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Hi All, my truck has recently presented a new issue.  The oil pressure reads rather high, mostly all the time on the gauge on the dash.

 

I'm thinking the oil pressure sensor could be failing, but I would rather make sure my oil pressure is correct.

 

The bad news is I'm about 200 miles away from home for the next week and don't have my service manual with me (doh!).

 

The good news is I have access to tools so I may be able to solve this while I'm here.

 

I have a mechanical oil pressure gauge and was thinking about testing the pressure first before making assumptions, does anyone know if anyone posted an article about how to properly run the mechanical oil pressure test on my 2001 5.9?

 

Also if it is the sensor does anyone have any thoughts on the best replacement part to get with?  Are there any good lower price aftermarket units or...?

 

Thanks in advance for the help.

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Posted (edited)

In a nutshell...

 

MINIMUM SPECS

At idle minimum pressure is at least 10 PSI.

At 2,000 RPM pressure is at least 30 PSI.

 

Pretty simple to test with a mechanical gauge. Most likely you'll see about 30 PSI at idle and about 60 PSI on the roll. 

 

Welcome back @leety

 

Edited by Mopar1973Man
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Well long time no here from you. I suppose that means the truck has been running hot, straight and normal. 

 

There is port on the of the filter bracket that you can connect a gauge to. Just remove the plug and hook it up. Thatbwil work idleing, if you want to drive it and check you will uave to run a hose of some sort

 

I think most any of the box stores will have what you in a sensor. BWD or Standard Motor products is usually what they have. I have a little of both on mine and so far so good. I am sure Cummins has them too. As far as who's is better I dont know.

 

 

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It's been a busy year so far.  The truck has taken me to see all kinds of wildflowers hither and yon this year.  Amazing CA super-blooming going on everywhere.

 

Thanks so much for all the helpful info.

 

I'll check the pressure and if it's normal I guess it's safe to assume it's the sensor.  I think if the relay is the issue that the pressure would read high with the key on and the engine off, at least that's my understanding.

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If the sensor is way out of wack then there will be error code for it. If it fails within specs then there is no error codes but the information is invalid so that where the gauge test will prove that. 

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6 minutes ago, Ed ke6bnl said:

this is the sensor I put in my 98.5       $16 prime and worked fine I paid over $100 for the previous one.

https://www.amazon.com/gp/product/B01A0RH8O8/ref=ppx_od_dt_b_asin_title_s00?ie=UTF8&psc=1

Thanks for the part info.  Love those Baja's you have there.  I know the guy who invented those, very cool chap.  One day I'll get one of those for over-landing, for now, I have a 914 with a 2.0 type 2 motor to fool around with.

1 minute ago, Mopar1973Man said:

If the sensor is way out of wack then there will be error code for it. If it fails within specs then there is no error codes but the information is invalid so that where the gauge test will prove that. 

Thanks that's great to know.

Does anyone happen to know the torque spec on the plug on the top of the filter?

26 minutes ago, Mopar1973Man said:

In a nutshell...

 

MINIMUM SPECS

At idle minimum pressure is at least 10 PSI.

At 2,000 RPM pressure is at least 30 PSI.

 

Pretty simple to test with a mechanical gauge. Most likely you'll see about 30 PSI at idle and about 60 PSI on the roll. 

 

Welcome back @leety

 

Is there a maximum pressure?

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8 minutes ago, leety said:

Thanks for the part info.  Love those Baja's you have there.  I know the guy who invented those, very cool chap.  One day I'll get one of those for over-landing, for now, I have a 914 with a 2.0 type 2 motor to fool around with.

Thanks that's great to know.

Does anyone happen to know the torque spec on the plug on the top of the filter?

The first time my oil pr. dropped to 0 psi I panicked and when I go home in a rare So. Calif. snow storm I put a pressure gauge  on the oil system and it was good, the next time it acted up I just bought a new pressure switch.

Just got back from a 500 mile trip with the buggies 350 miles of dirt through the Mojave Trail, 150 miles on the freeway from Barstow to Laughlin Nevada. Was nice and not like other years when it is well over 100 degrees most of the time

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1 minute ago, Ed ke6bnl said:

The first time my oil pr. dropped to 0 psi I panicked and when I go home in a rare So. Calif. snow storm I put a pressure gauge  on the oil system and it was good, the next time it acted up I just bought a new pressure switch.

Just got back from a 500 mile trip with the buggies 350 miles of dirt through the Mojave Trail, 150 miles on the freeway from Barstow to Laughlin Nevada. Was nice and not like other years when it is well over 100 degrees most of the time

Sounds like a fun trip. I'm out in Owen's valley this week.  I'm basking in the sun while watching the snow falling on the Eastern Sierras.  I feel like I'm cheating on the weather somehow.  It's kind surreal.

