Folks, I got a heck of an issue and I'm plum out of ideas. I need some help in the worst kind of way. Sorry in advance for the length, but context and details is how you get to solutions, right? LOL
Bearing that in mind, I'll give the TLDR version first: My oil pressure sender has gone out before, I had a really bad overheating incident last year, followed by two minor overheating incidents, I suspect those incidents charred my oil and filled it with gunk, my oil pressure sender appeared to go out again, which I felt good saying it was due to that oil gunk clogging the screen, a month later it did it again, but I hadn't replaced the oil yet, so I did the oil and ANOTHER sender/filter last night, it worked fine, then oil pressure read zero again about an hour ago. I'm at a loss and need to figure out what to check and how to stop this from round 5!
Now the long version
I have an '07 Tahoe LT, 5.3 FFV, 285k on the clock.
End of 2018, my oil pressure gauge dropped to zero and the alarm started going off. There were no indications of low oil pressure other than the needle and alarm. I determined it was the sensor itself, swapped that out, problem went away.
A few months after that in March 2019, my AFM took a dump, and rather than a top-end rebuild, I opted to just swap out a full longblock. That was at 200k. Having recently survived the oil pressure sender, I replaced it again with the new engine, just to be safe (and so I didn't have to get up in that firewall again LOL).
Between then and August 2023, no oil pressure issues of any kind. In August, I was driving down the road fat, dumb, and happy, and a huge wave of "water" covered my entire windshield. The passenger side plastic end of the radiator had blown wide open. I had no clue it was my "water" until about 10 minutes later when the temp rocketed from 210 to past 3/4 over the course of about 30 seconds.
I replaced the radiator and all seemed well. A couple weeks later in the school pick-up line, the temp started climbing for no apparent reason. It was about a gallon low on coolant. I thought maybe I was just dumb and didn't fill it all the way, because I saw no evidence of a leak. When it did it again 2 weeks later, I looked a lot harder. Sure enough, there was a slow drip from the water pump. Probably popped a seal or plug when the radiator blew. So between then and December, I was just topping off the coolant every 4 or 5 days until I could afford a new water pump and have time to install it.
Middle of December, oil pressure dropped to zero. As with 2018's party, there were no indications pressure was actually low other than the needle and alarm. I checked the oil and there were chunks of gunk in it. I assumed it was charring from the couple of overheats. Ran a block tester to make sure the head gaskets were good, and concluded it was most likely the sender screen gunked up.
So I replaced the sender and screen again, and yes, the screen was all crudded up. And yes, the problem went away and I had normal oil pressure for a month.
BUT, my fat old a$$ stretching over the engine with a breaker bar for that job... Yeah... triple hernia (really bad umbilical and just normal bad bilateral inguinal). The ER visit to shove my intestines back into my stomach put a kibosh on the oil change and flush I planned after the pressure sensor.
Doctors ain't big on surgeries during the holidays, so I was put on light duty restrictions and scheduled for surgery last week. My wife picks me up from surgery, and I'll be damned, on the way home the oil pressure dropped to zero. I was thinking: "ok, I did this to myself by not doing the oil change."
About an hour after I climbed out of the anesthesia fog, my wife comes in and tells me there's a puddle of oil under the passenger side. Well it's had a rear main leak for over a year now, so some drips are normal, but puddles and being on the passenger side is not. So I hobbled out to the car and checked the oil. The oil was actually clean-looking, but at some point the spot welds on the dipstick tube apparently popped loose and the tube came out of it's hole in the block, puking oil in the process.
With a new, worse oil leak and a faulty reading from the gauge, I couldn't risk letting it wait for me to recover. So I did something SUPER foolish and called my brothers-in-law to come be my hands last night to replace the sender and screen AGAIN, do an oil change and flush, and replace the dipstick tube.
Ignoring that they somehow managed to break BOTH of the heater core Y-joints at the firewall clean off and then proceeded to break two spark plug wires and one spark plug getting the exhaust manifold lose, neither one of them felt like getting a triple hernia, so one of them brought my 16yo nephew to do the oil sender.
Despite confirming he had disconnected the harness, it turns out he dropped the socket over the sender with it still connected. It came out OK, but the socket severed the harness. Thank God I got the kit with the harness! LOL.
After getting the sender out, he went about trying to pull the screen out. After an hour and a half I'm like: "Dude, it's a PITA, but it ain't THAT hard". One of the tools he used was a long jeweler's driver to try and get it out. He claimed it just fell all the way in, like there was no filter there. So I found a "measuring" piece that was small enough to enter the top of the filter, but too big to get through the mesh opening at the bottom. It dropped all the way in too.
Having done it myself on one of the three previous swaps, we assumed he got it out and didn't realize it, threw the new filter and sender in, soldered on the new pigtail and went about fixing the rest of the crap they broke.
At 2am when we finally finished that mess, I drove it home and it was all good. Purred like a kitten and oil pressure was PERFECT.
About an hour ago, I cannot make this up, oil pressure dropped to zero AGAIN.
It now has a fourth brand new filter and sender, brand new oil, brand new filter, and had a chemical flush run on it before the oil change, and STILL it's acting up.
I'm at a loss now. There's still no indication the pressure is actually low, but even with not being able to inspect the old screen last night, I just have a hard time accepting it's clogged AGAIN.
