Oil Pressure Gauge Going Crazy

[oidium45]

Hello,
My oil pressure gauge started acting strange the other day. When I have been driving for 20 minutes or so and the engine is hot the oil pressure gauge starts jumping from high to low vary fast. It only does it at idle or below 1000rpm. It does appear to be effected by turning the air conditioning on and off or revving the engine but only slightly. Also load seems to be an issue. When the car is in drive it is much worse than when it is in neutral or park. I have posted a video on youtube.

Best I can figure is either a grounding issue or sensor issue. But I am stumped.

Quick video
http://www.youtube.com/watch?v=lippZk4O4e0

Detailed (rev engine, turn AC on/Off, etc..)
http://www.youtube.com/watch?v=e1DHLLZN9Es

 

[rickybobby]

check your grounds, esecially the engine to frame and frame to body conections

 

[blueka]

The oil pressure sender is actually only a switch and denotes whether there is pressure or not. Have you recently done an oil change? I had this issue after doing an oil change but it corrected itself shortly after. It's a PITA to change the switch on the SOHC engine.


Si

 

[ragajungle]

The sensor is about $10. I'd start there and put a new oil filter on it -

 

[ponch68]

Had a similar issue with my 97 that was easily corrected with a new sensor.

 

[Oxygen]

wow that sucks but damn i got a good laugh from hearing it clicking off of the needle stoppers hahaha ... man that gauge is going nuts!!!

 

[SoNic67]

I had the same problem due to low oil pressure. After 20 minutes, the pressure is dropping so low that would trigger the switch. The sender it is just a contact - good/bad. When the pressure drops below 5 PSI shows zero. In my case I had osscilating low pressure, enough to make that needle jump good/zero.
Eventually it hit that hard the stopper that, when I turned off the ingintion key, it jumped arround, BELOW the stopper. After that it would want to go "up" the short way, but the stopper was in the way. I had to remove the dashboard and rotate it with my finger back to the "above" stopper position.

Putting the car in N or P is increasing the RPM's and that's why the oil pressure is a little better - so the needle doesnt't move that much. Starting the AC drops the RPM's and lowers the oil pressure.

If you change the sensor and it does the same... you are in the same situation like me - low oil pressure. Sorry, after watching the video, I even would bet that is the low oil pressure. If you hear increasing noise in the engine when it does that (like lifters noise at idle), it's clear that is not the sensor.
To change it you need access by removing the driver side wheel engine plastic panel.

I even added a T (1/4" tube from hardware store) and a mechanical pressure gauge to monitor the real pressure.

My story: http://www.explorerforum.com/forums/showthread.php?t=293239

 

[oidium45]

Well, I changed the oil pressure switch, replaced the battery terminals, and the ground from the battery to the frame. I still have the same fluctuations... Guess I will be testing oil pressure next.

 

[SoNic67]

I bet you are hearing the clikety-clakety lifers noise too...
I switched the oil pump for no result and now I am running with 5W40 Mobil 1 oil. It's better but not as it should be.
My "construction" included:

And a plug for if and when I remove one of the sensors (I am not taking the 'T' out anymore):

PS: All pipe fittings from Lowe's plumbing - there are not listed as "auto grade" but I cannot see why not use them. Used pink teflon tape on the threads because is high temperature rated. I was worry that would isolate the electrical grounding of the dummy switch, but it didn't - I bet in some place metal cut the tape because of the torque and made contact on block metal.

 

[oidium45]

Thanks! Yes the litters have gotten much noisier since this started. I just changed my oil and am running synthetic so I am going to try an additive and see if it helps for now. Otherwise I will change to a thicker oil and see what happens.
From what I have read online the most likely culprit is engine wear. Since I do t have the money for a crate or rebuild at the moment I just need to find a cheap temporary fix.

I was wondering if anyone knew wether a high flow oil pump might help temporarily???

 

[SoNic67]

I did replace mine and I used the OEM Motorcraft one. I was wondering if a high flow one would helpt but... it is done. And it's a pain to change it - either you take the engine out or drop the front end and still need to lift a little the engine (that means to disconnect the exhaust manifold and THAT is fun too)...
I did try Lucas Additive and I thought it helped just a little, but just for short runs. Now, like I said I have 5W40 TurboDiesel Mobil One in it... It did helped to a some degree, but is still not super-good. I did add some SeaFoam hoping that I have clogged pasages that would clear. Nothing sensational happen till now (drove just a few miles). Still pressure drops after 30 minutes - it just stays above 8-10 PSI.

