Any help would be greatly appreciated! LOW OIL PRESSURE

[Donnie88]

I have a 2004 Tahoe LT months back I changed the oil pump because I got a low oil pressure warning. I know I should have went with a pressure sensor first but. I went with a high pressure pump and changed the o ring as well while I was at it. Cause I knew it had never been done on the vehicle. So after the pump changed and all It still chimes constantly with the low oil pressure warning. I changed the pressure sensor and nothing changed. I don’t know if the sensor was faulty or not. On the gauge cluster that reads oil pressure it is all over the place. Constants jumping around and the chime is ridiculous. Sometimes it will ding when I stop. Other times it will ding while I’m driving. Can some one point me in the right direction of what to do here. Thanks!

 

[PNWYukon]

Are you sure it is not your cluster? My '05 cluster went **** up really quickly after on gauge was wacky.

Use a mechanical gauge to check the oil pressure to verify that the cluster is not lieing to you.

The pickup tube could have a crack in it. There are a lot of possibilites.

 

[alpha_omega]

x2 on the above post. Cluster, Pickup tube and sensor would be my first thing to check. Your pressure shouldn’t be jumping around like that. You do have the proper oil viscosity and qty correct? Not being an ass, just checking all the bases.
Have you checked the plugs to see if there’s any “blow-by”? Pull the plug nearest the firewall and the one closest to the radiator (driver side). Send us photos if they are anything except clean.

*Below is only needed only if your cluster and the aforementioned checks out.*
-Do you have a catch can? Have you checked all of your hoses and fittings? Usually fittings will show other issues, but it can throw sporadic pressures as well. When was your last oil change (aside from the obvious pan drop - current mileage and miles since the work)-


Let us know what you figure out and shoot us some more details so we can try to help.

 

[Donnie88]

When I replaced the oil pump I went ahead and replaced the pick up tube and the o ring. Recently done and oil change not even 1200 miles ago. I run castrol edge 5w30 synthetic with k&n filter. I know my cluster may be a little weird sometimes cause my heat hand will still be up some even when the vehicle is off. Plugs checked this morning everything in that area looks wonderful. Sometimes the pressure wants to act normal sometimes it’s passed 80 and then it will sit below zero until I press the gas.

 

[Donnie88]

Note the oil pressure warning isn’t there until the truck is fully warmed up

 

[PNWYukon]

Get the cluster rebuilt and get a machanical oil pressure test done.

 

[swathdiver]

Get the cluster rebuilt and get a machanical oil pressure test done.

He could also add two or three quarts and see if its the o-ring again.

 

[Fless]

Wrong o-ring?

 

[ScottyBoy]

I'm having a very similar issue on my truck. I bought an oil pressure test gauge, but come to find out it doesn't fit with any of the included adapters. I need to order an adapter for LS engines in order to test the oil pressure. Then I will know if I need to replace my oil pump or not. Scared to drive it until then, because the factory gauge is only reading about 5psi. I replaced the sensor with a brand new NAPA sensor shows the same reading.

 

[afpj]

What brand oil pressure sensor did you use? Cheap aftermarket typically don't work on our vehicles.

 

[PNWYukon]

Wrong o-ring?

I used the FEL-PRO 72401 on my 2005. For the past 6 years I always had 40psi on the gauge. Now it is slightly higher. The O-ring I took off was flattened out around the circumference.

 

[ScottyBoy]

What brand oil pressure sensor did you use? Cheap aftermarket typically don't work on our vehicles.

I used the "Echlin" sensor from NAPA. https://www.napaonline.com/en/p/ECHOP6761
It wasn't exactly cheap, it was actually MORE expensive than the OEM AC Delco sensor. But nobody locally had one in stock and I didn't want to wait on shipping, hence how I ended up going to NAPA.

 

[SnowBuck]

2005 XL had low oil pressure (22 at idle, 35 highway). Dropped the pan (a pain as you need to lower the front diff) and used a spatula to clean out the SLUDGE. The screen was like 80% blocked too. O-ring was fine but replaced it anyway. IT'S FIXED NOW: 38 at idle, 42-50 highway. That was all it took!

 

[S1W99]

I have a 2004 Tahoe LT months back I changed the oil pump because I got a low oil pressure warning. I know I should have went with a pressure sensor first but. I went with a high pressure pump and changed the o ring as well while I was at it. Cause I knew it had never been done on the vehicle. So after the pump changed and all It still chimes constantly with the low oil pressure warning. I changed the pressure sensor and nothing changed. I don’t know if the sensor was faulty or not. On the gauge cluster that reads oil pressure it is all over the place. Constants jumping around and the chime is ridiculous. Sometimes it will ding when I stop. Other times it will ding while I’m driving. Can some one point me in the right direction of what to do here. Thanks!

I had the saved problem when an '07. I put transmission fluid in there oil. Ran 20 miles then changed oil. Been 6 months now with excellent oil pressure.

 

[MT Elk Hunter]

I've had a similar situation and it turned out to be the premium oil filter, I can't remember the brand, was too small in volume and restrictive which caused erratic readings. Changing to an OEM or standard oil filter would be and easy and inexpensive test. Now I use WIX or Napa Gold on my street, hunt, and strip vehicles.

 

[Steve Wolfe]

There is a small filter beneath the sender. It is recommended that you replace it when changing the sensor. It can clog and cause bad pressure readings. Not that hard to replace.

 

[Fless]

There is a small filter beneath the sender. It is recommended that you replace it when changing the sensor. It can clog and cause bad pressure readings. Not that hard to replace.

No screen on an NBS engine. Screens weren't installed until AFM came about.

 

[RogerK]

I have a 2004 Tahoe LT months back I changed the oil pump because I got a low oil pressure warning. I know I should have went with a pressure sensor first but. I went with a high pressure pump and changed the o ring as well while I was at it. Cause I knew it had never been done on the vehicle. So after the pump changed and all It still chimes constantly with the low oil pressure warning. I changed the pressure sensor and nothing changed. I don’t know if the sensor was faulty or not. On the gauge cluster that reads oil pressure it is all over the place. Constants jumping around and the chime is ridiculous. Sometimes it will ding when I stop. Other times it will ding while I’m driving. Can some one point me in the right direction of what to do here. Thanks!

Clean you ground strap connections, two on engine block, one underneath driver seat on the frame, cleared my erratic gauge action immediately.

 

[okfoz]

You should be able to check the cluster with a Tech 2. I had one car go wonky, ended up being the gages... Another time it was literally the O2 sensor at the back of the intake.

 

[jwth]

did you clean the filter screen under the oil pressure sensor?