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19 minutes ago, leety said:

Is there a maximum pressure?

 

Not that I know of. I know in the cold of winter that pump can get up in pressure. But the overflow valve on the oil cooler will open and return oil to the pan.

Correction its 15 PSI at idle and 45 PSI at 2k. I was looking for other specs like torque on the plug and max but this is the only thing I found in the FSM.

 

image.png

 


 

Yup.. I was thinking 12V when I spit out the first specs. But it does list an opening spec for the overflow valve. 

 

DONT USE THESE SPECS for minimum pressures.

image.png

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You might ought to look at your sensor harness and be sure it is a 3 wire sensor. The 02's have a one wire switch. Just not sure whether Dodge made the change on the late 01's or the early 02's. Mine is an early 02 and has the one wire switch.

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Now that I've measured the oil pressure mechanically and have a high reading I need to figure out what could cause that.  It appears as the dash gauge may be correct.

 

I built and installed that crankcase ventilation diversion solution posted on this site a while back.  Not sure if that would cause a high-pressure situation if it's clogged.  I'll have to find some air and see if I can blow that out.

 

Any other ideas are welcome on what to look for in a high oil pressure condition.

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The overflow valve is stuck closed. The cap on the oil filter housing has the spring and valve.

 

image.png

REMOVAL
(1) Disconnect the battery negative cables.
(2) Remove the threaded plug, spring and plunger (Fig. 152). Insert a finger or a seal pick to lift the plunger from the bore.
NOTE: If the plunger is stuck in the bore, it will be necessary to remove the filter head.

 

CLEANING
(1) Clean the regulator spring and plunger with a suitable solvent and blow dry with compressed air. If the plunger bore requires cleaning, it is necessary to remove the oil filter head to avoid getting debris into the engine.

 

INSPECTION
Inspect the plunger and plunger bore for cracks and excessive wear. Polished surfaces are acceptable. Verify that the plunger moves freely in the bore. Check the spring for height and load limitations (Fig. 153). Replace the spring if out of limits shown in the figure.

 

INSTALLATION
(1) Install the plunger, spring, and plug as shown in (Fig. 152). Tighten the plug to 80 N·m (60 ft. lbs.) torque.
(2) Connect the battery negative cables.
(3) Start the engine and verify that it has oil pressure.

 

image.png

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1
14 minutes ago, Mopar1973Man said:

The overflow valve is stuck closed. The cap on the oil filter housing has the spring and valve.

 

image.png

REMOVAL
(1) Disconnect the battery negative cables.
(2) Remove the threaded plug, spring and plunger (Fig. 152). Insert a finger or a seal pick to lift the plunger from the bore.
NOTE: If the plunger is stuck in the bore, it will be necessary to remove the filter head.

 

CLEANING
(1) Clean the regulator spring and plunger with a suitable solvent and blow dry with compressed air. If the plunger bore requires cleaning, it is necessary to remove the oil filter head to avoid getting debris into the engine.

 

INSPECTION
Inspect the plunger and plunger bore for cracks and excessive wear. Polished surfaces are acceptable. Verify that the plunger moves freely in the bore. Check the spring for height and load limitations (Fig. 153). Replace the spring if out of limits shown in the figure.

 

INSTALLATION
(1) Install the plunger, spring, and plug as shown in (Fig. 152). Tighten the plug to 80 N·m (60 ft. lbs.) torque.
(2) Connect the battery negative cables.
(3) Start the engine and verify that it has oil pressure.

 

image.png

Sounds like this could be my cause.  I'll get on that tomorrow.  Is that the same plug where I just tested the oil pressure?  It's a bit unclear in the picture.

22 minutes ago, Mopar1973Man said:

The overflow valve is stuck closed. The cap on the oil filter housing has the spring and valve.

 

image.png

REMOVAL
(1) Disconnect the battery negative cables.
(2) Remove the threaded plug, spring and plunger (Fig. 152). Insert a finger or a seal pick to lift the plunger from the bore.
NOTE: If the plunger is stuck in the bore, it will be necessary to remove the filter head.

 

CLEANING
(1) Clean the regulator spring and plunger with a suitable solvent and blow dry with compressed air. If the plunger bore requires cleaning, it is necessary to remove the oil filter head to avoid getting debris into the engine.

 

INSPECTION
Inspect the plunger and plunger bore for cracks and excessive wear. Polished surfaces are acceptable. Verify that the plunger moves freely in the bore. Check the spring for height and load limitations (Fig. 153). Replace the spring if out of limits shown in the figure.

