declinetostate
New member
I pulled my valve cover off and i can see some blue heat discoloration on my camshaft. I see it next to three cam bearings. It is only seen on one side though. The color isn't on any of the bearing caps and all of the lobes are shiny and clean with no signs of heat. There is no sign of burnt oil residue anywhere. The truck is a 2001 isuzu npr with the 4he1 engine. Other than cold weather starts without the block heater the engine runs well and starts on the first crank. The truck has 165000 miles on it. I purchased it with 155000 miles so im not sure of its history. Have any of you seen this when adjusting lifters? Im afraid its a bearing issue from overheating but i think id see more damage or a larger heat affected area. It's all less than an inch out from the bearings and only on one side. Any thoughts? I have pictures on my phone but im not sure how to upload them.