WHEN I START THE VEHICLE AFTER IT HAS SET A WHILE THE VALVES MAKE A LOUD KNOCKING SOUND I HAD NEW VALVE LIFTERS INSTALLED AND IT STILL KNOCKS. ONE OF THEM COLLAPSED AND THE MECHANIC REPLACED IT BUT IT STILL DOES IT. WHEN I GET THE OIL CHANGED IT WILL QUIT FOR A FEW DAYS THAN START AGAIN. I USE 5W20 OIL IN IT AS IT CALLS FOR.
LIFTERS ARE KNOCKING on 2003 Mercury Mountaineer
check the oil level if your missing oil fill to spec also get a lucas that always works good for me may work for you too.
THE OIL LEVELS ARE FINE IF I USE LUCAS OIL ADDITIVE SHOULD I USE SYNTHETIC SINCE IT USES 5W20 SYNTHETIC THE VEHICLE HAS A 104,000 MILES IS IT POSSIBLE THE LIFTERS ARE JUST BLEEDING OFF . IT HAS EXCELLENT OIL PRESSURE ON START UP AND WHILE DRIVING.