Another oil pressure sensor? No Pressure Again.

[cntryislandboy]

My wifes Yukon just dropped oil pressure again. Got the turn off engine now warning. Replaced the pressure switch less than year ago, made it about a two weeks and it failed and when to zero pressure again. Replaced it and it's been going well until today.

Checked the oil, pretty sure it was little low. Added about a quart and half. I noticed the oil on the dipstick smelled almost burned if that makes sense. Smelled little better after I added the oil. Started it up and pressure went up to about to just over 20, ran for about five minutes all seemed well. Went to gas station about a mile away a couple hours later and on the way home got the ole turn off engine warning no pressure.

My wife also stated the check engine light didn't come on this morning but it did just come on, on my way back from the gas station. Code reads P0521 which is oil pressure sensor issue basically.

Any suggestions at this point. Should I just replace the sensor again, essentially for the third time in a year. Or could there be a bigger issue I'm not seeing.

Thanks.

 

[Foggy]

Did you replace the little plastic filter that is with the oil sender last time ???????

 

[cntryislandboy]

Did you replace the little plastic filter that is with the oil sender last time ???????

I had to have a shop do it because I didn't have the time so I can't be certain. I'll try and find the invoice and find out.

 

[wjburken]

Got a few questions.

How was it determined that the sensors were bad and that you didn’t actually have a pressure issue?

What brand of sensors were put in?

How many miles into an oil & filter change is this happening?

Either you have the worst luck with getting bad oil pressure sensors or something else is going on.

 

[cntryislandboy]

Got a few questions.

How was it determined that the sensors were bad and that you didn’t actually have a pressure issue?

What brand of sensors were put in?

How many miles into an oil & filter change is this happening?

Either you have the worst luck with getting bad oil pressure sensors or something else is going on.

Unfortunately I can't answer some of those. I had a shop replace the sensor the first time and under warranty the second time. I would like to think they confirmed this was the issue before replacing the sensor.

As far as miles into and oil change, it's always been towards the end of the oil change cycle. I think it's about due for another one shortly. After talking to my wife about about, I think it was showing low pressure a couple months ago but ended up getting the oil changed and the issue when away. Could this be solved by getting the oil changed more frequently? I read something about Lucas Oil Heavy Duty Oil Stabilizer helping.

 

[wjburken]

Unfortunately I can't answer some of those. I had a shop replace the sensor the first time and under warranty the second time. I would like to think they confirmed this was the issue before replacing the sensor.

As far as miles into and oil change, it's always been towards the end of the oil change cycle. I think it's about due for another one shortly. After talking to my wife about about, I think it was showing low pressure a couple months ago but ended up getting the oil changed and the issue when away. Could this be solved by getting the oil changed more frequently? I read something about Lucas Oil Heavy Duty Oil Stabilizer helping.

Many places will simply replace the part you ask them to change without actually verifying that that part is the problem.

The fact that the oil pressure comes back up after an oil change leads me to believe it’s probably not a bad sensor.

I had this happen with my 2007 Silverado before I traded it. Got the low oil pressure warning. Checked the oil level and it was fine. Put an analog gauge in the sensor port and it read low. Cleaned the screen and instead of putting the old sensor back in, I put a new OEM sensor in and it read low. Changed the oil and filter and pressure was back to normal.

What brand of filter are you using? How long do you go between oil changes?

 

[cntryislandboy]

Many places will simply replace the part you ask them to change without actually verifying that that part is the problem.

The fact that the oil pressure comes back up after an oil change leads me to believe it’s probably not a bad sensor.

I had this happen with my 2007 Silverado before I traded it. Got the low oil pressure warning. Checked the oil level and it was fine. Put an analog gauge in the sensor port and it read low. Cleaned the screen and instead of putting the old sensor back in, I put a new OEM sensor in and it read low. Changed the oil and filter and pressure was back to normal.

What brand of filter are you using? How long do you go between oil changes?

