Professionals don't fix things with pliers on hoses. We might DO that during service procedures or as part of a test or diagnosis, but we would never let a customer take any car, including their own, like that.
My advice is to return the vehicle, get your money back, but explain that you still will buy it once it is repaired properly. When they tell you it's fixed, ask to take it for a couple of hours to have a mechanic of your choice inspect it. That should be standard procedure for anyone buying a used car. A lot of shops offer this service. Expect it to take about an hour and cost around $100.00. That is a dandy investment that could stop you from many years of heartache. There's no country goat-ropin' song that compares to the misery of being taken advantage of with a used car.
Do not let the selling dealer tell you which shop to take the car to. Many used car dealers don't have their own repair shops. They contract out to other independent shops. You could end up taking it to the same shop that did the shoddy work in the first place. Also, a selling dealer and the people at one independent shop could be friends, and they'll stick up for each other. You don't need that. A repair shop and the dealer could be enemies, and the mechanic at the shop might intentionally call something defective when it really isn't, just to make the dealer look bad. You don't need that either. You want an unbiased opinion, but also be aware that what one mechanic warns you about that "could become a serious issue", another mechanic might correctly dismiss as a minor inconvenience. Older and more-experienced mechanics generally have a better feel for what wear and tear is normal and acceptable. Many inexperienced mechanics might not notice something that could turn serious, but it's often those lower-paid mechanics who get assigned to safety inspections. Your best approach is to leave whatever car you showed up in at the dealership, (so they know you're coming back), tell them you're taking the vehicle to be inspected, but don't tell them where you're taking it.
If the shop identifies some things that need attention, ask them to give you a written estimate. You can use that for bargaining with the dealer. If there are things you can repair yourself, that will save the dealer some money and they may be willing to adjust the selling price to reflect that. The repair shop will often be happy to take care of those things after you buy the car. They want to earn your trust and repeat business, and this is one way to turn you into a happy customer.
When you get to the shop, (you may need to make an appointment), they don't have to know who the dealer is, but you should give them the recent history and problems. Every mechanic will pull off the wheels to inspect the brakes. They'll look at the exhaust system, steering and suspension systems, and they'll go for a test-drive. Beyond that, if you don't specify anything, there are a huge number of things that do not get looked at simply because it is not practical to tear everything apart and rebuild the car. Some of those things you should check yourself first. Do the seat belts retract smoothly? Are the seats straight and level? Do all the power accessories work, like power mirrors, power seats, power locks? A rear window defroster grid really needs to be checked with a test light in summer to verify every individual grid line is working. One or two dead grid lines is hardly a reason to whine and snivel, and that can easily be missed by the dealer's inspection, but those are easy to fix. You just want to know the rest of the system is working. Look at the condition of the weatherstrip around the doors. If there are tears or chunks missing, there are going to be water leaks and / or wind noise. Be sure the wipers work on all speed settings and the switch doesn't feel loose. The yellow anti-lock brake warning light, (if equipped), and the red Air Bag light should both turn on for about six seconds when the ignition switch is turned on, for a bulb check, and that is when those computers are running their initial self tests. Neither light should ever turn on while driving. If one does, that computer detected a problem that must be addressed. If the dealer balks at your taking the vehicle for an inspection, they have something to hide. If they are proud of their product, they'll be happy to have its quality verified.
Ask the dealer what they know about the car's history, and what repairs and services they performed. A lot of perfectly fine cars go through auctions that only dealers can buy from, so they won't know anything about them, but they will know what repairs they did. A lot of cars come from rental agencies at airports. Those are well cared for and are taken to auction often by the time they have only 15,000 miles on them. They get them from the manufacturers at real good prices because the manufacturers want people driving their cars when they are almost new. Makes for more sales if the drivers liked them.
A lot of new-car dealers will trade-in anything toward a new car, but they don't want to bother with trying to bring an older car up to their standards to be on their used-car lot. They'll send those to an auto auction where used-car dealers who specialize in that type of vehicle will buy them and put the time and effort in repairing what is needed. You have to expect things like worn rubber pedal pads, tears in the upholstery, and blotchy paint.
One last point about any used car. Every single car every built is going to have something break. At issue is when and where is it when that happens. Something can break the day after you buy the car, and obviously the dealer had no more ability to know that was going to happen than you or his mechanic did. This is more true today with all the complicated, unnecessary electronics and technology. The worst possible environment for delicate electronics is where there are high temperatures, wide variations in temperatures, vibrations, dust, and moisture. That is exactly what is encountered when we plant these delicate computers in cars. It's a miracle there are as few breakdowns as there are, but when something does go wrong, please do not automatically assume the dealer knew it or "should have known it". The same thing could happen to you when you sell a car. You may have had not a single problem in the last year, then the buyer has three things break in the first week. Some things just break, and we have no control over when that happens.
Monday, June 20th, 2016 AT 9:19 PM