C8 oil drain bolt missing gasket
Thread Starter
Intermediate
Joined: Oct 2023
Posts: 47
Likes: 71
C8 oil drain bolt missing gasket
I have my local dealer (Bill Pierre in Seattle) do the 500 mile oil change on my 2024 C8. At 2,500 miles I decided to do an oil change myself. I'm an experienced mechanic and have a full shop with lifts and evey/any tool. When I removed the drain bolt the top/small o-ring was missing. I purchased a new OEM bolt and then completed the oil change a few days later.
Shortly after I went to the dealer and showed them the bolt with the missing o-ring. Presumably they should have noticed the missing o-ring and either replaced it or used a new bolt with the correct o-ring. When questioned, the tech said "oh, some C8's come like that from the factory" Yeah right, that sounds like a bunch of crap.
Two questions come to mind:
1. Anybody know exactly the function of that small 0-ring? Obviously, it's to seal, that's not the question.. The question is more precise.
2. Based upon 1. above, is it likely or possible some damage may have been done?
Thanks in advance.
Shortly after I went to the dealer and showed them the bolt with the missing o-ring. Presumably they should have noticed the missing o-ring and either replaced it or used a new bolt with the correct o-ring. When questioned, the tech said "oh, some C8's come like that from the factory" Yeah right, that sounds like a bunch of crap.
Two questions come to mind:
1. Anybody know exactly the function of that small 0-ring? Obviously, it's to seal, that's not the question.. The question is more precise.
2. Based upon 1. above, is it likely or possible some damage may have been done?
Thanks in advance.
Pro
Joined: Feb 2007
Posts: 697
Likes: 663
From: Portage Michigan
Based on this image, I am making an assumption that the small o-ring on the tip of the drain plug seals the reservoir and it segregates the sump (dry) from the reservoir/pressure circuit. When removing the drain plug the oil in the reservoir flows into the sump and then out to the drain pan.
Thread Starter
Intermediate
Joined: Oct 2023
Posts: 47
Likes: 71
Thank you gents, that's helpful. I'm hoping there's not some tiny o-ring plugging up some oil passageway now.....
Not real happy about this dealer. Things seem to go wrong there a lot. I took my '17 Escalade there for a coolant flush. When it came back it has a radiator leak. Feels like they break stuff just so they have some predictable service work ahead......
Not real happy about this dealer. Things seem to go wrong there a lot. I took my '17 Escalade there for a coolant flush. When it came back it has a radiator leak. Feels like they break stuff just so they have some predictable service work ahead......
Sr.Random input generator
Joined: Jan 2008
Posts: 7,798
Likes: 2,229
From: Sammamish, WA
When I saw that upper o ring when I changed oil, my thought was that it allowed me to not get oil spilling all over my hand, since it held up the oil until I fully removed the bolt. In other words, I thought it was there to have a clean oil change job, as it takes some time to remove that long bolt, and that ring keeps things dry until I'm ready to remove the bolt..
Race Director
Joined: Mar 2007
Posts: 11,402
Likes: 8,561
When the engine runs, within 20 seconds or so, any oil in the oil pan will be returned to the tank on the front of the engine. There is almost no oil in the oil pan. When the engine is off, oil will slowly (very slow) seep down to the pan, and that is why we check the oil when the engine is running. The oil drain plug, when removed allows oil to drain directly from the tank into the oil pan, and then out of the oil pan. The upper gasket, if it is missing, will allow oil to drain from the tank into the oil pan more quickly. I don't know how much more quickly. But I think it could be a problem if there is excess oil collecting in the oil pan - since it is designed as a so-called "dry sump".