Right not there is a puralator filter. Usually go by the computer for oil changes. I think I will be changing my own oil from now on. I typically use a FRAM filter, I forget which one, but it's the top of the line along with the red valvoline red max life.

I didn't see any signs of leaking under the good, check all the valve seals and any area I thought could be an issue. No signs of any leaks anywhere.

However down by the oil pan looks pretty oily, and up by the oil filter. Not sure if this is from leaking or what. I get it will have some road grime, but I think it's more than that. I also noticed a couple spots on my drive way that could be oil. We just bought the house so I wasn't comply sure. But Im convinced there is at least a little oil dripping.

I cleaned it all up and will check it when I get home tomorrow and see if I can spot any spots leaking again. I also figure I'll do my own oil change this time. I'd like to drain it myself and see how much comes out. I guess there is the possibility I am leaking and the pressure is genuinely low.

 

[wjburken]

Right not there is a puralator filter. Usually go by the computer for oil changes. I think I will be changing my own oil from now on. I typically use a FRAM filter, I forget which one, but it's the top of the line along with the red valvoline red max life.

I didn't see any signs of leaking under the good, check all the valve seals and any area I thought could be an issue. No signs of any leaks anywhere.

However down by the oil pan looks pretty oily, and up by the oil filter. Not sure if this is from leaking or what. I get it will have some road grime, but I think it's more than that. I also noticed a couple spots on my drive way that could be oil. We just bought the house so I wasn't comply sure. But Im convinced there is at least a little oil dripping.

I cleaned it all up and will check it when I get home tomorrow and see if I can spot any spots leaking again. I also figure I'll do my own oil change this time. I'd like to drain it myself and see how much comes out. I guess there is the possibility I am leaking and the pressure is genuinely low.

I would go with a 3000-5000 mile oil change interval and not go by the oil life monitor on the dash.

As for the leaks/seeps, a couple common areas for oil to leak/seep in that area are the oil pan gasket and the gasket where oil cooling lines attach, or the blocking plate if there are no cooling lines.

 

[BADRIDES]

You might be headed for a new oil pump. The last 2 Tahoes my dealership has worked on with oil pressure sender switch problems ended up needing pumps.

 

[cntryislandboy]

I would go with a 3000-5000 mile oil change interval and not go by the oil life monitor on the dash.

As for the leaks/seeps, a couple common areas for oil to leak/seep in that area are the oil pan gasket and the gasket where oil cooling lines attach, or the blocking plate if there are no cooling lines.

I defiantly think I'll monitor it a little better. It's my wife's ride so I kinda forget about it until she says something.

I did look under there today after cleaning it up yesterday, so it say for almost a full day. I did notice oil coming out from a cover (about the size of coke can diameter) that looks likes it's above the sway bar. The other leaking area appears to be up by the oil filter. Hope I'm about to say makes sense, I'll try to figure out how to add photos. But the flat area above the oil filter has oil that has leaked onto it. There is a bolt that is up there enough you would need an extension to get to is covered in oil. So my guess that bolt or a seal somewhere up there is leaking. Also right next to the oil filter is a bolt that has oil. This area appears to have a seal because it to parts connected. Like I said, hope this makes sense. I'll try to post pics.

 

[cntryislandboy]

You might be headed for a new oil pump. The last 2 Tahoes my dealership has worked on with oil pressure sender switch problems ended up needing pumps.

How did they determined it was the pump. I'd hate to just start throwing parts at it.

 

[cntryislandboy]

Here’s a few pics, hope it helps.

 

[wjburken]

I defiantly think I'll monitor it a little better. It's my wife's ride so I kinda forget about it until she says something.

