Just my humble opinion, but if the mechanic showed an anomaly on a vacuum gauge reading then it should have been followed up with a compression test. A compression test will at tell you whether or not there’s a major engine fault or not and this can provide a clearer picture in determining whether to keep the car or sell it.
I say this because I’ve seen numerous cars diagnosed with major, expensive headaches and many times it was something so simple and cheap to repair that it was almost embarassing to be part of the profession.
While I don’t remember the details due to the passage of time, I do remember a Subaru coming into the shop once for a slightly rough idle and engine miss. Both cylinders on the right side (passenger) were not hitting and both on the drivers side were fine. The vacuum gauge showed a problem and compression test showed all was well.
The problem? A vacuum leak which due to the Boxer engine design was affecting one side only at idle and low RPMs.
At this point I would not write the car off without knowing what the compression numbers are. Ideally they should be in the 180 or so PSI range.
When I picked up the car today I asked why a compression test wasn’t done. He said it wasn’t necessary because the erratic vacuum gauge readings indicate the head needed to be rebuilt, and doing the compression test would just be more of a waste of my money. I didn’t want to argue with him, he obviously didn’t want to investigate further. And he already charged me $270 to come up with the “massive carbon build-up” diagnosis.
I don’t think I want to put any more money into this car, plus I’m running out of options on where I can take it. If I change my mind, how much should I expect finding and fixing a vacuum leak to cost? Does anyone have personal recommendations for a mechanic in the NYC area who could handle a quirk like this?
Based on what this mechanic told you about a compression test being a waste of money after finding a vacuum anomaly I can’t say that I agree with his reasoning or methodogy. At all.
A vacuum leak is generally not that hard to sort out or expensive to fix. The best method is to have the engine idling with the vacuum gauge in place and then simply go around and pinch off vacuum hoses while watching the gauge until the faulty circuit is found and/or the use of a smoke machine.
It could be that the engine has a serious problem due to lowered compression but I do not think a car should be written off or the worst assumed based on what was done and what you were told.
With an engine performance problem a vacuum test and compression test are always the first steps and it baffles me that you would get hit for 270 dollars and no compression test for that shaky diagnosis.