Oil pressure

[JEEPSTEVENANAIMO]

last night after work, went to start the jeep. no oil pressure. shut it off. turned it on. still no pressure. did this a few times and than it came back to normal.

was fine all evening driving around n such. full of oil.

this morning same thing happened. after a couple of starts its back to normal.

is this just the sending unit (i got a new one today in case) or should i be looking at something else? engine doesnt burn oil, no leaks.

 

[Steel City 06]

Oil pump might be losing its prime. Basically if the oil drains all the way out of it, it has to suck air for quite some time before it begins pumping oil.

Check to make sure your filter is on tight and not leaking. It might not be leaking oil out, but it could be leaking air in, which would cause this issue. If it keeps happening, easiest solution might just be to change the oil pump.

 

[James9100]

Oil pressure issues are almost always the sending unit. Definitely start with that. I got about a year out of a Standard Motor Products, 250km out of a Mopar (Made in Mexico, purchased from RockAuto), currently running a NAPA, so far so good.

 

[JEEPSTEVENANAIMO]

Oil pump might be losing its prime. Basically if the oil drains all the way out of it, it has to suck air for quite some time before it begins pumping oil.

Check to make sure your filter is on tight and not leaking. It might not be leaking oil out, but it could be leaking air in, which would cause this issue. If it keeps happening, easiest solution might just be to change the oil pump.

is the oil pump external or internal?

nm found it online. i posted below with some oil pumps.

 

[JEEPSTEVENANAIMO]

Oil pressure issues are almost always the sending unit. Definitely start with that. I got about a year out of a Standard Motor Products, 250km out of a Mopar (Made in Mexico, purchased from RockAuto), currently running a NAPA, so far so good.

my local parts store only had BWD brand. i hope it works haha. if not ill put it on the hoist and do the oil pump.

just to confirm the sending unit is just aft of my oil filter right? (going to tighten it after work as well)

 

[JEEPSTEVENANAIMO]

if i need an oil pump which of these do yall reccomend?

 

[James9100]

my local parts store only had BWD brand. i hope it works haha. if not ill put it on the hoist and do the oil pump.

just to confirm the sending unit is just aft of my oil filter right? (going to tighten it after work as well)

Yup, just behind the filter. But I’d seriously considered returning the one you got and getting a decent brand.
Cheap sending units are notoriously unreliable and if I were you I’d want to make 100% sure it’s not the sensor, which is a very easy fix, before going to the work of changing the pump.

Edit: Also, I would definitely hook up a manual oil pressure gauge before even ordering a pump. (Again, I’d make sure it’s not the sending unit before even putting on a manual gauge.)

 

[JEEPSTEVENANAIMO]

Yup, just behind the filter. But I’d seriously considered returning the one you got and getting a decent brand.
Cheap sending units are notoriously unreliable and if I were you I’d want to make 100% sure it’s not the sensor, which is a very easy fix, before going to the work of changing the pump.

Edit: Also, I would definitely hook up a manual oil pressure gauge before even ordering a pump. (Again, I’d make sure it’s not the sending unit before even putting on a manual gauge.)

Im pretty good with mechanics, however how would i hook up a manual oil pressure gauge? i assume to the same port but without that electric sending unit?

i can order a new unit from rock auto. ill take your advise and not use this one.

 

[James9100]

if i need an oil pump which of these do yall reccomend?

Melling M81A is a pretty recommendation I believe.

Im pretty good with mechanics, however how would i hook up a manual oil pressure gauge? i assume to the same port but without that electric sending unit?

Yup you bet.
https://www.amazon.com/dp/B0BBGG72JN?tag=wranglerorg-20

 

[JKP]

Yes, the oil pressure test gauge screws into the hole that the sending unit goes in.

 

[JKP]

And you oil pressure "sending unit" is just a switch that lets the PCM know you have over 6 PSI of pressure and the PCM moves the gauge to the center.

Only the TJs with numbers on the oil pressure gauge are actually gauges. The ones with L and H are just idiot lights in disguise.

 

[JEEPSTEVENANAIMO]

And you oil pressure "sending unit" is just a switch that lets the PCM know you have over 6 PSI of pressure and the PCM moves the gauge to the center.

