Same thing happened last week to my car ' date=' i seafoamed it then changed the oil , low and behold within 300 miles i had a rod knocking and i have only 100k on a gm 3800 series 2. not too many miles at all for that motor.[/quote']
You probably had hidden issues that the Seafoam brought up by cleaning the bearings, Never heard of Seafoam its self causing rod knocks.
Tell you what though, Remember Motor Up? That stuff you add to your oil that if you ever ran the engine bone dry of its oil supply the engine will keep on going?
Well I put that to the test with out even knowing it was happening. I decided to try it I had a Shelby CSX 2.2l Turbo II and this stuff was great for Turbo's helped with keeping the turbo bearings coated with hight heat synthetic material, Anyway I was moving from Oregon to Wa state and I was driving the car 500 miles since I did not want to pull it behind the moving van.
I was pulling off in Olympia to get gas and food as I was parking I could smell burning oil and my stomach hit the floor I got out the car since it was not moving was smoking as if it was on fire I popped the hood and the smoke rolled out but didnt see anyt flames, After the smoke was gone I could see Oil spray all over the engine bay and noticed the Dipstick and holding tube was GONE broke off somehow! The Gas tendant was also a mechanic and they sold stuff like this at the station so I bought a dipstick just to see if there was any oil left, There wasnt even enough to show on the stick.
After all that drama we guestimated that I drive the car for roughly 300 miles with out any oil other then what was left circulating in the engine through pressure. Motor Up saved the day, got the car fixed a day later and a new oil change and drove it fort 4 years after never once had an engine issue.
Dylan take your car to the shop that did the work on it and let them know something is not right, Dont work on it yourself and risk messing up your warranty with them, infact dont say anything about checking it yourself to them at all, Put the ball in their court.