VL Turbo making a weird rattling noise from the engine bay
just bought a VL turbo and theres a rattling noise from the engine bay when the car is cold. goes away after about 5 minutes of driving. mechanic reckons its probably nothing but it sounds bad. anyone know what this is? the RB30 has 180k on it and seems to run fine otherwise. boost feels strong.
timing chain rattle on cold start is super common on rb30s. the hydraulic tensioner takes a while to pump up when the engine has been sitting. use a good quality oil and it usually settles down. if it doesnt go away after warmup then the tensioner might need replacing. its not an emergency but keep an ear on it.
same thing on the rb20det and rb25det. its the chain tensioner. use 10w-40 fully synthetic and change it every 5000km. the rattle will get shorter as the tensioner stays pumped up better with fresh oil. if it gets worse get the tensioner replaced before the chain skips a tooth.
Cold start rattle that disappears when warm is classic hydraulic chain tensioner behaviour. As others have said, fresh oil helps. The RB30 is a strong engine and this isn't unusual at that mileage. Just monitor it and if the rattle duration increases over time, budget for a tensioner replacement.