Mechanics

CHEVROLET TRAILBLAZER RADIATOR PROBLEM

2003 Chevrolet Trailblazer

The heater and ac in my car don't work unless I go at speeds of more than 40mph. The rear fans however do turn on even If the car is parked. The air that comes from the rear fan is neither hot or cold.
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Ericapadilla
December 17, 2012.




I AM ASSUMING YOUR RADIATOR IS TOPPED OFF WITH COOLANT?

(MOST EVERY OWNER'S MANUALS I'VE I'VE SEEN. TELL YOU TO CHECK YOUR OIL AND RADIATOR LEVELS. LIKE "ONCE A WEEK")

YOUR RADIATOR HOSES ARE GETTING HOT AT THE RADIATOR?

UP YONDER AT THE FIREWALL, YOUR HEATER HOSES ARE GETTING HOT WHEN THE VEHICLE IS AT OPERATING TEMPERATURE. JUST BEFORE THEY ENTER THE HEATER CORE?

IT MIGHT BE THAT YOUR THERMOSTAT IS "STUCK OPEN". THUS, NOT LETTING YOUR ENGINE BUILD UP TEMPERATURE----RATHER YOUR WATER MAY BE CONTINUOUSLY CIRCULATING AND THE RADIATOR IS COOLING. SORTA "ALL OF IT" CONSTANTLY

THE REASON OVER "40 MPH" MAY SHOW "SIGNS OF WARMTH" IS THE ENGINES CYLINDERS ARE WORKING HARDER--BUILDING MORE HEAT. AND NOW THE RADIATOR CAN'T QUITE "KEEP UP" LIKE IT WAS WHEN IT WAS CIRCULATING SLOWER AND TEMPS WERE NOT AS HIGH

THE THERMOSTAT IS BASICALLY A TEMPERATURE OPERATED VALVE THAT ALLOWS THE WATER INSIDE THE ENGINE TO HEAT UP TO LIKE 195 DEGREES----ONCE "196" IS REACHED, IT "OPENS" AND ALLOWS A SHOT OF WATER TO ENTER THE RADIATOR TO BE COOLED THRU THE TOP RADIATOR HOSE----SIMULTANEOUSLY "THAT WATER" IS REPLACED WITH COOLER WATER ALREADY COOLED BY THE RADIATOR THRU THE LOWER RADIATOR HOSE

THE WATER THAT IS KEPT AT "195 DEGREES" INSIDE THE ENGINE DOES IT'S OWN CIRCULATING THRU THE ENGINE AND SMALLER HEATER HOSES

IF THE THERMOSTAT FAILS TO CLOSETHE WHOLE DEAL GETS COOLED ALL OF THE TIME

DOES THIS MAKE SENSE---OR DO YOU NEED A BETTER EXPLANATION?

KEEP ME INFORMED ON PROGRESS

THE MEDIC


Tiny
CJ MEDEVAC
Dec 17, 2012.


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