What can I look at here? What can I check? This has to end! LOL!
Bearing that in mind, I'll give the TLDR version first: My oil pressure sender has gone out before, I had a really bad overheating incident last year, followed by two minor overheating incidents, I suspect those incidents charred my oil and filled it with gunk, my oil pressure sender appeared to go out again, which I felt good saying it was due to that oil gunk clogging the screen, a month later it did it again, but I hadn't replaced the oil yet, so I did the oil and ANOTHER sender/filter last night, it worked fine, then oil pressure read zero again about an hour ago. I'm at a loss and need to figure out what to check and how to stop this from round 5!
Now the long version
I have an '07 Tahoe LT, 5.3 FFV, 285k on the clock.
End of 2018, my oil pressure gauge dropped to zero and the alarm started going off. There were no indications of low oil pressure other than the needle and alarm. I determined it was the sensor itself, swapped that out, problem went away.
A few months after that in March 2019, my AFM took a dump, and rather than a top-end rebuild, I opted to just swap out a full longblock. That was at 200k. Having recently survived the oil pressure sender, I replaced it again with the new engine, just to be safe (and so I didn't have to get up in that firewall again LOL).
Between then and August 2023, no oil pressure issues of any kind. In August, I was driving down the road fat, dumb, and happy, and a huge wave of "water" covered my entire windshield. The passenger side plastic end of the radiator had blown wide open. I had no clue it was my "water" until about 10 minutes later when the temp rocketed from 210 to past 3/4 over the course of about 30 seconds.
I replaced the radiator and all seemed well. A couple weeks later in the school pick-up line, the temp started climbing for no apparent reason. It was about a gallon low on coolant. I thought maybe I was just dumb and didn't fill it all the way, because I saw no evidence of a leak. When it did it again 2 weeks later, I looked a lot harder. Sure enough, there was a slow drip from the water pump. Probably popped a seal or plug when the radiator blew. So between then and December, I was just topping off the coolant every 4 or 5 days until I could afford a new water pump and have time to install it.
Middle of December, oil pressure dropped to zero. As with 2018's party, there were no indications pressure was actually low other than the needle and alarm. I checked the oil and there were chunks of gunk in it. I assumed it was charring from the couple of overheats. Ran a block tester to make sure the head gaskets were good, and concluded it was most likely the sender screen gunked up.
So I replaced the sender and screen again, and yes, the screen was all crudded up. And yes, the problem went away and I had normal oil pressure for a month.
BUT, my fat old a$$ stretching over the engine with a breaker bar for that job... Yeah... triple hernia (really bad umbilical and just normal bad bilateral inguinal). The ER visit to shove my intestines back into my stomach put a kibosh on the oil change and flush I planned after the pressure sensor.
Doctors ain't big on surgeries during the holidays, so I was put on light duty restrictions and scheduled for surgery last week. My wife picks me up from surgery, and I'll be damned, on the way home the oil pressure dropped to zero. I was thinking: "ok, I did this to myself by not doing the oil change."
About an hour after I climbed out of the anesthesia fog, my wife comes in and tells me there's a puddle of oil under the passenger side. Well it's had a rear main leak for over a year now, so some drips are normal, but puddles and being on the passenger side is not. So I hobbled out to the car and checked the oil. The oil was actually clean-looking, but at some point the spot welds on the dipstick tube apparently popped loose and the tube came out of it's hole in the block, puking oil in the process.
With a new, worse oil leak and a faulty reading from the gauge, I couldn't risk letting it wait for me to recover. So I did something SUPER foolish and called my brothers-in-law to come be my hands last night to replace the sender and screen AGAIN, do an oil change and flush, and replace the dipstick tube.
Ignoring that they somehow managed to break BOTH of the heater core Y-joints at the firewall clean off and then proceeded to break two spark plug wires and one spark plug getting the exhaust manifold lose, neither one of them felt like getting a triple hernia, so one of them brought my 16yo nephew to do the oil sender.
Despite confirming he had disconnected the harness, it turns out he dropped the socket over the sender with it still connected. It came out OK, but the socket severed the harness. Thank God I got the kit with the harness! LOL.
After getting the sender out, he went about trying to pull the screen out. After an hour and a half I'm like: "Dude, it's a PITA, but it ain't THAT hard". One of the tools he used was a long jeweler's driver to try and get it out. He claimed it just fell all the way in, like there was no filter there. So I found a "measuring" piece that was small enough to enter the top of the filter, but too big to get through the mesh opening at the bottom. It dropped all the way in too.
Having done it myself on one of the three previous swaps, we assumed he got it out and didn't realize it, threw the new filter and sender in, soldered on the new pigtail and went about fixing the rest of the crap they broke.
At 2am when we finally finished that mess, I drove it home and it was all good. Purred like a kitten and oil pressure was PERFECT.
About an hour ago, I cannot make this up, oil pressure dropped to zero AGAIN.
It now has a fourth brand new filter and sender, brand new oil, brand new filter, and had a chemical flush run on it before the oil change, and STILL it's acting up.
I'm at a loss now. There's still no indication the pressure is actually low, but even with not being able to inspect the old screen last night, I just have a hard time accepting it's clogged AGAIN.
What can I look at here? What can I check? This has to end! LOL!
