I grew up running around my Uncles place which was an old fashioned Garage. He made stuff for cars on machine tools.

Never would he nor I for that matter - and I only do my own stuff - say what was causing a problem without first examining the vehicle! 'It'e the or change or what ever ...' is the first and last thing I will hear from a so called mechanic.

A good thing is to take it to a small reputable repair man and simply ask will you diagnose this problem I have - they mostly comply and charge 20 bucks for time - then you can get an estimate for the repair, which if you leave it to the same place gets the 20 back into the final bill.