No oil pressure at start up, 2001 Tahoe

[OR VietVet]

Overlooking the condescending tone in your post, my general answer is "because that is how they designed it". Additionally, I've periodically had my oil analyzed by Blackstone and historically all wear indicators were in line and of no cause for concern. Bottom line is, everything has been working well so I've been doing what the owner's manual calls for. If this most recent sample shows an increase in bearing wear, I'll happily change to a different oil if it'll counter the degradation inside my motor.

Stick with whatever works for you.

 

[clandr1]

Just changed the oil with Mobil 1 5w-30 high mileage and an AC delco filter. No change. I grabbed a sample and will send it off to Blackstone Labs for analysis before I do anything else.

I just received my oil analysis via email. It seems like good news. Here is their commentary:

Low oil pressure does usually mean bearing wear. Lead is the main indicator of how the bearings are doing, and lead looks alright compared to what we were seeing back in 2019. The other wear metals look fine too, given the interval, so there's no clear sign of what caused the oil pressure to drop. The viscosity is in the appropriate range for 5W/30 and no contamination such as fuel or coolant was found. Low insolubles means oil filtration is working properly. Try about 7,000 miles next time, but let us know if the low oil pressure continues.

I'm wondering if my oil pressure sensor is just going bad and/or getting gummed up (it is original). It seems I have three options in front of me:
1. keep driving it as is, and monitor the oil pressure for any further drop.
2. next time I come up on an oil change interval, run some seafoam in my crank case, hoping it will dislodge whatever sludge might be blocking my oil pressure sensor.
3. change the oil pressure sensor and see if it makes a difference.

Thoughts or suggestions from anyone?

 

[Tonyrodz]

I just received my oil analysis via email. It seems like good news. Here is their commentary:

Low oil pressure does usually mean bearing wear. Lead is the main indicator of how the bearings are doing, and lead looks alright compared to what we were seeing back in 2019. The other wear metals look fine too, given the interval, so there's no clear sign of what caused the oil pressure to drop. The viscosity is in the appropriate range for 5W/30 and no contamination such as fuel or coolant was found. Low insolubles means oil filtration is working properly. Try about 7,000 miles next time, but let us know if the low oil pressure continues.

I'm wondering if my oil pressure sensor is just going bad and/or getting gummed up (it is original). It seems I have three options in front of me:
1. keep driving it as is, and monitor the oil pressure for any further drop.
2. next time I come up on an oil change interval, run some seafoam in my crank case, hoping it will dislodge whatever sludge might be blocking my oil pressure sensor.
3. change the oil pressure sensor and see if it makes a difference.

Thoughts or suggestions from anyone?

In the long run it'll be cheaper to swap out to a new oil pressure sensor. That'll rule out any engine--oil pressure--issues early enough to take preventive action if needed. Just my opinion.

 

[Sam Harris]

I just received my oil analysis via email. It seems like good news. Here is their commentary:

Low oil pressure does usually mean bearing wear. Lead is the main indicator of how the bearings are doing, and lead looks alright compared to what we were seeing back in 2019. The other wear metals look fine too, given the interval, so there's no clear sign of what caused the oil pressure to drop. The viscosity is in the appropriate range for 5W/30 and no contamination such as fuel or coolant was found. Low insolubles means oil filtration is working properly. Try about 7,000 miles next time, but let us know if the low oil pressure continues.

I'm wondering if my oil pressure sensor is just going bad and/or getting gummed up (it is original). It seems I have three options in front of me:
1. keep driving it as is, and monitor the oil pressure for any further drop.
2. next time I come up on an oil change interval, run some seafoam in my crank case, hoping it will dislodge whatever sludge might be blocking my oil pressure sensor.
3. change the oil pressure sensor and see if it makes a difference.

Thoughts or suggestions from anyone?

I vote options 2 & 3. (2, then 3..)

Be sure to replace the sensor with a genuine Delco part too. I broke the first replacement, so had to use the crap brand at Oreillys and it not only gave up 3 months later, it actually sprung a leak, causing a real low oil pressure issue..!

 

[clandr1]

In the long run it'll be cheaper to swap out to a new oil pressure sensor. That'll rule out any engine--oil pressure--issues early enough to take preventive action if needed. Just my opinion.

I vote options 2 & 3. (2, then 3..)

Be sure to replace the sensor with a genuine Delco part too. I broke the first replacement, so had to use the crap brand at Oreillys and it not only gave up 3 months later, it actually sprung a leak, causing a real low oil pressure issue..!

Thanks fellas. After some research last night, I ordered an AC Delco oil pressure sensor (GM 12677836), a Lisle 13250 Oil Pressure Switch Socket, and a Lisle 39400 Angled Disconnect Tool Set. I understand it's easier to do the job without removing the intake if you can disconnect the fuel line, remove the PCV hoses, and have the right u joint and extension for the socket. I'll try to tackle it a week from tomorrow and report back.

 

[clandr1]

Well, this happened today. I guess we can firmly call this a sensor failure.

 

[Tonyrodz]

Well, this happened today. I guess we can firmly call this a sensor failure.



View attachment 279342 View attachment 279343

I'd say so.

 

[Fless]

Well, this happened today. I guess we can firmly call this a sensor failure.



View attachment 279342

I just reinstalled a cluster that I had redone (new steppers) for my neighbor, and the exact same thing happened. We can tell it has oil pressure by the lack of noise, so it has to be the sensor or the circuit.

 

[Sam Harris]

Well, this happened today. I guess we can firmly call this a sensor failure.



View attachment 279342

I went through 4, before it finally decided to keep working. [emoji35][emoji107]

 

[clandr1]

I just reinstalled a cluster that I had redone (new steppers) for my neighbor, and the exact same thing happened. We can tell it has oil pressure by the lack of noise, so it has to be the sensor or the circuit.

