My son has a 2000 Vitara 1.6 auto 4x4.  While sitting in a drive-through or at a long light, the engine stalls and fails to restart.  It doesn't loose coolant.  He can feel heat on his legs before it stalls but, didn't make a note of the temp gauge.  It does start after cooling down.  I'm going to replace the thermostat, air filter, and spark plugs.  The fuel filter only has 10k on it.  Is there anything else I should look at?

Can you do a compression test?  You might also want to check the oil for water.

Can you do a compression test?  You might also want to check the oil for water.

We just changed the air filter and spark plugs.  Filter was pretty dirty.  Spark plugs looked great altough the gaps were at .050.  Every plug looked exactly the same.  Smooth tan metal parts with light purple on the ceramic.  The oil and coolant always look clean and smell as they should.  I need to see if I still have all of the parts for my compression tester.  Haven't needed it in a very long time.  Is there a problem with running without the t-stat?  I've done it with carbureted cars in the past.

Sometimes they run hot, sometimes they run cold.  Depends on the motor, I'm not sure how Suzuki's handle.

You should be able to test the current one though by dropping it in water.

Check the fan clutch or electric fan sensor.

When does it seem to get hot and then fail to start?
Sitting in town traffic or on the highway?

Check the fan clutch or electric fan sensor.

When does it seem to get hot and then fail to start?
Sitting in town traffic or on the highway?

It gets hot sitting at a long traffic light or waiting in line at a fast food drive through.
I can feel some drag on the clutch fan.  What's the best way to test it?  Just see if it's turning while the engine is running or use a gauge?

The fan clutch should lock the fan to direct drive when the radiator is hot,
if it's overheating when the trucklet isn't moving, I bet it's the clutch.

Let the engine start to get hot, then try to stop the fan with a gloved hand
or something that can bring the fan to a stop without injuring yourself, if
it stops and you can hold it, it's a bad fan clutch

Wild

Could be a problem with the camshaft position sensor or crankshaft position sensor, does the Check Engine Light come on when it stalls?