Poured a tin of Wynn's Engine Stop Leak into a Ford Focus ST?

And now the radiator is hot, very HOT, usually in cold weather I drive around full temp on the highest fan speed and its fine, after pouring this in the engine, it was on 24.5 on fan speed 3 and it was damn hot, couldn't take it.

What's happened.

Which one of these cars would make the best first car?

I'm having trouble deciding between a 2004 Acura TL, a 2004 Acura TSX, 2004+ maxima, or an Altima 3.5 of the same year. Which one do you think is the best car for a teenage driver all around? (Efficiency, safety, & practicability)

Thank you for reading.

Added (1). @TheReal That's fair, I have changed my mind quite a bit as i'm pretty indecisive with some stuff. However I can get my class 5 (GDL) in about a month and a half and i'm hoping to get one of the cars listed above.

@ANDRE L i have calculated all of the expenses (including insurance and fuel) for each of these cars and i make more than enough to be able to own them. I'm not interested in a Ford Focus or an "older economy car" otherwise i would've listed it above

Inherited a car don't know what to do with my other car?

So my grandpa passed away about a month ago. He left what he had left to my grandma, my aunts, uncles, and cousins. He left me his 2012 Honda Accord. I'm really honored as we always talked about cars in general and I helped him pick out this car. He had financed it and had GAP insurance on it and since he's now gone the car is mine free and clear.

The problem is I'm so emotionally attached to his car that I must keep it and drive it forever (I mean its a Honda with only 12,000 miles). I also have a car of my own that I've financed about a year ago (2014 Ford Focus). I feel that I should sell my car but I can't because its not paid off. I also can't drive both cars. I do have a best friend who lives in a different state for work but doesn't have a car, can I give her my financed car and just pay the car note still? I'm so confused!

Do I have to add the finance price to the listing price?

So I'm currently looking online for a car. I saw that there's a 2012 Ford Focus available and the list price is $13,409. However, under the list price it says the finance price is $6,998. I'm not sure if that means that that will be the price of the vehicle if I finance? Or do I have to add the listing price and the finance price together and that would be an estimate of the amount I would pay when I'm done financing the vehicle?

Is it better try sell at Carmax or a Dealership?

I have a 2014 Ford Focus SE sedan that has about 23,000 miles. It is in a very good condition. I'm planning on selling it soon but I still owe about 12,000 to the bank. How does this process work if you still owe and is it better to sell at Carmax or a dealership?

Ford focus roll back issue?

I took my focus into the dealership (its an automatic) because of dangerous roll back on hills (between 6-10 feet). I was told that it is Normal for the car to roll back and they sent me away. I have had the car a year and have had several instances where the car nearly rolls into the car behind me. Would I be at fault in an accident? Could I sue ford if i'm found to be at fault? I'm really worried about rolling into another car.

Added (1). the car rolls back in drive.

Added (2). the car rolls back usually when i'm at a stop and begin to accelerate. I give the car gas but the transmission won't engage. I usually end up peeling out when the transmission finally grabs. I have had 5 automatic cars and i've never had this happen before. Even modern standard transmissions are made with an anti roll back feature.

Added (3). To all you people suggesting holding my brake with one foot and the gas with another, my grandmother actually failed the drivers test because they said you can't drive an automatic with two feet. And as i said, even manual cars don't roll back anymore.

Marvels Mystery Oil Added?

I added a quart of Marvels Mystery Oil to my car so I can keep my engine clean and to help quiet my lifter tick. It has done a great job cleaning it as the tick is barely there anymore. But I recently see my car is kicking up a lot of smoke lately from the exhaust. It is white/gray and I have heard it is from cleaning the engine kind of what SeaFoam does. Has anyone tried this?

I also replaced my PCV valve as well and added an additive to my transmission to help it. I love my car, it is a 2000 Ford Focus with a 2.0L SOHC.

Ford Focus won't start up?

When my dad bought it, the diesel pump was said to be knackered, so my dad bought a new one and had it fitted. But it still won't start up. You can hear it turning over, but it won't kick in.

We tried spraying 'easy start' into it and it starts up, then as soon as it burns it off it cuts off.

Any ideas why it's not starting up?
Thanks!

Added (1). It's a 2003.
Yes, there's fuel in the tank x