Q: The mechanics is saying to change the Brake pads and engine mount replacement cost $550. is this worth to repair the car or sell

You have an "older" car but one with relatively low mileage on the engine. (My car is 26 years old, so don’t feel bad). The big issue with "older" cars is corrosion and deterioration of critical rubber products like valve stem oil seals, engine gaskets, and suspension bushings.

As far as corrosion is concerned, if you take a look at the brake tubing and fuel line tubing underneath the car, if these tubes are encrusted with corrosion at any point in the lines, you have to give this current proposed repair, and its cost, some serious thought. (Encrusted means there is much more than just surface rust but rather the surface of the steel tubing is pock marked and looks like the surface of the Moon; "surface" rust is acceptable; the tubing surface will still feel smooth).

If there is a lot of serious corrosion on critical components like brake and fuel lines, you have to consider the possibility that "soon" the car is going to require major restorative work (e.,g., on my 26 year old car I have had to replace every single steel tube due to corrosion, not an easy job; if you replace with Nicopp though, as I did, your new tubing will outlast you).

Essentially, you are asking an economic question but one where the answer will vary depending on the current condition of the rest of the car (as discussed above using corrosion as an example concern), the cost that you can get required, essential repairs done for, and the cost of the alternatives in terms of buying another car. To give you an idea of the complexity, even if your brake and fuel lines are corroded (but are not yet leaking) if you can get the motor mount and brake pads fixed at a low enough cost, that means "keeping" the car could be an economical (low or lowest cost) option. This, indeed, is something YourMechanic can help you with as YourMechanics are independent and can offer you savings on labor costs as well as give you good advice as to your options.

Of note, you mention "brake pads" as a recommended repair. But, excepting the case of a practically "new" car, brake pads cannot be just switched out without, at minimum, ensuring that your caliper and the caliper torque plate sliding pins are functioning. On a 20 year old car, it is not likely that these parts are serviceable and consequently, your new brake pads will promptly wear out because your caliper is sticking. Also, you cannot apply new brakes pads without either turning the rotors or buying new rotors.

The engine mount, too, has to be evaluated and the diagnosis confirmed. You refer to "a" mount but there are several mounts on your engine and if one is bad, I would wonder what the condition of the others is.

In your particular circumstance, I would recommend that you have a trusted, competent and interested expert, like one from YourMechanic, assess your entire car and give you enough information in total such that you can make a decision as to whether to keep or replace. Again, you have to weigh and evaluate quite a number of factors, not to mention a final decision always depends on how inexpensively you can have any immediately required, that is essential, repairs done. Let us know how we can assist you.