Are there any guidelines for determining whether "lifter tick" is because of "sticky lifters" or an actual failure of the part?
Sunday morning when I started my '01 GTP, it made a lifter tick that's easily audible inside the car, with the hood down. This is the first time it's done that, and it happened abruptly. At least I've not heard it getting progressively worse, and I don't usually play the radio or turn up the AC fan when I start the car, so I think I would have noticed.
It's a sharp tap sound from under the valve cover on the front bank, cylinder closest to the passenger side. (Cylinder 1.) Does not sound dull or coming from lower down so I doubt it's piston slap.
The sound goes away after the engine is warmed up. Could that mean it's just sticky? Or can failing lifters sound fine (for a while) when warmed up?
The car mostly sat undriven from early December until a little over a week ago. Conventional oil. It had an oil change within a few hundred miles of being parked. Oil still looks good and level is fine. Can relatively new, clean conventional oil start "gumming up" after sitting for several months?
It ran fine with no lifter noise when I started it after storage, and for the past week as I've been driving it daily, until Sunday. Now if happens every time the car sits for several hours. (In the morning and after work.)
Is it worth trying to unstick the lifter with the MMO/ATF/Seafoam in the oil technique? Or is that a bad idea? Lots of people swear by it but others say any additives like that can be dangerous.
