2001 F-150 5.4L V8 - shows low/no oil pressure

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Triton_330

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Ok, so, it's really cold - below freezing - and I recently went to get some groceries for my dorm room at Walmart and noticed my trucks oil pressure gauge fluctuating on low to no oil pressure. For perspective, Walmart is 2 miles from my campus. When I start my truck the gauge shows no oil pressure. It fluctuate between reading normal pressure and no oil pressure until my temp gauge reads above cold, which it will read above cold after about a mile of driving.

My question is, do you think that there might just be a problem with the gauge - I've been told that Ford's oil pressure gauge is not the most accurate, and when it is less than like 5 or 10 psi it just won't read anything - or do you think that there is something wrong with my truck? I have Kendall GT1 semi-syn 5w-30 in it, btw.
 
I would check the oil to see if there is any water/antifreeze contamination, sounds like you could possibly have a blown head gasket. On the other hand, Ford's gauges can really suck, so if there are no signs of contamination and there is no difference in running, its probably just the gauge.
 
No, the check engine light is not on.

Next time I go out to my truck, I'll check for contamination, but I doubt there is. And, there are no signs of any differences in the way it runs. If I hadn't looked at the gauges, I'd not have known any difference. It runs fine; throttle response is normal, no odd sounds, no vibrations... nothing out of the ordinary.
 
Cars don't like cold weather. Cold robs electricity and stiffens mechanical operation because stuff shrinks. In the old days, we were just happy we got the old heap to run. Now you want it to run quietly
laugh.gif
 
Originally Posted By: andyd
Cars don't like cold weather. Cold robs electricity and stiffens mechanical operation because stuff shrinks. In the old days, we were just happy we got the old heap to run. Now you want it to run quietly
laugh.gif



+1, you do seem to be asking for alot
 
Originally Posted By: renegade_987
Originally Posted By: andyd
Cars don't like cold weather. Cold robs electricity and stiffens mechanical operation because stuff shrinks. In the old days, we were just happy we got the old heap to run. Now you want it to run quietly
laugh.gif



+1, you do seem to be asking for alot


I didn't say anything about noise. It isn't running loudly at all, like I said, it sounds normal, and runs like everything is fine.

I was just wondering if I should be concerned about the gauge reading no oil pressure, or if it's just because Ford's oil gauge is a dummy gauge.
 
You would hear terrible knocking sounds if oil pressure was too low.

On cars with a real oil pressure gauge, there is a sender.
On cars with fake gauges, there is a pressure switch.

If one fails, you might have a warning light illuminate or a needle pointing to the danger zone.

If you have a pressure switch, testing is easy. Pull the plug that is connected to the switch, and use a digital voltmeter. If you see anything other than 0V or OL depending on your meter, you have a switch that is on when it should be off. If the switch worked normally, depending on how it was wired, you would either read 5V, 12V, or whatever voltage the alternator is generating.

If it uses a pressure sensor instead of a switch, you would need a chart that tells you what the resistance would be at a certain oil pressure.

Sometimes the problem is really simple, the sensor fails by leaking oil. If that happens, you already know about the problem.

Good thing those switches/sensors usually cost less than $30.
 
Originally Posted By: DragRace
It's your pressure switch at the oil filter adapter.


This. I just had to replace mine this winter for the same reason.
 
This truck has an on/off pressure sensor that acts like an pressure actuated on/off switch connected to a guage instead of a light. It cannot read actual pressure so any fluctuation is coming from either the sender or something in the wiring.
I would bet the sensor is going bad.
 
So, are you saying (artificialist) that I would be able to see a leak if that was, indeed, the problem? Or could it still be the problem even if there was no leak?

I don't plan on being able to check the voltage anytime soon. There is a bad snowstorm occurring in my area right now. Classes were even cancelled for tomorrow because of it. It's pretty much almost white out conditions. And it's supposed to keep snowing tomorrow, too. Not only that, I don't have the tools available to do that. All I really could do is look underneath my truck and check to see if there's a leak. But I'll have to wait until Thursday or Friday to do it, weather dependent.

Brent_G - how did you do it? Is it something I'd need to have a mechanic do, or would I be able to do it myself? And how much did it cost you?
 
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+1 on the pressure switch. Oil pressure increases in a cold engine as bearing tolerances are tighter and cold oil is more viscous. An engine with very low or no oil pressure would have very obvious performance issues and noises under the hood.
 
Originally Posted By: CurtisB
+1 on the pressure switch. Oil pressure increases in a cold engine as bearing tolerances are tighter and cold oil is more viscous. An engine with very low or no oil pressure would have very obvious performance issues and noises under the hood.


I know this sounds like a pretty bad question... but if the switch is bad, is it really all that important, or is it something that I could wait to fix at a later time in better weather? And, if it is bad, is it still ok for me to drive my truck until I could fix it?
 
Originally Posted By: CurtisB
Oil pressure increases in a cold engine as bearing tolerances are tighter and cold oil is more viscous. An engine with very low or no oil pressure would have very obvious performance issues and noises under the hood.


I think you mean bearing clearances. The tolerance is the range of the acceptable clearance.
 
Originally Posted By: Triton_330
So, are you saying (artificialist) that I would be able to see a leak if that was, indeed, the problem? Or could it still be the problem even if there was no leak?

I don't plan on being able to check the voltage anytime soon. There is a bad snowstorm occurring in my area right now. Classes were even cancelled for tomorrow because of it. It's pretty much almost white out conditions. And it's supposed to keep snowing tomorrow, too. Not only that, I don't have the tools available to do that. All I really could do is look underneath my truck and check to see if there's a leak. But I'll have to wait until Thursday or Friday to do it, weather dependent.

Brent_G - how did you do it? Is it something I'd need to have a mechanic do, or would I be able to do it myself? And how much did it cost you?


You should be able to do it yourself no problem. It's slightly above and beyond the oil filter and not bad to get at. I think it was like $10 for an motorcoach one.
 
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You need to get it to a shop pretty quick. Its either a bad gauge/sensor or worse no oil pressure. You need to know what the problem is and have it resolved. What if its a bad oil pump and you keep driving and spin a bearing? Its just not worth the risk man.
 
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