I did look under there today after cleaning it up yesterday, so it say for almost a full day. I did notice oil coming out from a cover (about the size of coke can diameter) that looks likes it's above the sway bar. The other leaking area appears to be up by the oil filter. Hope I'm about to say makes sense, I'll try to figure out how to add photos. But the flat area above the oil filter has oil that has leaked onto it. There is a bolt that is up there enough you would need an extension to get to is covered in oil. So my guess that bolt or a seal somewhere up there is leaking. Also right next to the oil filter is a bolt that has oil. This area appears to have a seal because it to parts connected. Like I said, hope this makes sense. I'll try to post pics.

Does the cover you are referring to look like what is in the picture? That is an inspection hole so you can look up into the bellhousing and see between the motor and the transmission. You can remove that and see if you have a leak at the rear main seal for the crankshaft coming out of the motor or if the oil is coming from above that.

 

[cntryislandboy]

Does the cover you are referring to look like what is in the picture? That is an inspection hole so you can look up into the bellhousing and see between the motor and the transmission. You can remove that and see if you have a leak at the rear main seal for the crankshaft coming out of the motor or if the oil is coming from above that.
View attachment 365329

Yes that is one of the spots, it was clean yesterday and now you can tell oil is coming out of there.

 

[gooffeyguy]

Yes that is one of the spots, it was clean yesterday and now you can tell oil is coming out of there.

Pop that cover off with a screwdriver and use a flashlight and look, feel inside. That is a low point and oil may not be coming out from it, but just running to it from the outside.

That first Pic looks like it may be the O-ring on the oil cooler block or the gasket for the oil cooler line block.

 

[cntryislandboy]

Pop that cover off with a screwdriver and use a flashlight and look, feel inside. That is a low point and oil may not be coming out from it, but just running to it from the outside.

That first Pic looks like it may be the O-ring on the oil cooler block or the gasket for the oil cooler line

Popped the cover off, looks fairly clean inside. I think your right, I think what tiny bit is in there is run off since it’s a low point. It’s only in the corner and a very time amount. Here’s a little better pic I think. From what I can tell it looks like maybe the leak is coming from the 2 pieces that are bolted together. You can see a portion of the oil filter and to the right of that is where it looks like the leak is, unless it’s higher up and can’t see. But I looked it over pretty good and this seems to be the spot that has the most oil showing.

Does that look like the O Ring your referring to. That seems like a job that might be a bit over my head.

 

[cntryislandboy]

Pop that cover off with a screwdriver and use a flashlight and look, feel inside. That is a low point and oil may not be coming out from it, but just running to it from the outside.

That first Pic looks like it may be the O-ring on the oil cooler block or the gasket for the oil cooler line block.

So I replaced the oil cooler gasket. It still appears to be leaking a little. I’m wondering if I put it on the wrong way. The old one fell before I could see how it was on there and the new one was slightly thicker on one side of the metal core than it was the other.

 

[gooffeyguy]

So I replaced the oil cooler gasket. It still appears to be leaking a little. I’m wondering if I put it on the wrong way. The old one fell before I could see how it was on there and the new one was slightly thicker on one side of the metal core than it was the other.

I don't think it matters which way the gasket goes.

The leak could be from the O-ring that is on the side of that block. There is a post on this forum somewhere about replacing it. Basically, there is a round plug that takes either an Allen or Torx bit to remove and there is an o-ring that seals it. Replace the o-ring with a correct size viton o-ring.

Like I said, I can't remember the details, but there is a post about it with pics

 

[YukonRog]

I'm just throwing this out....I had a couple bad Oil Pressure Senders. One that just leaked. Oil will run down the DS. If you can, lie on top of the motor on the DS and see if you can get your phone on the sender and see if it's dry, or leaking. Sometimes you can get your hand with your phone in where you can't get your head. At least you can then eliminate that.

 

[muncie21]

Responding to the oil leak question (not the pressure sensor) since you replaced the oil cooler gasket, the two remaining suspects are the O-ring that @gooffeyguy mentioned or the pan gasket. Let's hope it's the O-ring as the pan is a PIA, especially if you have AWD.