1999 Exp XLT 5.4L 2WD Oil Pump Failing?

1999 Exp XLT 5.4L 2WD Oil Pump Failing?

Posted in the Ford Expedition Forum


Nashville, TN

#1 Jul 3, 2008
Hello to All,
I am an IT consulting professional by trade with some modest automotive repair and tooling experience.
I have a 99 Exp XLT 5.4L 2WD unit that has (I think I have narrowed it down) a failing/failed/clogged oil pump (after much observation and forum research).
The truck has 170,000+ miles and started to have the oil pressure guage drop off and warning light coming on and off abruptly when the oil level got below a certain point. I would add a quart of oil or so (back to "full") and the behavior would go away. The engine burns oil but there is no visible tell-tale smoke in the exhaust and no visible leaks under the vehicle where it is parked at night. I had always attributed this to just the "normal" behavior for this engine as it has aged.
Then, recently, the oil guage fell off abruptly and the oil light came on and a VERY perceived knocking in the lifters (I assume) would simultaneously become evident. The engine has long had a slight knock, but, never had a loss of power and I assumed 87 octane and just aging. But this new behavior was abrupt. I added oil and verified the level and that was good. Now, when I start the engine, it starts up normal and idles fine, but, shortly thereafter (with the oil level good), the oil light comes on, the guage falls and the knocking commences. I have not been driving it except gradually up and down the driveway to observe the behavior.
after MUCH reading, and all things considered, it appears that the oil pump could indeed be suspect. what makes me further think this is that there are moments that the oil light will go off and the guage returns to its nominal position and the knocking abruptly stops and again idles fine. It seems to manifest the problem more as I begin to apply the gas and rev the engine up. It will often start to rev up normally and then the light comes on and knocking commences.
So, am I on track with this??? The truck has been parked in the driveway ever since as we have a 3rd car. I am now getting around to trying to get this looked at. But, I assume I will have to have it towed if I take it to a shop. So, I am trying to do some homework.
Is this a costly repair??? What else might it be? If the pump pick up line is clogged and the pump itself it OK, how to test and likewise, is there anything I might do to correct that situation? Is this something I could do myself or will the engine, tranny, whatever, have to be pulled out and apart to even get to where the pump can be examined?? I have read that you have to remove the timing chain and the oil pan to get at it. And, with a 9 year old, 170000+ mile vehicle, is this even worth bothering with fixing or should I "scrap" it (Kelly BB indicates about $1500 for this)?
Any input would be greatly appreciated. I know throwing enough $$$ at it will fix it, but, with gas $ and the economy the way it is, I simply need to be smarter about spending $ in general these days.
Thanks very much!!

United States

#2 Oct 24, 2008
I'm having the exact same problem. 198,000 miles. Did you figure it out?

Anderson, SC

#3 Oct 30, 2008
Hi, I have a 2001 EB Expedition. It has the 5.4 Triton with 161,000 miles. It burns oil but not alot. Also my oil gauge will drop to 0 and the light will come on. But the problem here is the oil pressure gauge sensor, this sensor i think cost around $30. This could be part of you're problem with the light but the knocking is another issue. And with the engine, these have 2 cams and basically 2 timing chains that are very hard and expensive work on.

United States

#4 Nov 3, 2008
my 2001 eb expedition did the same thing about a year ago, the oil pump probably isn't bad because its a gearrotor oil pump; it's either good or bad. I dropped the oil pan and the pick-up tube was stopped-up from mixing regular oil and synthetic-- I was told that the 2 together will gum up, and it did! try that before you tear your whole engine down because the crank has to come out to get the pump out.

Madera, CA

#5 Feb 7, 2009
My 02 EB Expedition has been doing basically the same thing yall are describing here. Oil pressure gauge will drop and oil light comes on. Then suddenly everything will go back to normal. We have changed the oil now and have also replaced the oil pressure sending unit. After everything was completed, warmed up the truck for about 10 minutes and went to pull out of driveway, when it happened all over again. Oil gauge dropped and light came on. Then everything went back to normal for a few seconds. Most everyone we have talked to, said if it was the oil pump, the pressure would stay down and not jump up & down like its doing. So now after reading previous posts, I'm wondering if it could be the oil pump pick-up tube being clogged. I'm assuming this would be alot less hectic to check and correct, than needlessly attempting to change the oil pump. If anyone has any input, please feel free to do so. I'm not very mechanically inclined, so I'm welcome for any sound advice.

Franklin, TN

#6 Aug 5, 2009
Sorry to hop back on this thread after a year! I posted to as number of places and forgot this one. I actually found it again searching on this again.:-) Glad to see some replies!! basically, i have let the Exp stay parked this past year. Had another car "loaned" to us (it was my late mother's and my dad just said we could drive it as long as needed). So, I decided once again to look at it.