Strange, my cluster was just rebuilt in December by a guy who has a TON of experience and positive feedback - maybe just a coincidence? My gauges were working fine before the rebuild, and were working fine after until this recent drop in indicated oil pressure.

I went through 4, before it finally decided to keep working. [emoji35][emoji107]

Oh jeez, were all 4 AC Delco sensors? Hopefully that's not what's ahead of me...

 

[Sam Harris]

Strange, my cluster was just rebuilt in December by a guy who has a TON of experience and positive feedback - maybe just a coincidence? My gauges were working fine before the rebuild, and were working fine after until this recent drop in indicated oil pressure.



Oh jeez, were all 4 AC Delco sensors? Hopefully that's not what's ahead of me...

All but one, yes.

 

[BG1988]

I just received my oil analysis via email. It seems like good news. Here is their commentary:

Low oil pressure does usually mean bearing wear. Lead is the main indicator of how the bearings are doing, and lead looks alright compared to what we were seeing back in 2019. The other wear metals look fine too, given the interval, so there's no clear sign of what caused the oil pressure to drop. The viscosity is in the appropriate range for 5W/30 and no contamination such as fuel or coolant was found. Low insolubles means oil filtration is working properly. Try about 7,000 miles next time, but let us know if the low oil pressure continues.

I'm wondering if my oil pressure sensor is just going bad and/or getting gummed up (it is original). It seems I have three options in front of me:
1. keep driving it as is, and monitor the oil pressure for any further drop.
2. next time I come up on an oil change interval, run some seafoam in my crank case, hoping it will dislodge whatever sludge might be blocking my oil pressure sensor.
3. change the oil pressure sensor and see if it makes a difference.

Thoughts or suggestions from anyone?

that is the problem going by when GM tells you to change the oil... that is where the first mistake lies


4500 miles should be the max OCI those little black specks in the oil is carbon and carbon is very hard it will sand blast away metal, eat seals and damage oil hoses....

 

[Fless]

Strange, my cluster was just rebuilt in December by a guy who has a TON of experience and positive feedback - maybe just a coincidence? My gauges were working fine before the rebuild, and were working fine after until this recent drop in indicated oil pressure.



Oh jeez, were all 4 AC Delco sensors? Hopefully that's not what's ahead of me...

Since two or three of the gauges didn't work properly before I worked on the cluster I think my issue was that they didn't pay attention to any of them. When I pulled it -- no power to it -- the fuel gauge was at 6 o'clock, the temp gauge was at about 11 o'clock. None of the old stepper motors had solid feeling detents as they were rotated.

You could pull the cluster and power it up on the bench to see if that particular stepper motor comes off of the bottom end and jumps slightly to the neutral position (closer to 0) when it's powered up.

 

[clandr1]

Had some time tonight so I installed my oil pressure sensor. The gauge works again, but is still reading between 20-30 PSI at idle after being driven for ~20 minutes.

What oil weight should I run to increase the oil pressure? I guess I'm done with 5W-30...

 

[Sam Harris]

Had some time tonight so I installed my oil pressure sensor. The gauge works again, but is still reading between 20-30 PSI at idle after being driven for ~20 minutes.

What oil weight should I run to increase the oil pressure? I guess I'm done with 5W-30...

Shit. That’s no good. I think you need to test with an external pressure sensor, to confirm.

 

[JonnyTahoe]

Thanks fellas. After some research last night, I ordered an AC Delco oil pressure sensor (GM 12677836), a Lisle 13250 Oil Pressure Switch Socket, and a Lisle 39400 Angled Disconnect Tool Set. I understand it's easier to do the job without removing the intake if you can disconnect the fuel line, remove the PCV hoses, and have the right u joint and extension for the socket. I'll try to tackle it a week from tomorrow and report back.

Hope I got the correct sensor P/N 12616646 ACDelco D1846A

 

[clandr1]

Hope I got the correct sensor P/N 12616646 ACDelco D1846A

When I search a 2000 5.3L GMC Yukon on GM Parts Direct, I come up with GM 19244505.

 

[GBF1]

Factory trans, yes. It was 450k miles or so when the solenoid went out. was the only time I had ever took the pan off as well. Figured it was time for a filter change at that time .

Really all this truck has had is 5 hubs, 5 ujoints, 2 fuel pumps, shift solenoid, oil pump oring, 3 tensioners, thermostat, knock sensors, and.............uhh............. head light switch/blinker switch and the throttle position sensor in the gas pedal. Still runs like new to tell the truth. Ive had it since 100k miles. 2nd owner. was a corporate lease vehicle before that.

and a radiator

Amazing!

 

[JonnyTahoe]

I now use Quaker State 10w-40 in the summer months. Menards has 5qt jugs for less than 20 bucks. I noticed a higher oil pressure at idle using 10w-40. 40 psi cold about 35 hot. I use 5w-30 in the winter but it leaks more from my rear main and that's not getting replaced anytime soon. I never have to add oil I just do oil changes.

 

[JonnyTahoe]

Did the O-ring a few days ago only because I had the oil pan off to install a new oil pan gasket which was the original riveted gasket. Should of been done this fall when the weather was in the 60's but that would of made to much sense. The O-Ring was green and flat exactly like Chads. I also replaced the Starter with a brand new one before I put the Oil Pan back on. Had I known the Crank Sensor was behind the starter I would of got a new one of those as well. You can probably drop the starter down some and replace that sensor but it would of been nice to replace it with the starter completely out of the way. I did not complete this job in only a few hours the new starter itself took a hour as I had some problems installing it. Working upside down on a cold floor is not something I look forward to doing and if my oil leak is the main seal plate gasket I will still have the leak.