Only the TJs with numbers on the oil pressure gauge are actually gauges. The ones with L and H are just idiot lights in disguise.

mine has numbers .

appreciate all the replys. looks like i have some work to do on saturday.

 

[Steel City 06]

You'll know if you don't have oil because the engine will make a clacking sound until it suddenly gets oil and quiets down. If the pump is losing its prime it could clack for 5-30 seconds or so until it finally starts pushing oil.

If it's just the pressure switch, you won't notice any unusual startup noises.

As for oil pumps, Melling is definitely a good option. Consider the high volume pump if you have an older engine. High volume works really well with 5W-30.

 

[JEEPSTEVENANAIMO]

You'll know if you don't have oil because the engine will make a clacking sound until it suddenly gets oil and quiets down. If the pump is losing its prime it could clack for 5-30 seconds or so until it finally starts pushing oil.

If it's just the pressure switch, you won't notice any unusual startup noises.

As for oil pumps, Melling is definitely a good option. Consider the high volume pump if you have an older engine. High volume works really well with 5W-30.

i have a bad lifter so it clacks until it gets to one bar of heat than it goes away. but i always have had oil pressure even with that noise. otherwise it just sounds lik ea normal 4.0 (a tractor lol)

 

[macleanflood]

I put a Melling normal volume and pressure oil pump on my 97 on one of my RMS laps.

Big difference between the dash gauge saying no pressure and an actual gauge. I put a T into my sender port and added a GlowShift temperature and pressure gauge. I went through three oil pressure senders until I found one that works...and make sure you have lots of slack on the wire harness.

-Mac

 

[Feralkid]

Do we really need to make modifications to know exactly what the oil pressure is? I would just replace the sending unit and save the time and money.

Here's a couple links to the Mopar switch and a socket to change it.

https://www.amazon.com/gp/product/B0049EEX4W/?tag=wranglerorg-20

https://www.amazon.com/dp/B0002SR2RY?tag=wranglerorg-20

 

[JEEPSTEVENANAIMO]

I put a Melling normal volume and pressure oil pump on my 97 on one of my RMS laps.

Big difference between the dash gauge saying no pressure and an actual gauge. I put a T into my sender port and added a GlowShift temperature and pressure gauge. I went through three oil pressure senders until I found one that works...and make sure you have lots of slack on the wire harness.

-Mac

i htink i may do the T thing as well. seems to be a beter option than a dummy gauge.

 

[JEEPSTEVENANAIMO]

Do we really need to make modifications to know exactly what the oil pressure is? I would just replace the sending unit and save the time and money.

Here's a couple links to the Mopar switch and a socket to change it.

https://www.amazon.com/gp/product/B0049EEX4W/?tag=wranglerorg-20

https://www.amazon.com/dp/B0002SR2RY?tag=wranglerorg-20

with the age of my engine and its miles id like to know whats going on. if it actually loses pressure, its done by the time that light comes on. at least a full mechanical gauge would give me accurate info.

 

[JEEPSTEVENANAIMO]

I put a Melling normal volume and pressure oil pump on my 97 on one of my RMS laps.

Big difference between the dash gauge saying no pressure and an actual gauge. I put a T into my sender port and added a GlowShift temperature and pressure gauge. I went through three oil pressure senders until I found one that works...and make sure you have lots of slack on the wire harness.

-Mac

https://www.amazon.ca/Pressure-Adapters-Stainless-Fitting-M12X1-5/dp/B09HCTDZSQ/?tag=tjforum-20

https://www.amazon.ca/Equus-8244-Oil-Pressure-Gauge/dp/B000EVWEMW/?tag=tjforum-20

https://www.amazon.ca/Mechanical-Pressure-Installation-Fitting-Durable/dp/B0CRHTS7JK/?tag=tjforum-20

will this work? im not positive on the size.

 

[Head Lice]

Do we really need to make modifications to know exactly what the oil pressure is? I would just replace the sending unit and save the time and money.

Here's a couple links to the Mopar switch and a socket to change it.

https://www.amazon.com/gp/product/B0049EEX4W/?tag=wranglerorg-20

https://www.amazon.com/dp/B0002SR2RY?tag=wranglerorg-20

As posted before . . . Duncan Dodge/Jeep wanted $225.- +tax for the sensor with a two week waiting time. Bumper to Bumper in Ladysmith had the part for $45.- tax included. Standard PS404.