Hi amdixon. Welcome to the forum. My first reaction is they are afraid of getting involved with a serious problem with a car whose owner doesn't understand cars. Just like I don't understand accounting or cooking, I have to rely on the word of experts. Most owners don't understand what goes on inside an engine and that can make it hard to know who to believe and who to trust.
A head gasket definitely can be good one minute and start to leak the next. What's worse, the sensor for the temperature gauge only responds to hot liquid, not real well to hot air. That can allow the engine to overheat without you knowing it if the coolant is being burned in the engine. An overheated engine often causes the cylinder head to warp and leak, and a leaking head gasket can cause overheating. It's almost impossible to say which one occurred first.
$5000.00 to 6000.00 is too much for this repair. Half that amount would be about right to remove and rebuild the engine. They might be figuring in a new cylinder head and related parts. The old one will need machine work, will have to be inspected for cracks, and will have to be straightened. Cracks are real hard to see in aluminum heads so a special dye is used along with a black light. Unlike older domestic engines, the head can not simply be machined flat because the overhead camshaft would end up riding on surfaces that are not in perfect alignment. That will cause the camshaft to break. Straightening the head in an oven restores the alignment but is costly. For those reasons, many engine rebuilders just replace the entire head to be safe.
For even less money, you might be able to find a good used engine from a salvage yard. The good news is Toyota has very little trouble with sudden engine failure so your chances of getting a bad one from a salvage yard are very small. They generally provide a warranty with major items like engines and transmissions.
Keep in mind my experience is not with Toyotas specifically, and the last engine rebuild I was involved with at a dealership was over ten years ago. Engines are very complex now so the typical rebuild might cost a lot more than the $2000.00 I am familiar with. Still, I'm sure you can find a solution for less than $6000.00. You might consider finding a local engine rebuilding shop, and asking them for references for other repair shops that have a good reputation for quality work and treating customers fairly. They will know which repair shops insist on quality parts and which shops to avoid. (Most repair shops only remove and reinstall the engine and get it running properly. They take it to the machine shop to be rebuilt, and pick it up when it's done. Each shop sticks to what they specialize in).
Tuesday, April 13th, 2010 AT 9:46 PM