Low oil pressure but truck oil level is within ok range on dipstick

[RedRamRollin]

I change my oil every 3000 miles and my filter and I run full synthetic Castrol edge high mileage and I probably have done 10 to 12 oil changes this year which is kind of Overkill now my engine has been doing fine all year I have a 2005 Dodge ram 1500 4.7 l Magnum I was driving today and all the sudden on the interstate my oil pressure dropped completely to low all at once. I'm only two thousand miles into my oil change and I checked my oil level this morning cuz I check it once a week and my coolant level both were normal my oil pressure dropped completely too low at bottom of the gauge then the truck shut off and died so I pulled over there was no knocking no pinging no weird engine sounds and when I check the fluid level in the oil with the dipstick it was normal and within range same as it was this morning but upon trying to restart the truck it doesn't turn over and the oil pressure remains reading low and it has a check engine light but no codes also I noticed when I put it to axillary and listen for the hum of the fuel pump it isn't humming so I'm trying to figure out what that would be cuz I have oil in the engine and it ran fine this morning and I had no problems with it and I change my oil a lot any advice would be appreciated also I've noticed recently that in my oil fill cap on the bottom of the cap it looks like snot like I yellowy ***** mixture. I only have 142xxx on my truck and it runs strong everyday for 1.5 hrs of daily highway 55mph commute. Any info would be greatly appreciated. I also got under the vehicle with a flashlight and there is no noticeable external leaks on the engine no drips underneath the truck and like I said the oil level is within ok range on the dipstick. Did the computer ECM fail shut the truck off or does the sensor in the block tell the computer there's an issue when there isn't will shut the truck off or is the issue something internal. Any help is greatly appreciated.

 

[Arth]

I change my oil every 3000 miles and my filter and I run full synthetic Castrol edge high mileage and I probably have done 10 to 12 oil changes this year which is kind of Overkill now my engine has been doing fine all year I have a 2005 Dodge ram 1500 4.7 l Magnum I was driving today and all the sudden on the interstate my oil pressure dropped completely to low all at once. I'm only two thousand miles into my oil change and I checked my oil level this morning cuz I check it once a week and my coolant level both were normal my oil pressure dropped completely too low at bottom of the gauge then the truck shut off and died so I pulled over there was no knocking no pinging no weird engine sounds and when I check the fluid level in the oil with the dipstick it was normal and within range same as it was this morning but upon trying to restart the truck it doesn't turn over and the oil pressure remains reading low and it has a check engine light but no codes also I noticed when I put it to axillary and listen for the hum of the fuel pump it isn't humming so I'm trying to figure out what that would be cuz I have oil in the engine and it ran fine this morning and I had no problems with it and I change my oil a lot any advice would be appreciated also I've noticed recently that in my oil fill cap on the bottom of the cap it looks like snot like I yellowy ***** mixture. I only have 142xxx on my truck and it runs strong everyday for 1.5 hrs of daily highway 55mph commute. Any info would be greatly appreciated. I also got under the vehicle with a flashlight and there is no noticeable external leaks on the engine no drips underneath the truck and like I said the oil level is within ok range on the dipstick. Did the computer ECM fail shut the truck off or does the sensor in the block tell the computer there's an issue when there isn't will shut the truck off or is the issue something internal. Any help is greatly appreciated.

Wow this is hard to read. Please try to space this out a little.

Not totally sure on why your truck isn't turning over but I always start with the basics. Check battery connections and alternator connections. If those are good check your battery voltage and have it checked. Easy cheap things to do.

As far as the low oil pressure I'm not too sure.

 

[gofishn]

Old days, yellow snot on underside of oil cap meant coolan in oil. nowadays with tighter engines just means some moisture not crack head. key is to check the dipstick if it shows yellow scummy oil, you got issues.

either way, get it to a mechanic you trust and who knows what the heck they are doing for a diagnosis.

 

[JohnnyMac]

Hi,
Sorry to hear of your issues. When you say it "doesn't turn over", do you mean it cranks but doesn't start or does it start then stop or it actually does not crank at all?

As far as the loss of oil pressure, it could be a few things, but since it's not making knocking or ticking noises I would bet it's the oil sending unit/sensor (possibly the gauge) that's tricking the ecm into shutting itself down to prevent catastrophic engine damage which is why it won't start/run.

Maybe disconnect the battery for a bit to clear the fault then try again. See if it will run for a bit before it shuts itself down on low oil pressure. I would think if your oil pump was clogged or failed, you would have heard some engine noise.

Good luck and please keep us posted.

 

[Ghostman]

I agree mostly likely the "oil pressure sensor" or its wiring. But that's not to disregard anything else.
Get the codes pulled
Has it been able to start yet, or still not starting?
Always invest in your own code reader, they are pretty cheap now days.
(Assuming you don't have code reader) find someone who has a code reader, or if truck is running/driveable get to an auto parts store, they will read and give you the codes, free. Always have your Chilton/Haynes manual as well. All your code are listed in there.

There is a way you can pull your codes without a code reader, I don't remember the specific process at the moment, you should be able to google it, or one of us can get back to you with that process.

But first thing is getting the codes.

 

[Ghostman]

Here is one way you can use to try and check your codes without code reader:

(Without starting the truck) Turn the key on and off 3 times, do not engage starter. On the third cycle, leave the key on. It will flash with any codes (if there are any) and it just reads 'DONE' if have no codes.

Have pen and paper to write them down.

