i put 5w30 synthetic in my park ave, it leaks like heck now but oh well it will be gone soon, i use 10w30 valvoline generic oil in the bonneville and a ac delco filter, gets changed every 3000 kms, and come winter i use 5w30, i use it fort viscosity reasons.

i use valvoline max life 10w30...and then i put that restore engine horsepower...which is like 8 bucks a can...i notice that that helps....its a cool color too its blue...try that...

That can of restore is the only 'mechanic in a can' that ever worked for me. Good stuff, but only works for one thing: Scored cylinder walls. Won't do a thing for valves, seats, rings. You've got pretty good odds of it helping at least a little bit on an older car, but you'll need to use it about every other oil change to keep it working.

Hi

Synthetic didnt cause the leaks, it likely only cleaned away the gum and deposits of dino which was masking the damaged seals.

Val is one of the oils which hasnt done very well in UOA. If you want to use dino, try Chevron if you can get it.