My 98 deville over heated tonight I only drove it for about 10 minutes or so it got to 262 degrees. i only had it for a 5 days.

check u r alternator

If water pump is old,like over 70,000 miles on it,replace it when you do the fan belt and tensioner.
A new thermostat and a radiator flushing might also be in order. don-ohio (:^)

It may be tough to diagnose if you can't duplicate the complaint.
When it stalls you would need to know if you are loosing spark to the plugs or fuel to the injectors to proceed with any troubleshooting.
Could be anything from a faulty relay to the coil to the fuel pump.

Sounds like fuel issue, remove the black plastic cadillac cover on the top of the engine, then find the fuel rail on top, and remove the black tire cap looking thing on the end of the fuel rail. Now you will have to get a fuel pressure guage ($45), and screw it on right there. Or you can also just poke that little valve with a ink pen to see if any fuel squirts out, it should come out with alot of force, it is like a valve on a bicycle, it only lets fuel out when you push on the valve ***. As for the battery being dead perhaps you left your parking lights on? My 97 deville, had a cold start problem, that it took 5 minutes of cranking off and on, to get it cold started, but after it was running it would start throughout the day just fine. I ended up replacing the fuel pump in the tank, and the fuel filter on the rail.

SOUND LIKE COOLANT FAN NOT COMING ON.WHEN YOU ARE IN CITY.YOUR ENGINE RADIATOR NOT GETTING MUCH AIR FLOW IN THE CITY.BECAUSE YOU STOP AND GO ALOT.DUE TO A LOT OF STOP LIGHTS.CHECK COOLANT FAN RELAY AND FUSE.IF BOTH GOOD.COOLANT TEMPERATURE SENSOR SENSOR.IF ALL IS GOOD HOT WIRE COOLANT FAN TO SEE IF IT RUNS.IF NO FAN MOTOR BAD.IF YES FAN MOTOR RUNS WIRE CONNECTOR IS OPEN OR DAMAGED.

get the battery checked

WELL THAT DEPEND BUT MOST THERMOSTATS OPEN AT 195 DEGREES SO DEPENDING ON DAY 200 TO210 NO MOOR BOILING POINT IS 113 DEGREES DEPENDING WHERE YOU LIVE IM SHERE

Have you checked the fluid level in the box?

Reverse flush the cooling system and put in fresh antifreeze to -20. (20 below zero). If that doesn't help, replace the thermostat.

if this a fuel injected car just check to fuel pressure first.