Grandson's driving almost certainly contributed to engine failure

Dear Tom and Ray:
I have a 2003 Mazda Protege with 103,000 miles. The problem started while my 20-year-old grandson had my car one time. My engine started getting hot, and I think he ignored it, and the next time I drove it, the temperature was all the way in the hot range. I immediately took it to the garage, we let it cool and they said it didn't have any coolant. So they filled it up, I drove it home and kept an eye on it, and it was OK for a couple of weeks. My grandson took it again, and this time the car stopped completely. It would crank but wouldn't start. I had it towed back to the garage, and my mechanic says my engine needs to be replaced. My question to you is: I am 64 with not a lot of money, really living paycheck to paycheck with a part-time job. Do you think I should try to get another engine? Or should I try to save up some money and get another used vehicle for about $3,000? Please give me your opinion. And do you think my grandson's driving could have contributed to this problem? — Evelyn

Ray: I think there are two guilty parties here, Evelyn. Three, if we include you for being much too nice a grandma.

Tom: I'm guessing your grandson drove it like an animal. Now, we don't know your grandson, and he may be the most responsible person in the world, as well as an honor student and president of the Nerd Club. But if he's like most other 20-year-old males, he probably was driving the car at 90 mph and had four other kids with him.

Ray: That kind of aggressive driving really overtaxed your cooling system. I'm guessing there was already a leak of some kind before he drove it, but your gentle, and probably short-distance, driving never stressed the engine enough to make it fail completely.

Tom: But when Junior put 500 extra pounds of teenagers in the car and drove it like a NASCAR trainee, he overheated it. And worse, once it overheated, he kept driving it.

Ray: And that's when the real damage took place.

Tom: We also have to lay some blame on your mechanic. When you brought it to him the first time and it was out of coolant, he was at fault for not immediately trying to find the source of the leak. It could have been a blown head gasket. But it also could have been something even cheaper and simpler, like a leaky water pump or coolant hose.

Ray: No car should ever lose coolant without a reason. A good mechanic will find that reason and fix it before filling it up with coolant and sending you on your merry way.

Tom: If they had found the leak then, they could have fixed it and probably prevented the engine from overheating again and cracking its head or block (which, we assume, is why you now need a new engine). Even if it was a blown head gasket, and it had cost you $1,000 to fix back then, it would seem like a bargain now, right?

Ray: And the third guilty party here is you. Junior very nearly fried your engine, and then you gave him the keys again so he could finish the job. But we can't blame you for having a soft spot for the little leadfoot.

Tom: So, now what to do? If the car is otherwise in good shape, your best bet probably is getting a used engine from a junkyard.

Ray: Your mechanic can look for one for you and install it. That could eat up most or all of that $3,000 you mention. But if you can still afford it when you're done, buy Junior a $50 bicycle and tell him that's his new ride until he turns 30. Good luck, Evelyn.

(Car Talk is a nationally syndicated column by automotive experts (and brothers) Tom and Ray Magliozzi. Write to them at the Car Talk website.)