...called Valve -Kleen .. Will Engine Valve Cleaner 'Lifter cleaner called Valve -Kleen ..(CRC makes it ) kill my car , make a difference or can not hurt ? Please Knowledgable people ONLY..
Most Mechanics I've spoken to have NO clue...

Alot of cars have a protective coating at the front edge of the intake plenum,and crc which is a spray in cleaner are not recomended becase it can damage this coating.Your best bet is to find a shop that has the Snap on motor vac service or one that uses the B/G system.I have and use both depending on ease of use on a particular vehicle.A good carbon clean on a high milage engine will increase fuel milage by 8 to10%

I personally have used the stuff and it's ok. but read the directions and you'll see what it takes for the motor to consume it. The best thing you can do for your valves is to get Marvel Mystery Oil and seriously dump it into the fueltank before you fuel up. If you are concerned about your valves you may have another issue going on inside the motor to worry about. Change the oil regular and change the type fuel you run. The fuel has additives that foul up yer valves particularly in the winter. If you run the higher octane you might not see the difference until you change the brand of fuel. Try the Mystery gig for two months. use the valve-kleen if you already bought it but swap later on to the mystery oil. After summer the fuel will almost be ready to change out at the pumps. at which point you should run the highest octane you can get. Some are 90, some are up to 95.