Oil Gauge Bouncing

[Christifor]

96 Ford Explorer XLT 4.0 w/250k miles.
I was injured at work & haven't really been driving the XLT like usual for the past couple months. It's been around 20-40 degrees lately in my area. I've noticed the last few times I've started it up, I could hear the lifters, which was odd because I've never heard them before. I only run Mobil 1 oil/filter & occasionally Seafoam it. I take really good care of my XLT. I converted almost all the interior/exterior lights to LED the other day & finished with the dash lights. On top of the new lifter noises when I start up, the oil gauge started jumping around like crazy & it threw the "CHECK GAGE" light. Mostly on colder, harder acceleration. Then it would return to normal. I originally thought it was from cleaning the connectors & messing with the instrument panel, but now I'm concerned with the lifter noise. I've owned the truck for several years & never had this kind of issue. I've read up & see that the oil sending unit may be the issue, or maybe the oil pickup (how would I clean that?). But recently digging into the dash & the lifter noise, I'm not so sure. Any ideas?

Also, the oil gauge reads right in the middle, except when it goes crazy. Only started after the LED bulbs change.

 

[Paul Fithian]

Replace the oil pressure sending unit on the engine. Common problem.

 

[koda2000]

If it was just the gauge bouncing around, I'd suspect the oil pressure switch. However, with your mileage and the fact the you reported the lifter noise after letting the vehicle sit, I think you're just seeing the effects of wear on an old engine and oil draining out of the valve lifters over time.

It could just be that your oil pump is worn and that replacing it would solve the immediate problem, but with over 250k, you might just try cranking the engine without letting it start to get some oil circulating (holding your foot to the floor turns off the fuel injectors) then lift you foot to let it start.

Without a real oil pressure gauge, it's impossible to know what your oil pressure is (the OE sender is more of a ON/OFF switch that will register NORMAL on the gauge as long as you have 5 PSI of pressure). If your needle's bouncing and you're hearing lifter noise, odds are you have less than 5 PSI.

What weight oil are you using?

 

[Mounty99]

Replace the oil pressure sending unit on the engine. Common problem.

Yes. A bad oil pressure sender/switch can cause the gauge to flicker.

 

[Christifor]

If it was just the gauge bouncing around, I'd suspect the oil pressure switch. However, with your mileage and the fact the you reported the lifter noise after letting the vehicle sit, I think you're just seeing the effects of wear on an old engine and oil draining out of the valve lifters over time.

It could just be that your oil pump is worn and that replacing it would solve the immediate problem, but with over 250k, you might just try cranking the engine without letting it start to get some oil circulating (holding your foot to the floor turns off the fuel injectors) then lift you foot to let it start.

Without a real oil pressure gauge, it's impossible to know what your oil pressure is (the OE sender is more of a ON/OFF switch that will register NORMAL on the gauge as long as you have 5 PSI of pressure). If your needle's bouncing and you're hearing lifter noise, odds are you have less than 5 PSI.

What weight oil are you using?

Oil draining from the lifters makes sense! Could it possibly be the oil pickup needs a cleaning? Before letting it sit, it has run VERY strong. Have only had to do maintenance really.

So, as I'm cranking it, hold the gas pedal to prime it? That's what you mean by "holding foot to the floor"? I have always liked the idea of a motor being primed before a cold start. So that'll be cool if I can do so.

I have always used 10w-30.

Like I said, never had an issue with the idiot gauge until I pulled the panel. I'll take a look at the sender & check wiring, clean the connector to see if that changes anything. May have to get back into the dash.

 

[koda2000]

Yes. A bad oil pressure sender/switch can cause the gauge to flicker.

Yes, but it wont make the lifters noisy. I have no idea why the CEL came on. That has nothing to do with oil pressure. You'd probably see the "CHECK GAGE" light come on though.

 

[Christifor]

Yes, but it wont make the lifters noisy. I have no idea why the CEL came on. That has nothing to do with oil pressure. You'd probably see the "CHECK GAGE" light come on though.

I meant "GAGE". Sorry, phone autocorrected!
Fixed original post as well.

 

[koda2000]

Oil draining from the lifters makes sense! Could it possibly be the oil pickup needs a cleaning? Before letting it sit, it has run VERY strong. Have only had to do maintenance really.

So, as I'm cranking it, hold the gas pedal to prime it? That's what you mean by "holding foot to the floor"? I have always liked the idea of a motor being primed before a cold start. So that'll be cool if I can do so.

I have always used 10w-30.

Like I said, never had an issue with the idiot gauge until I pulled the panel. I'll take a look at the sender & check wiring, clean the connector to see if that changes anything. May have to get back into the dash.

Yes, you're priming the engine with oil before starting it. I always do this with vehicles that have sat for a while and I do it every time before I start my '01 ST SOHC, to avoid timing chain noise at cold start. Kinda a poor man's pre-oiler. It probably puts some extra wear on the starter, but it's worth it. I crank my engine for about 10 seconds to build oil pressure before the first start of the day. Then maybe 2-3 seconds after it sits for an hour our so.

 

[Christifor]

Yes, you're priming the engine with oil before starting it. I always do this with vehicles that have sat for a while and I do it every time before I start my '01 ST SOHC, to avoid timing chain noise at cold start. Kinda a poor man's pre-oiler. It probably puts some extra wear on the starter, but it's worth it. I crank my engine for about 10 seconds to build oil pressure before the first start of the day. Then maybe 2-3 seconds after it sits for an hour our so.

That's awesome! I never knew. This is something I would've been doing for years if I had known. Thank you!

 

[koda2000]

Yes, the GAGE light will come on any time a gauge is operating outside of it's expected range. For example, oil pressure below 5 PSI with the engine running.

 

[Christifor]

Ready for a laugh??

I was low on oil! I've never been low on oil in the 5 years of owning my XLT. Apparently I have a small leak somewhere. Was around 1.5qts low.