My Fit is now at 72,000 miles. After getting trouble lights for upper and lower O2 sensors, I dropped the intake manifold and replaced them, the plugs and adjusted the valves very painstakingly. I can now attest as others have that a clattering valve train at idle, to some extent is normal for the Fit. At best it sounds like a perfectly tuned sewing machine but it can change, such as after you have flogged it and then stop and idle. the car runs magnificently and is getting the best fuel mileage ever. Thickening the viscosity is not the answer, in fact I have concluded that running 0W-20 Mobil 1 is probably best all year-round. It is so easy to get freaked out by the valve train sounds on the Fit and, if you know your valves are adjusted properly at a certain point and running good synthetic oil, you can wring it out quite a bit for quite a long time without worry. Remember, it has roller tappets...

 

Still, you need to manually check clearances to verify that the valves are adjusted properly. Don't ASS-U.M.E. that everything is in spec because you have no issues or noises.


Case in point: at 50K miles I checked our CR-Vs valve clearances (K24 engine)...they were VERY close to spec. Only had to adjust 3 cylinders, just by a little.

At 60K miles I checked the Fit. EVERY cylinder needed to be adjusted, some more than 3 thousandths. The exhaust valves were all tight , the intake valves were all loose.

Roller rockers or no, I'm going to check the Fit's valves again in a year (another 20K), just to assure myself that they are OK.