My 2004 Cayenne S has a "tick" "tick" "tick" engine noise. Dealer won't touch it. Says I should buy a new car. 150K miles. Any ideas as to the problem and how to fix it?

If it's a "tick" and not a "knock", it is most likely upper end. Could be worn out valve springs, valves, tappets, etc.. It would require an upper end rebuild of the engine. This would be costly at a garage. Very labor intensive.

Did the dealer inspect it before telling you to get a new car? I am assuming he did, decided that the cost to repair made the car economically not viable and recommended you to buy a new car. Around the Bay Area, a 2004 150k Cayenne is worth under $10k and you may spend $5k fixing that problem. Better to sell it for whatever you can get and buy a newer one with lower miles.

Funny you should ask if dealer looked at it before they told you to purchase a new car...if they did I would expect there was a detailed estimate to fix what was wrong with the car...if not I wouldn’t trust them to take out the trash if they car...scam all the way to get you to buy new car while they get your current car for little to nothing, fix for a few $100 and resell for $1,000 of dollars...trust no one and that includes the trolls on these sites!