Oil Overfilled causing constant issues
Hey all, appreciate any advice in advance. Vehicle I’m referring to is a 2018 Kia Sorento with a V6 GDI engine.
About a month ago, I took my vehicle in for a tireswap and oil change. At that time, I was told the battery is getting slightly weaker but no need to replace it just yet. (Adding for context later) Getting the vehicle home, city driving, no issues. A few days later, when driving on the highway, tons of black smoke started coming out of the exhaust and the engine was misfiring frequently and the check engine light began to flash then stayed on. I pulled over and checked the oil, and it appeared to have been overfilled by a substantial amount.
I brought it back to the shop immediately and told them what happened and what I found. They checked and confirmed this was what happened and owned their mistake. They said they overfilled by about 500-600 mL, fixed it, and warned me about some more serious issues which could result such as fouled spark plugs and damaged ignition coils.
A week later, again driving on the highway, the engine starts to misfire again. It happens about 8-10 times during my drive. I bring it back in, and they confirm the spark plugs have fouled and they replace them. They also did some kind of chemical cleaning and bore scoped the engine cylinders and said they looked great. They were confident things were fixed and good to go at this point.
A week and a half later (yesterday), I have issues getting the vehicle to start. It takes me about three tries to get the engine to turn over but it finally does. One thing I noticed is some odd revs where the RPMs moved without my foot on the gas. I let it run for several minutes and it seemed fine, so I went on my way. I then got on the highway, and felt what I believed were several engine misfires and again, the engine light came on.
I take it back immediately to the shop, and I noticed as I was pulling into a parking spot, the vehicle died. All warning lights came on and I had to shift it into park and restart it to finish backing into a parking spot.
After the some back and forth, I was told based on the error code they found, they don’t believe it misfired, but there was an injector drive communication issue, code U0105. The exact wording provided by them on the work order is “U0105 LOST COMMUNICATION WITH INJECTOR
DRIVER. UNABLE TO ACCESS MODULE AS IT IS AT THE TOP OF THE DASHBOARD ON THE FIREWALL. REMOVED GLOVE BOX AND SIDE TRIM.
ABLE TO UNPLUG DRIVER. CLEANED ALL PINS WITH CONTACT CLEANER AND PLUGGED BACK IN. ROAD TEST VEHICLE. CODE HASNT RETURNED AT THIS TIME. WOULD NEED TO REMOVE SOME OR ALL OF DASH TO BE ABLE TO INSPECT HARNESS.”
Even though the code didn’t return, they test drove it and could still feel the problem, meaning it still wasn’t fixed.
I’m now being told that not only is this a fix that would take 10-14 hours because they need to disassemble the entire dashboard, but they’re saying this is a new issue and could not have been caused by an oil overfill, and the weak battery may have caused it. They’re saying they will be reasonable by not charging normal shop rates, but I’ll have to pay.
Personally, I’ve never had a single issue with this vehicle until now. I’m not a car guy, but it just doesn’t make sense to me how this issue can’t be related.
I’ve read what AI has to say about it, but would appreciate some solid human advice too. Thanks!