This could be your hydraulic lifters making this sound. The lifters get pumped up by oil. Sometimes the hole the oil passes through gets clogged and won't allow them to pump up. Sometimes they will make this noise when the engine is low on oil. The valve train is the furthest thing from the oik pump/sump, so they are first parts to be oil starved when your vehicle is low on oil. I have included some materials on the subject from the vehicle manufacturer in the diagrams below. Please go through them and get back to us with what you find out.
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Friday, March 8th, 2019 AT 2:35 AM