May not work for everyone, but it's worth a try for you.

 

[Ghostman]

To obtain C-codes perform a Gauge Cluster Check: hold trip and turn key to run. Gauge lights will turn on to verify function, sweep gauges will move through sequence to very function, codes will display in ODO.

INSTRUMENT CLUSTER FAILURE MESSAGE
Fault Code Description
01 Airbag warning indicator output circuit shorted.
02 Airbag warning indicator output circuit open.
03 ABS indicator output circuit shorted. .
04 ABS indicator output circuit open.
05 MIL indicator output circuit shorted.
06 MIL indicator output circuit open.
07 Wait to start indicator circuit shorted.
08 Wait to start indicator circuit open.
0B BTSI output circuit shorted or open.
22 Headlamp switch input circuit shorted.
23 Headlamp switch input circuit open.
24 Turn hazard switch input circuit shorted.
25 Turn hazard switch input circuit open.
27 Courtesy/dome output circuit shorted or open.
28 Glovebox/map lamp output circuit shorted or open.
29 Cargo lamp output circuit shorted or open.
40 Wiper switch input circuit shorted.
41 Wiper switch input circuit open.
42 Wash/beam input circuit shorted.
60 Passenger door lock switch input circuit shorted.
61 Passenger door lock switch input circuit open.
62 Passenger door lock switch input circuit stuck.
63 Driver door lock switch input circuit short.
65 Driver door lock switch input circuit stuck.
66 All door lock output circuit shorted to ground or voltage.
67 All door unlock output circuit shorted to ground or voltage.
68 Driver door unlock output circuit shorted to ground or voltage.
6C Driver cylinder lock switch input circuit shorted.
6E Driver cylinder lock switch input circuit stuck.
80 Incorrect odometer value found. .
81 Remote radio switch input circuit high.
82 Remote radio switch stuck.
A0 Internal module FLASH memory checksum failure.
A1 Internal module bootloader failure.
A3 Battery voltage open.
A5 TCCM messages not received.
A7 VIN checksum error.
A8 VIN previously stored.
A9 PCI bus internal failure.
AA PCM messages not received.
AB TCM messages not received.
AC ABS messages not received.
AD FCM messages not received.
AE ACM messages not received.
AF SKIM messages not received.
B0 RKE fob batteries low.
B1 RKE module communication link.
00 Done All Diagnostic Trouble Codes (DTC) have been displayed.

This also may be helpful... (For all 3rd Gen owners)

Compliments of @lilfroger
THREAD: https://www.ramforum.com/threads/c-codes.1253/

 

[RedRamRollin]

All my lights were working and I was driving down the interstate when it shut off .It shut off imidiately after oil pressure guage went to low. All my lights and four ways continued to work after truck shut off so I doubt it was the battery. It would crank. It would start but imidiately cut out and shut off again. I heard no engine sounds before it shut off and all electrical components lights etc still work

 

[RedRamRollin]

I tried to read the codes with a scan tool through the obd 2 port but there are no codes to show

 

[Jason G Slabaugh]

Its the oil sending unit. Cheap fix. Mine did that on my 5.7l. Just went to zero but oil was full. Put a 10 dollar sensor in it. Fixed

 

[RedRamRollin]

I replaced the oil sending unit. Didn't fix the problem. Still reading 0 oil pressure still won't turn over. I put it in the shop. I'll post an update tomorrow after they do the diag.

 

[Ghostman]

I replaced the oil sending unit. Didn't fix the problem. Still reading 0 oil pressure still won't turn over. I put it in the shop. I'll post an update tomorrow after they do the diag.

Wow that is odd, could possibly be a bad electrical wiring short or connection. Glad you got it in somewhere to get checked. Let us know what they come up with.

 

[JoeRam14]

I replaced the oil sending unit. Didn't fix the problem. Still reading 0 oil pressure still won't turn over. I put it in the shop. I'll post an update tomorrow after they do the diag.

Sounded like the sending unit could have been the problem. Interested to see how this turns out.

 

[RedRamRollin]

The diag found that my truck died and lost oil pressure all at once because my fuel pump quit. Which shut the engine off due to no fuel pressure and dropped the oil pressure to 0 on the guage because the engine was no longer running. Also explains the check engine light with no codes. Same as running out of gas. Putting in a new pump this weekend (after I get paid on Friday then I'll post a picture or two and finally see if this fixes it .thank you to all of you.

 

[gofishn]

Glad you found out what caused the issue.
Even more glad you returned and shared it with everyone.
You never know, you could have just saved many people a lot of headache, with this very same issue, down the road.

 

[JoeRam14]

The diag found that my truck died and lost oil pressure all at once because my fuel pump quit. Which shut the engine off due to no fuel pressure and dropped the oil pressure to 0 on the guage because the engine was no longer running. Also explains the check engine light with no codes. Same as running out of gas. Putting in a new pump this weekend (after I get paid on Friday then I'll post a picture or two and finally see if this fixes it .thank you to all of you.

Keep us updated. Hope it works out for you.

 

[RedRamRollin]

I will. Fixing it tomorrow

 

[RedRamRollin]

All fixed. Was the fuel pump. No other issues. Back to running. Just cleared 143k. Thanks for all the help fellow ram owners! Here's some pics of my truck .

 

[RedRamRollin]

Just a few more pictures ..

 

[JohnnyMac]

Glad you got it fixed. Thanks for following up. Nice truck!