Yesterday Mrs. Cusser was towing the horse in her 2014 Yukon Denali 6.2 (under 100K miles) and suddenly check engine light (the "submarine" light to her) came on and the oil pressure gauge went to zero (all other gauges working properly). So she called me, and of course she had trouble opening the hood, and trouble finding the oil dipstick, and trouble trying to check the engine oil level. Without her able to confirm engine oil level, I didn't feel comfortable for her to keep driving. So I had her call AAA and bring to the house, as the independent mechanic we use once a year (but have brought in several new customers) is closed for vacation every Christmas-New Years interval.

I checked the engine oil, was fine. Engine sounded perfectly normal. I couldn't locate my code reader (think it's 100 miles away) and saw some videos of GMs having exact same symptoms, due to bad oil pressure sender. I didn't feel it was worth it to drive a few miles to get the code(s) read either, figured they'd show as sender code. I disconnected the battery leads and touched the two cables together to clear the memory, reinstalled those, and when I turned the key to "Run" position, the oil pressure gauge pegged to full, the dropped down to zero in 30 seconds. When I started the engine, the oil pressure stayed at zero, and after a short while the check engine light again came on.

Knowing that the sending unit is hidden at rear top of engine and a blind R&R, and I'd have to remove stuff to just do this blind because my hands wont fit in, I've decided to just take it to the mechanic 5 miles away on Tuesday. Because I think the issue is only the sender and that the engine does have full oil pressure, I think it's safe to drive there. Any thoughts? Thanks.

Of course, on my other (non-GM) vehicles, R&R of their oil senders is a 5-minute job.....thanks GM !!!

 

Update: weather was nice today (71F with some wind), and I had time, I decided to revisit this myself. I had declined to try this job when we had a 2005 Yukon with a Driver Information Center warning, but its oil pressure gauge still worked fine.

One should know that I watched quite a few YouTube videos before starting, but still had to lay towels over the engine, use a stool, and do some of the work left-handed. I was able to remove one end of a plastic tube at the rear of the engine for more clearance. I did not remove a second tube or the fuel line at its connection. I broke off the gray "protector" on the oil sender harness connector with a screwdriver, and with left hand pushing a long screwdriver against the connector tab and right hand on the connector, I was finally able to release the connector from the oil sender. The special 1 1/16" oil sender socket I bought like 25 years ago did not fit over the sender, I used a 27mm deep socket. Then I used a 1/2" wobble extension, about 5" long, and that was not easy to push into the 27mm deep socket, but the socket had to go on first. Then I used a stubby 1/2" drive flex ratchet to unscrew the oil sender.


Of course once that was unthreaded it fell somewhere so that took 15 minutes or more to find & remove. So I went to O'Reilly and bought PS508 oil sender, which actually did fit my special socket (but I still used the 27mm deep one).

So with the new sender (I did not even try to find if the engine had a filter screen, I didn't feel one) purchased, I tied a piece of twine around it it case I dropped that, and screwed that in a few turns with my left hand. Then I put the 27mm deep socket over that, then the wobble extension, then the stubby flex ratchet. 15 minutes later I had that screwed in, and actually in similar orientation as the factory one. So 10 minutes more to remove those tools without dropping them. So 15 minutes later I was able to blindly turn the connector to correct orientation to snap that on.

I re-connected the one plastic pipe I had removed, and started the Yukon: no oil pressure displayed, and check engine light was still on. So I disconnected the battery, touched cables together to erase all codes/clear computer, reconnected the battery, and started it up: all was working - SUCCESS !!!

So even though The Cuss cannot fix everything, I was successful today. Yes, this took me several hours, but since I'd just ordered Mrs. Cusser 4 new tires (as the 5-year-old ones were quite dry-rotted), felt why not save $300 to $500 by doing this myself. Some mechanics apparently remove the entire intake manifold for easy access, but that's labor hours. For me, trouble with the special oil sender socket I had threw me for a loop, but the 27mm deep socket I had did save me.

Realize that 4 different times I packed up stuff and quit, saying the mechanic could try his luck Tuesday, but The Cuss is a persistent little cuss, for sure. Mrs. Cusser is ecstatic, and promised to take care of me tonight....

 

Great write up. I think when I'm working on something of this degree of difficulty that they should make the engineers that design this stuff, have to work on them before they release them to production. Maybe they wouldn't make it so difficult. 😡

I remember on a 1980 Chevette, that to replace the starter, you almost have to remove the engine. It was relatively easy to detach the starter from the engine, however trying to figure out how to retrieve it from that dark hole between the engine, firewall, and inner fender was the difficult part. It had to be oriented exactly right in order to remove it. 😱

 

Since I had just ordered 4 new tires for the Yukon that morning, I was happy to save several hundred dollars; I saw flat rate time for this online at 3.6 hours, look into free https://charm.li for repair info and flat rate hours.

https://charm.li/GMC%20Truck/2013/Yu...Labor%20Times/

 

That is a fantastic website. Nice find!.

 

I saw one video (today) where someone used nippers to cut away some of the little plastic shield (that apparently does nothing but block access) to make access to the sender significantly easier.

My only "contribution" and tip to ease this R&R for others in the future is I tied a 2-foot twine/string around the new sender so I could retrieve it if I dropped it in the process of getting it to thread in. After threading in, I pulled on the twine to break it.

 

Oil pressure still fine.

Today we took our 2014 Yukon Denali to the shop to get its transmission, transfer case, and front and rear differentials serviced. Without a lift, and the different fluids/pumps required, too much for me. $331 fluids and materials, $255 labor, pretty much what I expected. We bought this 3 years ago with 76K miles and "in writing" that such had been changed just before we bought it, but now at 118K miles (some of that towing a horse), just makes sense to have that done. $641. $331 in parts/materials, $255 labor. Pretty much what I was expecting. This is a local/family ASE mechanic shop - who I tell folks is my go-to mechanic - and have used him for 2 decades, and have sent numerous folks from my workplace to him as they feel if I can trust him, that's good enough. Well, I only use his shop like once every year or two, as most stuff I handle myself.

When we purchased this 2014 Yukon Denali in 2022 with 76K miles, the paperwork from the small non-dealer sales lot stated these fluids had all been changed by them before it was put up for sale. So even if I trusted that seller 100% that such was done because it was "in writing", now it's 3 years and 44K miles later - so I felt it was time.

 

I don't know how to edit or edit the title of this thread, so I'll just add on/continue here.

Today I raised the Yukon front and lubed the outer tie rod ends with my grease gun. Since the tires/wheels are so heavy, and my wheels interfered with getting my grease gun onto the nipple, instead of removing the wheels I purchased a right-angle adapter for $5.50 from O'Reilly, and it worked well.

 

100k service for bride's 2020 Tahoe this week. Oil/filter, rear diff, front diff, transfer case, plugs/wires & clean various sensors. $1,200. Back in the day I would have laughed at someone spending that amount of coin for preventative maintenance. Today it is a necessary expense if you choose to keep your ride for years & high mileage. Also work that I no longer have the time or ambition to do myself. I am thankful to have a competant, trusted mechanic to take care of my wife's car.

 

Seems reasonable these days.

One can expect to pay over $100K for a 2026 Yukon Denali.