Car is question is a 1984 Supra with a 5MGE inline 6 engine, no mods whatsoever. My car developed a startup ticking noise about 3 years ago. I run my car only once every weekend for a long drive. At startup, there will be a tick tick tick noise (don't know how do describe it better, but it's definitely mechanical and coming from the engine) for about 4 to 5 seconds then goes away. Starting the car while warm doesn't do this, and it also doesn't happen if I start the car the next day. No noise either on idle. It seems to take a couple of days off to do this noise on startup. This leads me to think it might be due to the oil draining down. When it began doing this, I was running a genuine Toyota oil filter, the next year I switched to a Wix and it still does that noise. I don't think I could have got 3 faulty anti-drainback valve filters in a row over 2 brands. I've had the car for 9 years now, always ran the same oil type, Castrol GTX High Mileage 10W30. I change the oil every year, so it's about a 3000 KMs (1800 miles) interval. Engine is currently at 174000 KMs (108K miles). No noticeable smoke. The problem didn't get any worse since it began 3 years ago. What might cause this and will that damage the engine over time ?