2003 Focus SE. Timing belt tensioner froze. Junk or not?

[RossMosh]

I'm posting on behalf of my sister.

She has a 2003 Ford Focus SE with a 2.0L SPI/SOHC engine. Car has about 85-90,000 miles. The car had been driving a bit funny recently but on Friday it decided to run no longer. While driving on the highway (about 65mph) the car basically died on her. I thought it was a battery/alternator issue but the mechanic found the timing belt tensioner bearings essentially disintegrated.

Now I'm at the point where she wants to know if she should change the timing belt or essentially scrap the car. It has a 65-70mph shake and a few other problems so we're at a bit of a cross roads.

I don't want to advise her to spend $400+ on the timing belt if it's going to turn into a new head or new motor. I also don't want to tell her to scrap the car if a $400 timing belt will do the job. I wanted to take the car and yank the valve cover/change the timing belt myself, but she wouldn't let me. Now she really doesn't want to spend the money if it's going to end up a $1200+ project for a $3500 car.

What's the chance the mechanic throws on a new timing belt and the engine is healthy? I know it's hard to tell but I'm hoping someone with some SPI experience might be able to advise us.

Thanks in advance.

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