My 1999 mazda 626 started overheating. we have changed thermostat, flushed radiator, and it will only drive about 20 miles before it pegs the temp guage. Now it will not start.

SOURCE: engine overheating

All i can think of is the thermostat is not opening. or you may have a clog somewhere preventing the flow. Check the T-stat and hoses and radiator ( for clogs) Good luck

SOURCE: 97' Mazda 626 6cyl Overheating.

While you have it at the radiator repair shop, have them flow test the radiator. They should have information on the flow of a new radiator and then you can compare the two. They should be able to tell you if your flow rate is  high enough to do the job.

SOURCE: 98 Mazda 626 overheating. Blew off hose and was

Yes, this is most likely a thermostat problem.

As a basic explanation, the thermostat is the device which separates the hot coolant in the engine block from the cool coolant in your radiator. If it gets stuck closed, your radiator coolant will remain at near room temperature, while the coolant in your block (which is what your gauge reads) does not circulate and will skyrocket in temperature.

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SOURCE: mazda mpv overheating when driving

possible head gasket do a preasure test on the coolant system to see if it loses any coolant or presure drops and check for leaks hope this helps

SOURCE: 1999 mazda 626 wont start

truns over strong and feul pump is on but fire to cam