If you are thinking about buying a car or truck in Paraguay, STOP. The short advice is that don't do it. At least don't buy anything used. Spending years in Latin America has thought me that don't trust a soul when it comes to any vehicle and that includes bicycles.
Mechanics here are absolutely worthless, they don't a have a slightest clue how anything works and their favorite tool is a hammer. I'm an engineer and I can't tell you of the horrors I've seen in this country.
A lot of cars are imported from Chile which are originally Japanese with right hand steering. They chop the cars and change the steering to the left and sell them down here. Every Steering change I've seen is ungodly unsafe, horribly done, and an accident waiting to happen.
Then there are cars that were sold here originally which they have a part from every manufacturer known to man. Don't be surprised to buy a Chevy with Toyota motor in it, Mitsubishi alternator, ford seats, and Nissan bumpers.
People don't care about their cars here; they just want them to work, no matter what, and as inexpensively as possible. Cutting corners is the attitude here. When things go wrong and it need to be fixed properly (properly means actually spending money), they put a Band-Aid on it and they put it up for sale. 90% of used cars for sale here are absolute garbage.
If you look on Clasipar, you'll see that every ad says Impecable. Either Paraguayans don't know what Impecable means, or blown head gasket, seven accidents, crap tires, and smoking to high heavens means the same as Impecable in Spanish.
And don't even think about taking a mechanic with you to checkout your car. That's like taking a wolf to choose his prey. A while ago, I was in market for buying a Turbo Diesel truck here. 9 out of 10 trucks I looked at had a blown Turbo and the owner always said on the phone that the turbo worked perfectly! One of them was a mechanic and I had to explain to him what Turbo actually does.
The bottom line is, either buy a brand new car here or import one from the US. The shipping and Aduana fees are worth it. Even you buy a $1000 car in United States sight unseen, I promise you it will be in a better shape than a used car here.