My brother has a 2018 that he bought brand new. During the warranty period, his MIL lamp illuminated, and it turned out to be a faulty/failed connector at one of the injectors. It was repaired by a local dealer at no cost. He has since had the same failure occur several times, at different injector connections, (out of warranty), which he has had to repair at his cost. After 2 or 3 more, he began ordering the replacement GM connector/pigtail service parts from the dealer, (over $100 a pop), and replacing them himself. His dealer stated the connectors become contaminated with engine oil and lose their integrity over time. His first time doing the job himself, it took him over 5 hours. He just did his 3rd or 4th one this week, and he has it down to about 2 hours depending on which cylinder bank the bad one is on. Total of 7 times, this latest one was a repeat of the first one that the dealer replaced under warranty. He said the factory connections are crimped, but he has begun soldering them, for better connection integrity. I don't know if his particular Duramax is just a lemon, or if others are having the same issue. It sure seems like a defective design, (or crappy components), and if it is a widespread issue, GM should fix it. I am guessing they redesigned something for that L5P version, because my truck is a 2015 LML version, and has not had any such issues. Anyway, just wondering if any of you guys with L5P trucks have had this happen to you?

Well, I don't know about the connector, but if it were me and they kept failing, I would change my suppler. 2nd thing, I am not paying $100 for a connector i can get for $4.

https://www.rockauto.com/en/ca...ector+connector,2577

Joe

Yeah Joe, I told him about Rock Auto, and he did order 8 of them to cover replacing all of them again, he said it was a little over $30, but when he got them, they are apparently a chinese generic version. I told him they can't be much worse than the GM parts he has been buying from the dealer...

Just spitballing, but if the connectors are getting contaminated with engine oil, couldn't you fill the connectors with Dielectric Grease to keep the oil out?

Joe

Not a bad idea, Joe. I will pass it along to him. Apparently these connectors are bathed in oil, or exposed to it. Possibly inside the valve covers or upper valley of the engine. I haven't any idea, just going by what he told me.
I was mainly interested to hear if ANYBODY had ever had such an issue, because I don't know of anyone else who has had this happen, with ANY year Duramax, and for one truck to have 6 of the 8 injector connectors fail, (one of them twice), seems really strange. A thought that just popped into my head, is I wonder what oil he is using, and could it possibly have an additive in it that might cause the problem?
I have heard similar deals about some of the many high-mileage oils that are everywhere these days. That some of the additives they contain to soften up seals and supposedly cure leaks, actually cause major issues by dissolving some O-rings, gaskets and seals, as well as forming varnish. I consider them all to be "snake oil", because I don't think you can correct mechanical wear issues with a chemical solution.
That being said, I don't know if they make High mileage diesel oils, (I'm sure they do), nor do I know what he is putting in his truck. I'll ask him about it.