Another oil pressure sensor? No Pressure Again.

[HughW]

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.

Oil changes are very important with these engines My daughter got a red oil light on her 2013 Tahoe so when I checked oil it was full but very black so I changed oil and filter but decided to tow it to the shop because Of the red oil light warning And oil pressure reading low. They could find no problem with engine and did the pick-up tube test and that was not a problem. She has been driving about 9 thousand miles since then and I insisted on 4000 mike oil changes. No oil warning has occurred So in my opinion , infrequent oil changes was the problem

 

[Efingee]

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.

The coke can sized cover you mentioned is the transmission bell housing inspection cover. If oil is leaking from there then you may very well have a bad rear main seal. (Which is very common) The transmission and flex plate must be removed to replace the seal. If the fluid from the cover is red then the front pump seal of the transmission is leaking which also requires removal of the transmission. If the pump seal is bad then you also have to determine the reason for the failure.

 

[gooffeyguy]

Oil changes are very important with these engines My daughter got a red oil light on her 2013 Tahoe so when I checked oil it was full but very black so I changed oil and filter but decided to tow it to the shop because Of the red oil light warning And oil pressure reading low. They could find no problem with engine and did the pick-up tube test and that was not a problem. She has been driving about 9 thousand miles since then and I insisted on 4000 mike oil changes. No oil warning has occurred So in my opinion , infrequent oil changes was the problem

I've always done 5k mile oil changes, it's a nice, easily remembered number. The oil life monitor is usually around the 30-35% mark.

 

[Geotrash]

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.

Did you use an OEM gasket or a Fel-Pro? The Fel-Pro is a different design than OEM and is harder to get to seal properly. So much so, I stripped out one of the bolts on mine trying to get it to seal and then had to put a Helicoil in it. OEM or Dorman only for that gasket.

 

[HughW]

I've always done 5k mile oil changes, it's a nice, easily remembered number. The oil life monitor is usually around the 30-35% mark.

 

[HughW]

I did 5k or 6k too and didn’t worry about going over because I was using full synthetic oil But when this happened (oil pressure alert with red oil light ) I’m being cautious and changing at 4k. Since the mileage is over 150k. I went to high mileage full synthetic oil too.

 

[okfoz]

I had 2 sensors go out within a few years... I do not know why they go out honestly. Fortunately I have a guy who does the Remove and Replace for $50 + the cost of the part which I brought to him...

 

[cntryislandboy]

Did you use an OEM gasket or a Fel-Pro? The Fel-Pro is a different design than OEM and is harder to get to seal properly. So much so, I stripped out one of the bolts on mine trying to get it to seal and then had to put a Helicoil in it. OEM or Dorman only for that gasket.

I think it was the fuel-pro, it was the only one they had. It looked the same as the one that came out.

I ended up taking it to a local shop because I’m going out of town for work and my wife needs to drive it. They said they put a gauge on it and had pressure matching what the sensor was showing. It started up mid to low 20s then dropped to almost zero after driving s few minutes. They suggested adding a high volume oil pump and replacing the sensor again for $2,400 Or $2,100 for just the pump. They also state this may not fix the problem. The only other is to replace the motor. That the one I have is just wore out. I find this hard to believe, it’s a 2012, and 183k miles. My 04, had 246k when I traded it in. They did say I could continue to drive it and i may get a lot more out of it or I may not.

Needless to say I’m a little frustrated. Thanks again for your help. At least I was able to learn a few things.

 

[Geotrash]

I think it was the fuel-pro, it was the only one they had. It looked the same as the one that came out.

I ended up taking it to a local shop because I’m going out of town for work and my wife needs to drive it. They said they put a gauge on it and had pressure matching what the sensor was showing. It started up mid to low 20s then dropped to almost zero after driving s few minutes. They suggested adding a high volume oil pump and replacing the sensor again for $2,400 Or $2,100 for just the pump. They also state this may not fix the problem. The only other is to replace the motor. That the one I have is just wore out. I find this hard to believe, it’s a 2012, and 183k miles. My 04, had 246k when I traded it in. They did say I could continue to drive it and i may get a lot more out of it or I may not.

Needless to say I’m a little frustrated. Thanks again for your help. At least I was able to learn a few things.

Ouch. $100 says it's either the o-ring on the pickup tube that's sucking air and dropping oil pressure, or the VLOM isn't torqued down adequately, bleeding off pressure at the tops of the towers. Dropping the oil pan to replace the o-ring is a PITA but cheaper than replacing the pump. I highly doubt you need an engine. Properly maintained, these things will go 400K+.

 

[cntryislandboy]

Ouch. $100 says it's either the o-ring on the pickup tube that's sucking air and dropping oil pressure, or the VLOM isn't torqued down adequately, bleeding off pressure at the tops of the towers. Dropping the oil pan to replace the o-ring is a PITA but cheaper than replacing the pump. I highly doubt you need an engine. Properly maintained, these things will go 400K+.

What is the VLOM?

My guess is the shop wouldn't able to tell it's the o-ring unless they dropped the pan? Would running the motor and spraying soapy water all around the oil pan to see if it bubbles be an option. This might sound really dumb, I'm no mechanic, but in my line of work we do this to find leaks sometimes.

I'll probably give that a try. I guess dropping a few more bucks and a few hours won't hurt. At least I'll be learning something. I've got a lot of crap to work on in the garage before I can get the car in there and work on it, at least my wife will be happy. I don' think my neighborhood would appreciate a car on blocks in the drive way for a while. Not to maintain my drive way is sloped.

I guess worse case scenario is I park her for a few months and save for something nice from Texas Speed, LOL. I've always wanted a project car, just didn't imagine it would get it so soon.