i wanted a dump valve before i could drive lol from the age of about hmmm 13yrs.... now i got it and the ability to sort out any running problemsthat may occur. however its just that when you said someone told you that it could cause a piston to melt it slightly annoyed me. he oesnt know what he is talking about. what type of engineer are you,MECHANIC? The way you said it in your post sounded that your car was slightly faulty but no is more faulty, and i believe this is simply not the case.