Wildwilly, I think you may be right in that it is clogged. I seafoamed the crankcase again, and it improved a little, but, I had not thought to drop the oil pan. What is involved with this???

Franklin, TN

#7 Aug 5, 2009
Let me add that in going back to some earlier links I had saved, I rediscovered that with 4x2 Expeditions (what I have) the engine has to be lifted up a few inches to make clearance between the bottom of the oil pan and the top of the transmission to even get the pan off!:-( This is not something I am equipped for. As the truck is now 10yrs old with that mileage, I don't want to throw a lot of money at it. So, is there a chemical treament (soak, whatever) that might disolve out sludge blockage of the strainer or pickup tube. I have Seafoam'ed it but only with 1/2 can added. I have heard of filling with ATF and/or Auto-RX and letting it soak for a period of time (not running the engine at all of course!) might be effective.

And, is there some way to determine if the strainer or pickup line is clogged up WITHOUT pull off the oil pan?? There is knocking at cold start and it dies away. I had read that this can also be a sign of clogging restraining oil flow to the lifters and what not after it has been sitting for a while.

I am not looking for a miracle cleanout/cure here; just want to squeeze one or two more years out of it. As long as the oil pressure shows up normal, the engine appears to idle AND run (under a load) as it always has.


Austin, TX

#8 Jan 29, 2010
i have '97 expedition that recently locked up on me. while coming back from a trip my old pressure guage started to act funny, going up and down erratically while i was on i-h 35 going 70 mph. i drove it a bit longer until my pressure guage went down and stayed down. i got off the interstate and turned into a side street. when i got to the stop, my truck turned off,and that was it. no knocking just tuned off and wont start. i got undeneath ande tried to turn the engine by hand but no dice. a friend of mine toldmeto try turning with cheater bar and replacing oil pump. what are my real options???

Farmington, MI

#9 Feb 5, 2010
my 97 did the same thing. the motor was locked so i bought a new motor, its used but now im fighting the oil press thing, it is fine then it will randomly drop off like none other. its clankn now and i need to fix it.

Raleigh, NC

#10 Feb 22, 2010
I have a 2004 Expedition that I let sit in my driveway for 13 months before I finally was able to come up with the 4800 dollars needed to buy a new (used) engine as was told by mechanic that was needed. The shop told me i had burned out my engine, although I was religiously changing my oil every 4 to 5000 miles. I then took it to a old ford mechanic who has his own shop. He pulled the oil pan and knew the trouble right away as there were plastic pieces in the oil pan that cracked from the oil pump. It was the timing belt cover tensioner, which has a plastic cover that goes around the oil pump. Once the tensioner loses tension, the plastic cracks and the oil pump no longer works. The complete part was 680.00 and installation cost around 1000, so for less then half of a new (used) engine, my Expy is now back on the road. He did work from the front of the engine taking out everything working back to fix the timing belt cover tensioner.
mr moore

United States

#11 Nov 23, 2015
Hello 1999 f250 LIGHT duty 5.4 triton 343,689 miles or "half heavy my oil gauge drops only when warmed up but only at a stop, knocks I check the pick up tube my crossmember is welded in so I had to take the motor mounts out lift the engine with a jack on the harmonic balancer very carefully so I can get the oil pan to squeeze out tube was clogged with a plastic piece no clue how it got there but it's out now codes were pulled for a oil sender "switch" bank 2 and egr valve tested by ford for free ha. Seaford is not corrosive as chemtool or marvel mystery oil fyi I've tighten the journals for the cams it helped quiet replaced valve cover gaskets switched to high mileage Fram filter 10 40 ( I live in Texas needs thick) it has shavings in the oil every oil change for damn near three years anyways the oil pressure it's fine when it's warming up but what it's warm when ever I'm stopped it drops it might go back and forth on the gauge but mostly it stays down one I give it gas just a tad it is fine runs like a charm but it drops it becomes a little rougher I think the wires on the sender are nicked or stripped back a little far that's all I got

Fort Worth, TX

#12 Oct 14, 2016
i have a 99 ford expedition for some reason truck is burning oil up with in a matter of a month of getting a oil change. no oil leaks and no sings of coming out the back pipe. what could be the problem ?

thanks ;
young woman who knows nothing about cars.

Kissimmee, FL

#13 Feb 26, 2017
I have a 1999 ford expedition and my oil gauge keeps going up and down.when it goes all the way down it makes a weird noice.

Anybody knows why it does that...

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