I have found a way to fix the valve train noise on the 603 engine, with this mod the engine runs incredibly smoother and I believe has also increased fuel mileage. what you do is remove the oil filter cover and on that cover is a tube with two orings on it, inside this tube is a small regulator valve, near the top of the tube is a small hole with the oil flowing from the small hole to the oring end, you need to drill that hole out bigger to allow more oil flow to the hydraulic lifters etc., I drilled it out to 5/32",make sure no metal pieces get into the valve and clean it out with solvent and compressed air blowing from the hole to the oring end. the cost is nothing and you can do it next time you change the oil, you will not believe how much smoother the engine will run
- posted
19 years ago