2003 4.6 with low oil pressure light coming on

[crobson]

I was driving around a few weeks ago and I hear a "ding" I look at the insturment panel is says low oil pressure and the dummy guage shows no pressue at all. So I pull to the side of the road and get ready to shut it down when the light goes away the message goes away and the dummy guage reads pressure again. So I leave it running, no ticking, or knocking, no unusual noise at all really. The guage continues to say no press. and then show pressure. I figured that I may have a faulty sending unit, I went and got one put it on plugged everything back in and changed oil while I was at it. Started her up hoping the problem would be gone, and of course not! So the next thing I gues would be to hook up a mechanical guage to see what is actually happening. I plan on doing this within the next few days.

I am not sure how the oil pump could go bad, I could be wrong but it dosnt seem to be much too it... I would think as long as the crank is spinning the pump should be pumping. Right?

If anyone has had any issues like this or heard anything like this I would appreceate the information

Thanks Chris

 

[Hitchhikingmike]

as long as the crank is turning the pump is pumping. how may miles are on your engine?

 

[jrford]

the mechanical guage will tell you everything.
rare, but i've heard if you toast the main bearing you can lose oil pressure, over heating, sudden loss of oil. Pump maybe. . .
again

 

[EasyRhino]

Seems you understand that the gage is a 'idiot gage', good. The low OP light and gage match, so that is 'normal'. How many miles and any mods? Been around these engines for years and have never heard of oil pumps failing. Any rhyme or reason to the events leading to the occurence?

Have you done the routine checks first? Oil level first. If the level is good and the sending unit is good, the choices get harder. Did you have a recent oil change (i.e. what has changed recently if anything). If so, do it again, and inspect the old oil filter you replace.

Where I would go next is to buy and, and at least temporarily install, a real oil pressure mechanical gage.

 

[coghij1]

Crazy thing. I actually knew a girl who had an 02 with the 4.6 and hers did this same thing and the oil pressure gage would go back and forth from normal to no pressure. I don't remember anything being seriously wrong with the car though because she drove it for a long time this way until she finally traded it in. Hopefully its not anything major.

 

[Exp03Limited]

Mine did the same thing and turned out to be a simple fix, replaced the oil sending unit.

 

[crobson]

The truck has 116,000 on her, she was running just fine no problems what so ever just started doing it one day. I did notice when changing the sending unit, oil, and filter that the filter was not toataly full of oil like I would think it should be, there was however some oil in the filter. Nothing has realy changed with the truck.

I have not been able to hook the mechanical guage up yet, havent had any time, but will soon. Could it be possible that I got a defective sending unit from autozone? I wouldnt think so, as the symptoms were the same after I changed the unit out.

 

[crobson]

Is there any way that the where the crank goes through the oil pump could be worn causing the pump not to work properly, or is this something that cannot happen or dosnt happen?

Thanks to all you guys for your information!

Chris

 

[rileyrs]

a mechanical unit would be the next step in my opinion.

 

[galbre]

My 2002 4.6 has had this problem for over 50k miles (I"m currently at 103k miles) When it first ocurred I also replaced the sending unit but it didnt fix the problem either. It would bounce periodically from normal to low with the accompanying "check gauge" light. Sometimes it would go days without happening. Lately it has been reading constantly low. My engine hasn't seized yet so I'm ignoring it. A mechanical gauge would be a good backup.

 

[crobson]

So I checked the pressure with a mechanical guage today, I was getting 70 psi on cold idle, which I think is damn good! I gave it a few revs to about 4 grand and the pressure would go to 100 psi. I went and got a 2nd sending unit sice they are only 10 bucks, put it in, no change. It looks like I have some kind of issue with the guages or wiring.

If I were to get a set of guages from the junkyard would I have to get the car retuned to work with the computer, PATS ect...?

Thanks Chris

 

[bs81]

I've got an 03 Mountaineer 4.6l that this exact same thing just started happening on. No engine knocks. I've changed the sending unit, and the oil and filter already, but it didn't fix it. I went and got a mechanical gauge but haven't had a chance to install it yet... Did you ever find out what the cause of the problem is? Did you have to get a new cluster?

Thanks,
Brian

 

[crobson]

The problem with mine was two broken wires inthe harness, sounds like u may have the same issue, soldered mine back together and has been working well ever since. There is a post detailing how to fx the issue.

 

[bs81]

do you have a link to the post? where is the wiring harness located?
thanks

 

[crobson]

Here is the link for the write up on how to fix this issue, hopefully it works. If not just click on 02-05 explorers, then stock 02-05 explorers, and in that section at the top there are a bunch of how-to guides. Click the one that is titled " Have a 4.6L? Here's a problem I bet you all have..." Click there, this is a very detailed writeup and there are also pics, I fould it very helpful.

http://www.explorerforum.com/forums/showthread.php?t=287097

 

[D Hook]

Clicked on the link and read through it but didn't see any reference to the oil pressure sender. Does that harness also contain the wire running to the OP sender?

 

[crobson]

Yes, when I took mine apart there was what looked like 3 power wires, one for the A/C comp., one for the oil press. sending unit and I think the other may be oil level, but not 100%. Anyways two of mine were cut clean through and they were the comp. power wire and the oil pressure sensor power wire. I soldered in new pieces of wire, wraped it with a new piece of wire loom and electrical tape and everything has been working the way it should since.

Oh, also something very special if i remember correctly ford runs power wire for the starter in with that bundle as well, im pretty sure some of the protecive wire coating had been worn away on that as well. I ended up wraping it up a bit as well for extra protection.

 

[scottfab]

Yes, when I took mine apart there was what looked like 3 power wires, one for the A/C comp., one for the oil press. sending unit and I think the other may be oil level, but not 100%. Anyways two of mine were cut clean through and they were the comp. power wire and the oil pressure sensor power wire. I soldered in new pieces of wire, wraped it with a new piece of wire loom and electrical tape and everything has been working the way it should since.

Oh, also something very special if i remember correctly ford runs power wire for the starter in with that bundle as well, im pretty sure some of the protecive wire coating had been worn away on that as well. I ended up wraping it up a bit as well for extra protection.

Sure seems like there should be a safety recall on this issue. I was fortunate enough to have seen mine wearing away at the harness one day when I was under the front. I rerouted it. Then a few years later I read that post (like given in this thread) on it.

 

[gonzo6962001]

This was not very good advice and I learned the hard way because what you didn't mention was the plastic timing chain guides when they come apart they go down in the oil pan if they block the oil off to go to the pump so that's another reason why you can lose oil pressure and come back and lose it and come back and the motor will sound fine until it blows up trust me I know

Seems you understand that the gage is a 'idiot gage', good. The low OP light and gage match, so that is 'normal'. How many miles and any mods? Been around these engines for years and have never heard of oil pumps failing. Any rhyme or reason to the events leading to the occurence?

Have you done the routine checks first? Oil level first. If the level is good and the sending unit is good, the choices get harder. Did you have a recent oil change (i.e. what has changed recently if anything). If so, do it again, and inspect the old oil filter you replace.

Where I would go next is to buy and, and at least temporarily install, a real oil pressure mechanical gage.