Alexey Mukhin

Hi there, I have a 2018 c300 with 43k miles on it. I recently finished rebuilding the engine on this car and all is good besides one thing. The hpfp is ticking or rattling. Now this issue only starts as the car starts to warm up. When it's cold and you start it there is no noticeable or audible sound and when reving the engine all sounds healthy. When listening to the pump with a stethoscope you can hear some metal clicking, almost like the cam follower is nice and loose in there. However replacing both the hpfp and the cam follower yelled no results. If someone might have an answer or a possible solution I'm all ears. Also to note, the car was flooded and the engine was hydrolocked which caused the rod to snap and break the block. That's why I was rebuilding the engine from ground up( new rods, pistons, rings, valves, turbo core, gaskets and seals)

Cosworth2000

Is it loud when it hear it or you can just hear it?
Some techs like to change the oil to a heavier oil and some like to change it to a lighter oil when what the car would usually use.
As engines get older they normally tick but don't rattle.

Let me also add.. that that must have been a really big job.. Why to go!