Rattling Valves?


I am trying to keep my '97 Toyota T-100 as long as I can. It has been running like a champ for 150,000 miles. I just had all fluids changed and valve cover gaskets replaced. It hasn’t given me any trouble around town since that service.

On a recent trip I began to hear rattling after driving at 70 mph for about an hour. Rattle only happens at over 2800 rpm. There’s no noise in neutral or with clutch in (not a loose floppy kayak strap).

Shop uses 10-30 oil, because it gives better gas milage than higher vis. stuff. Could a higher viscosity oil silence rattling valves? Any other ideas what might rattle after warming for an hour?

Shop wants to hear noise. I’ll have to drive a half hour away to get it to do that again. Thanks


Use only the viscosity recommended in the owner’s manual.

That noise you hear could also be a timing chain. Wait and see what the shop diagnosis is.


The expression “valve rattling,” is nearly always referring to pre-ignition. If the sound is similat to a tin can with several B-Bs being shaken around, try a tank of high octane.


which engine? 4 has chain, 6 has belt.


Manual recommends 10w30, but that was for a new truck.

It has the six. I had the timing belt replaced about 30 k ago. Didn’t rattle after that.

If octane is the problem, wouldn’t it happen all the time, particularly when I accelerate sharply? We pay the highest gas prices in the US. If the only way to get rid of noise is to fill tank at $4.30 a gallon, I’ll live with the knock. Yea, I know I’ll be paying $4.30 a gallon for regular next month.


Have the valves been adjusted anytime this decade?