrication. Any warranty with the truck? (no doubt another long shot) Good luck,

 

The timing chain tensioner o ring seals will fail on these trucks causing valve train noise. Mostly seen that above 100K miles. Had one that when it started to make noise, you swore that it was getting ready to throw some rods right out the side. Cut it off and restart, and she purred like a kitten. Pretty common problem on the three valves. Something else to look at.

 

I started the motor several times after towing it back & it sounds fine. I even drove it 1/2 mile & was ok. Didn't want to go any further cause I didn't really feel like walking. Oil still looks like new. Filter also looked new. I guess I could go for another longer spin but I'm worried about doing more damage (And walking.) I found out the pickup was from a Ford dealership & it also looks like PS head had been removed...Not sure how that fits into the equation...I just thought it was weird to lose oil pressure after the motor was hot.

 

Would that cause the engine to lose oil pressure??

 

I think bigbronc is on the money with the tensioners. Personally I wouldn't drive it to much until you find the problem and fix it. There should be a repair history on the vehicle if the dealer made a repair. What makes you think the passenger side head was changed?

 

I don't know if the head was changed but I'm thinking it had been removed because the head and valve cover is perfectly clean compared to the rest of the motor. The valve cover casket also looks new

 

I have 2005 F150 5.4l 3V. Have changed oil, filter, Cam Phasers, Tensioners and truck purrs when started and idling. When driving Oil pressure drops and truck rattles like nobodys business. Stop and restart and everything is fine go about 2 or 3 miles does it again. Hit a bump or stop at a stop sign oil pressure drops and truck rattles. Kill it and restart everything is fine. Also there is no metal in oil pan and oil and filter are good. Only use motorcraft and the synthetic oil. Sludge isn't the problem. Any suggestions?

 

Have you had the oil pan off and the sump pickup tube off? I recieved an engine once that had somewhat the same condition. When I removed the oil pan I found a stock tag (paper 3x5 tag with wire tie) in the oil pan. When the truck was started it ran good until the tag was sucked up to the pickup screen and the oil pressure went down. Also saw another engine with a piece of rag left in the oil pan by the mechanic do the same thing. Another possibility is that the "O" ring that is installed on the oil pump end of the pickup tube is missing or damaged and the pump loses its prime. If the pickup tube retaining bolt that holds the tube to the number 4 main is missing or loose the sump can be pulled down tight to the bottom of the oil pan stopping oil flow then pop back up when suction is reduced giving you intermitten oil pressure. The fact that the engine is making noise when the gauge drops means you are actually losing pressure and its not just a bad sending unit. Are you sure you tighten all the bolts during the repair work you just performed?

 

Dynotech- Thanks for your response. No I haven't had the oil pan off yet.
I will do that this afternoon. I have had the truck for a couple of years so I would be surprised if there would be anything in the oil pan. But I will double
check just to make sure. However I did check for metal shavings and such with a magnet and found nothing so that was a bit of good news. Wondering about the solenoids behind the cam phasers as well. All bolts are tight.

 

This an old thread but read bigbroncs post (#3) above regarding the chain tensioners that may very well be the problem you are having as well.

 

Dyno-Finally got the oil pan off and the pick up tube an yep there was the problem sludge. Got it all cleaned up an the truck ran fine. This morning I decide to run to town and the truck started running rough, I stop by Oreillys and have them put the code reader on and to my dismay 13 codes came up.
300, 302 303 304 340 344 345 349 2196

 

Did you ever get your truck running?

 

yes my 2006 f-150 5.4 v3 does the same thing .,but i change everything .,camphaser's ,cam sensor's,2 vct solenoid's,timing chain tensioner's but on this tensioners i found little mud inside and when i take if out the oil preassure sensor i found and i see alot of mud ,or oil with silver thing. so i put one gauge on the oil sensor for see the psi on my oil pump when is cold at firts start up shows 60 psi after 8 min. when the truck is warn it up .,shows at 0 psi so my sugesstion is bad oil pump. any way the oil preassure switch always is gonna show normal preasure on the gauge so i will replacement this oil pump.and i toll you latter what happen.

 

hey my truck wass doing the same shows like 18 codes but it wass because my timing chain marks i put wrong after i fix that problem only shows something with the cam sensor bank 1 or bank 2 sooo the truck made a noise like diesel engine but know after a replacement all sensor and chain tensioner i found my oil pump on cold start up shows 60 psi and when is warn it up shows 0 psi and when i accelerate the neddle goes crazy 0 psi to 30 psi and start making the diesel noise .check you oil pump preasure.