Hello,

After watching many videos on youtube, I found myself here asking this question I have been battling to figure out, compare and make an educated decision on who to have fix my car after being screwed over few times at dealerships or local shops. The more I watch Scotty Kilmer videos, the more I dream of him diagnosing and looking at my car so I had to take a step to write m problem and hope to hear his expertise at least on the issues I am having even though I wish he was local in New York.  I would have him take a look at it in a heartbeat.

I have a 2007 Ford Mustang V6 4.0L Base model coupe car. Besides my due oil change and battery issue, I also have more complicated ones that are AC and Heater issues which I listed below as clear as I can to describe them all. My fans work properly at every level from 1 to 4 in the car when I turn it on and switch the dial from low to high, but It blows no cold at all whether AC switch is on or not. It blows no heat at any level of temperature at  dial unless i drive like 45 minutes or so and even then it is only little to no warm but it never blows hot at all. 

Regular Oil Change: Bought my own oil and filter and hoping i will have it done with the same place doing the rest of the service below for a reasonable price.

Battery: I have contacted the local auto part supplier who sells parts to local shops only and i had a pricing with bargain for a Motorcraft Battery Motorcraft Tough Maxx with 36 months warranty and 590CCA costing about $126. Or Delco costs about $30 dollars less than that. Which one would you suggest? I checked out Everstart Walmart brand but it is only 2 years warranty an about $100 and my car isn't even listed on their book, only V8 is listed. Which battery should I go for?

AC: When I had the car diagnosed, they did a pressure test I was told. and quote, "we sat there and watching the Receiver Drier (AC Accumulator i found out afterwards when I searched what receiver drier is) leaks. Needs to be replaced. Quoted for $511+tax including the labor and parts and recharging the system and make sure doesn't leak.

Heater: it was communicated with me that "antifreeze leak from thermostat housing". Needs to be replaced. Quoted for $360-$380+tax including labor and parts.

My both questions are related to AC-HEATER issues I have besides just the one question above for battery suggestion and I thought it would make sense to open one post.
My Question 1: Above I described the current problems with car and shared the quoted prices for them.
When I asked this local shop (who is very respected and known by the garage of the school I work at) about if I bring my own parts which I plan to buy at bargain at the price that they are sold to other local shops, he told me to buy my own part and bring to him and he wold put them in for me at 550+tax VERSUS $1000+ he quoted me for including the parts and labor which makes me scratch my head as I know those two parts (AC Accumulator and Thermostat Housing) costs about total of $150 or less.  Am I being asked too much ONLY to replace those two parts for $550+tax where I buy the parts and give him for my 2007 Ford Mustang V6 4.0L car. Should I ask this mechanic to make sure he includes the oil change and battery installation as well which I provide him as well with battery, oil and filter to justify his price?

My Question 2: I know the two parts pointed out to me as I listed in above question. Should I ask this mechanic about checking the blender door, or not sure what exactly it is called but to my understanding it is acting like the governor of the air distributes the air through whether AC or heating system. Because if blender door doesn't function properly, i believe replacing the two parts above won't make any difference in the existing problems with AC and Heater. Please correct me if I am wrong on that or any other part I should be concerned about.
Or do you believe I should I do one thing at  a time, change the battery and do oil change as battery may affect the functionality of the both systems, AC and heater.

UPDATE: After I had the car diagnosed, for some reason heat and AC works in every level and every temperature hot to cold but I doubt it will last. It might be working temporarily with whatever it was charged while they did pressure test (not sure what that means).

Parts Prices I found:
Four Season AC Accumulator with kit - $43.89
Motorcraft AC Accumulator with kit - $59.89

Dorman Thermostat Housing with kit - $47.99
Motorcraft Thermostat Housing with kit - $47.99

I am not an expert with cars but I know numbers and searching and hoping to get help to make an educated decision and hoping to learn more before raising the number of times i have been screwed over again.

Thank you so very much for reading this entire post. If you did I truly appreciate it. I did my best to describe as best and detailed I can after reading the rules shortly after signing up today.