 

INSTALLATION
(1) Install the plunger, spring, and plug as shown in (Fig. 152). Tighten the plug to 80 N·m (60 ft. lbs.) torque.
(2) Connect the battery negative cables.
(3) Start the engine and verify that it has oil pressure.

 

image.png

Okay I see which one it is now.  Perfect thanks, I'll get into that tomorrow.

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Posted (edited)
23 hours ago, Mopar1973Man said:

The overflow valve is stuck closed. The cap on the oil filter housing has the spring and valve.

 

image.png

REMOVAL
(1) Disconnect the battery negative cables.
(2) Remove the threaded plug, spring and plunger (Fig. 152). Insert a finger or a seal pick to lift the plunger from the bore.
NOTE: If the plunger is stuck in the bore, it will be necessary to remove the filter head.

 

CLEANING
(1) Clean the regulator spring and plunger with a suitable solvent and blow dry with compressed air. If the plunger bore requires cleaning, it is necessary to remove the oil filter head to avoid getting debris into the engine.

 

INSPECTION
Inspect the plunger and plunger bore for cracks and excessive wear. Polished surfaces are acceptable. Verify that the plunger moves freely in the bore. Check the spring for height and load limitations (Fig. 153). Replace the spring if out of limits shown in the figure.

 

INSTALLATION
(1) Install the plunger, spring, and plug as shown in (Fig. 152). Tighten the plug to 80 N·m (60 ft. lbs.) torque.
(2) Connect the battery negative cables.
(3) Start the engine and verify that it has oil pressure.

 

image.png

Took this baby apart and everything looks okay in there.  I don't have a way to measure the spring tension but I can't imagine it would have suddenly changed.

 

Any other ideas as to why the pressure is running high?  As the RPMs increase, the pressure goes to the top white line on the gauge and as I compared the dash gauge to the mechanical it seems to be about right.

Edited by leety

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Posted (edited)

What is high? At what oil temp?

 

Where are the sensors located?

 

Based on my experience with a mechanical oil psi gauge the pressure regulator only comes into play with cold oil. 

 

@Mopar1973Man where are those specs you posted from? They don’t match anything I’ve seen for ISB oil pressures. 

 

Everything I’ve ever seen is similar to the numbers you originally posted. 10 at idle, and 30 at rated rpm. That's looking at several different ISB and QSB Cummins manuals. 

Edited by AH64ID
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29 minutes ago, AH64ID said:

What is high? At what oil temp?

 

Where are the sensors located?

 

Based on my experience with a mechanical oil psi gauge the pressure regulator only comes into play with cold oil. 

 

@Mopar1973Man where are those specs you posted from? They don’t match anything I’ve seen for ISB oil pressures. 

 

Everything I’ve ever seen is similar to the numbers you originally posted. 10 at idle, and 30 at rated rpm. That's looking at several different ISB and QSB Cummins manuals. 

Pressure was over 70 psi with mechanical gauge, cold engine, @ idol, as rpm’s increase press’s goes up.  

 

I’m thinking that I’m going to change the oil and filter and see if that helps.

 

 

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Posted (edited)
42 minutes ago, Mopar1973Man said:

 

The 10 and 30 are from the 1996 Dodge FSM.

 

The 15 and 45 are from the 2001 Dodge FSM.

 

Interesting. 10/30 is in every Cummins manual I’ve read. 

 

 

 

30 minutes ago, leety said:

Pressure was over 70 psi with mechanical gauge, cold engine, @ idol, as rpm’s increase press’s goes up.  

 

I’m thinking that I’m going to change the oil and filter and see if that helps.

 

 

 

Over 70 cold doesn’t alarm me. I’d see 80+ cold on my 05, and that was in the cam journal that reads a few psi lower than in the filter head.

 

What does it read warm? By warm I mean several miles/minuets longer than the thermostat opening. Probably 10 miles in 30° weather and 3 miles in 75° weather. 

Edited by AH64ID
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9 hours ago, leety said:

I’m thinking that I’m going to change the oil and filter and see if that helps.

I was going to suggest changing a filter, just never know. What filter are you using currently?

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51 minutes ago, Dieselfuture said:

I was going to suggest changing a filter, just never know. What filter are you using currently?

 

IIRC all the sensors are post filter. 

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3 minutes ago, Evan said:

I've seen high pressure so I changed oil and filter. Right back to normal after change.

 

KISS

 

 

That would more than likely be from old, thick oil rather than filter issues as the OE sender is post filter. 

 

 

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