What is causing valve train rattle when I first start the engine from cold start
When I first start the engine I hear a loud valve train rattle for about 1 to 2 seconds. I get this every time the cars sits off for about 3 to 4 hours. Once on the car is quite and very smooth. I change the oil religiously every 3K and only use Mobil 1 synthetic.
There is clearance for the moving parts so when the engine warms up and oil pressure builds up, then the engine quiets down.
Cam chain rattle until the oil pressure driven tensioner takes up the slack in the chain.
Try adding some Lucas Engine Oil Stabilizer for synthetic oil. No promises but it my help.
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