The thing is that, I think that my story kind of started when I switched to synthetic oil too. I had it with the synthetic oil - three or four changes - all TOP SHELF Castrol and Mobil One. I wonder if this is not part of the problem. This weekend I will throw out again 30$ worth of oil and try regular (un)blended oil. Maybe even Motorcraft 5W-30...

 

[oidium45]

Ok, SoNic67... Here is what I did.

I put a quart of ATF into the oil and let it idle for about 10 minutes. The engine was hot prior to doing this. I then drained the oil and removed the oil filter. I used an air compressor to force air into the oil pump through the section where the oil filter mounts. I did this hoping to force some oil in reverse through the screen on the pump to remove a clog if there was one. It was a long shot and I was told to be cautious not to blow all of the oil out of the pump because it may not begin pumping again easily if completely empty.

I then replaced the oil with 20w-50 conventional and spliced a mechanical oil pressure gauge in along with the factory sensor just as you did. I don't know which of these things did the job but here are my pressure readings.

Engine cold = 20psi idle/40psi at 2500rpm
Engine worm = 13-15psi idle/40psi at 2500rpm

I am still getting a slight bit of engine noise but it is much better!
FYI, the listed time to remove the oil pan on a 99 ford explorer AWD 5.0L is 16 hours!!! So I am hoping that I will not ever have to do that!

 

[SoNic67]

Yes, oil pan it's a ***** to remove on a 4WD/AWD... I paid my mechanic to do it - it droped the front axle and the realised that it won't clear the pump - it was hitting the steering rack. So he unbolted the exhaust manifold (kinda - he cut some of the bolts with oxy-torch), the motor mounts and lifted the engine a little. That's when I did change the oil pump - for nothing.

I just replaced the diesel oil (mixed with SeaFoam). Back to 5W-30 Motorcraft (synth blend). Now I have 50 PSI at cold idle (better than ever). Worm - 8-10PSI idle/25 PSI at 2500rpm.
You are looking better. I hear the lifters when pressure is below 25-30PSI. My oil was VERY weird looking - thick, cloudy, grey/black... I think I still need to clean it more, I have the feeling that the oil is getting "trapped" up on cylinder head passages and the sump is getting "dry". I just ordered some Auto-RX cleaner...

The air pressure "back feed" is scarry - you could remain with an unprimed oil pump.

 

[ahodges]

Sonic67,

After reading all of your posts about your oil pressure issue I'm beginning to worry about my problem I've talked you about before on a different thread I started. I haven't gotten to checking the oil pressure with a mechanical gauge, but my problem sounds the same as yours except I have the 4.0 OHV, rebuilt.

I've began to describe it to others as a diesel engine sound now too. (clickety clackety). I also don't want to replace my oil pump if that didn't fix your problem. Guess I'll just have to check the oil pressure. I REALLY don't want to pull the engine again!

 

[SoNic67]

See... that was a gamble that I lost. Some 450-500$ worth of (labor, pump, gaskets, oil, filter)... Your milage might vary

 

[Bobberfish]

If the needle on your pressure gauge has jumped the peg to stop it from going all the way down you need to get a really strong magnet and take it around the other way and it will fall right back down against the peg and you'll be good to go start it up and it registers fine or you could just need a new gauge might be the simple fix but I wouldn't go through the oil pump I have a 3 year old reman engine in mine with only about 50,000 miles on it and it came with a new pump and everything so it can't be that it might be the plug on the oil sending unit cuz the engine I had before in there I had overheated severely a couple times and it might have messed that up but anyway try the magnet thing it actually works there's a video on YouTube showing you pretty slick

 

[donalds]

If the needle on your pressure gauge has jumped the peg to stop it from going all the way down you need to get a really strong magnet and take it around the other way and it will fall right back down against the peg and you'll be good to go start it up and it registers fine or you could just need a new gauge might be the simple fix but I wouldn't go through the oil pump I have a 3 year old reman engine in mine with only about 50,000 miles on it and it came with a new pump and everything so it can't be that it might be the plug on the oil sending unit cuz the engine I had before in there I had overheated severely a couple times and it might have messed that up but anyway try the magnet thing it actually works there's a video on YouTube showing you pretty slick

Sorry 12yo thread
The magnet trick does work I have used it

 

[Bobberfish]

I didn't realize the post was 12 years old but anyway my vehicle is 22 years old but the magnet trick is pretty cool my bad on the 12-year-old thing but anyway

 

[donalds]

I didn't realize the post was 12 years old but anyway my vehicle is 22 years old but the magnet trick is pretty cool my bad on the 12-year-old thing but anyway

Don't be offended
I just didn't want you to be waiting for a response from no one

 

[Bobberfish]

Don't be offended
I just didn't want you to be waiting for a response from no one

Thank you so much for your consideration I appreciate it thank you a bunch