Strange water hammer/turbulance from kitchen faucet when water gets hot.. sometimes

[idratherplaytennis]

I have one of those classic wall-mount Price Pfister faucets that have been in use for decades. The faucet is new as of a couple years ago, mostly in use from the last half year and this has been a recurring problem under certain conditions. When I take off the original aerator (which had a bad manufacture and in addition to the stream, shoots some water way off to the side) and put on an aerator which is a combo spray/stream (and this has been tried with a couple different aerators of the same make from the water company (from their water efficiency program), a hammering effect can be heard going the length of the pipes under the house back towards the water heater, only AFTER the water at the faucet gets hot enough. The cold causes the same phenomena until the faucet cools down.

This only occurs with the spray/stream aerators and to my knowledge, the washers are all tight. This has been an ongoing problem since it was new, and I just dealt with it by using the original stream aerator that sprays water all over the place when it runs, and I got tired of it and went back to the combo aerator which was fine for about a week before the hammering issue returned. I'm wondering if anyone has any suggestions or fixes- if maybe because it's a reduced flow aerator that has something to do with it (although I'm puzzled why it only happens when running the hot water and not the cold water). I'm going to shut off the water today and recheck the washers in the neck of the faucet and around the hot and cold stems, but I'm 90% sure they'll still be fine and snug- not loose causing the vibration issue. If I need to purchase a different one, I'll go and do that, but as it happened on multiple aerators, I'm hesitant to get a third or fourth as it may be.

Any advice is very much welcomed since my plumber is out of commission having just had knee surgery last week.

 

[idratherplaytennis]

I figured I would update this really quick in case it helps- I took off the stems and the head and the washers and o-ring are all snug. I'm not totally used to the wall mount faucets but apparently they have no seats, and the area where a seat would normally go (on the hot side) is looking like bits are missing on the inside area where the water flows from. The faucet shuts off perfectly without having to crank down on the handles each time the first time with no drips, but I'm wondering if the area of the seat that isn't perfectly smooth is causing turbulence when the water gets hot, which then causing the water hammering effect.