Hey guys. First time posting but I have spent numerous hours reading through the forums. This place came in handy when I did my 5100's and new rear leafs.....I have an 04 DC with a 3.4L. It has about 125K miles. I park my truck outside over night and on some of the cooler mornings I get a knock when I first start it. It only last a few seconds. I have never heard the knock any other time. I am currently running Mobil1 5w-30 with a Wix filter, but I have tried Valvoline full synthetic in 5w-30 and 10w-30. It doesn't matter what oil I run, I still get the knock when I start it on cold mornings. I am only talking about 50° or colder, so not very cold. I really don't think it is a main or rod bearing. Is there something else it may be?
Any feedback would be appreciated.