QuestionQUESTION: I have a 1992 Chevy Caprice Wagon with a 5.7L 350 V8 with almost a 193K miles, which I purchased from an individual this past Monday. The problem I'm having at the moment is the Temp Gauge likes to rise almost to HOT status. I had the A/C fixed because when i got the car the air would only blow from the floor vents. The previous owner stated he was told by a mechanic it was a vacuum switch behind the dash. I had it fixed and converted over and charged with freon. About two days later I noticed the Temp Gauge rising almost to run HOT while A/C was on but falls once you turn it off. The guy who repaired it told me that happens @ times when the A/C isn't working and then you fix it. He went on to say that it could be the radiator,water pump,or thermostat. Well I checked the car after running it bout an hour with A/C; I found no leaks from water pump or radiator in fact it was holding water well and was still full of Antifreeze. My question to you, is it the T-Stat not opening or failed altogether or something else because I have no temp problems when A/C isn't on,only when driving with A/C running after about 30-40 minutes will it bergin.
ANSWER: HI CHRISTOPHER,I WOULD SAY YOUR COOLING SYSTEM IS OK AS FAR AS WATERPUMP AND T-STAT. WHAT MAYBE HAPPENING IS THE RADIATOR IS NOT AS EFFICIENT AS IT WAS WHEN IT WAS NEW. SO THE COOLANT IS NOT CIRCULATING THROUGH THE CORE AS IT SHOULD BE..THIS IS JUST A GUESS..HAVE YOU CHECKED THE THERMOSTATIC FAN CONTROL.. [CLUTCH FAN].YOU MAY THINK THE CLUTCH FAN IS OK BECAUSE IT IS SPINNING BUT NOT AT THE RPM THAT IT SHOULD BE. LET ME ASK YOU THIS,WHEN THE AIR IS ON AND YOU ARE DRIVING DOWN THE ROAD ABOVE 35 MPH, DOES IT OVER HEAT LIKE THIS ?? IF IT DOES THEN I WOULD SUSPECT THE RADIATOR IS NOT CIRCULATING AS IT SHOULD AND MAY HAVE A POSSIBLE LAZY T-STAT... HOWEVER IF IT [DOES NOT] OVERHEAT LIKE THIS AND ONLY DOES SO AT LOWER SPEEDS OR WHEN STOPPED,, I WOULD SUSPECT THE CLUTCH FAN IS FAULTY.. YOU SEE WHEN DRIVING DOWN THE ROAD ABOVE 35 MPH YOU DO NOT EVEN NEED A FAN..THE CLUTCH FAN WILL SPEED UP WHEN THE TEMP INCREASES,THIS SHOULD BRING DOWN THE TEMP....BUT LET ME ALSO SAY THAT IF THE AMBIENT TEMP IS [REAL HOT] AND YOUR CAR WITH A LOT OF MILES ON ITS TICKER IS STUCK IN TRAFFIC THIS ENG WILL RUN HOT. REMEMBER THE COOLING SYSTEM AND ENG BLOCK ARE NOT NEW ANYMORE. SO I SUGGEST IF AT A LIGHT OR TRAFFIC JAM,, TURN THE AIR OFF AND PUT THE TRANSMISSION IN NEUTRAL. THIS SHOULD COOL THINGS DOWN PROVIDING ALL ELSE IS OK SUCH AS ABOVE.. I HOPE THIS HELPS YOU OUT,LET ME KNOW IF YOU NEED MORE INFO..ALSO IF YOU ARE DONE WITH ME, COULD YOU PLEASE RATE MY ANSWER..THANK YOU,,,,TOM..
---------- FOLLOW-UP ----------
QUESTION: First Thank You for your response to my Caprice and running hot issue. And yes I have noticed at speeds above 35mph and highway speeds it (temp gauge) starts rising to HOT. So basically I need a new radiator and t-stat,correct? Now an old notion I have heard is that if you replace your t-stat and you don't replace your water pump at the same time,sooner or later you are going to have problems with both. Is this true. If yo u could answer amd shed some light on both these questions that would be a great help!! Thx
AnswerHI CHRISTOPHER,WELL YES, I WOULD TRY A RADIATOR AND WHILE YOU ARE AT IT PUT A NEW 180 DEGREE STAT..DO NOT PUT A 195 DEGREE...AS FAR AS THE WATERPUMP AND T-STAT ISSUE,WHAT HAPPENS ALOT OF TIMES WHEN YOU REPLACE THE WATERPUMP,SOMETIMES THERE ARE OLD PARTICALS OF GASKET THAT ARE LEFT IN THE COOLING SYSTEM AND THEY CAN STOP THE STAT FROM WORKING CORRECTLY BECAUSE THEY JAM UP TH MOVEMENT OF THE STAT..BUT BY NO MEANS IF YOU REPLACE THE T-STAT YOU SHOULD NOT HAVE TO REPLACE THE WATERPUMP..NO WAY.UNLESS IT STARTS TO LEAK AFTER THAT..BUT IF IT DOES,,[[[IT IS JUST A COINCIDENCE]]] GUARANTEED !!!! LET ME KNOW IF YOU NEED MORE INFO,,,,,, TOM...
