Re: replaced thermostat but after awhile when it has been
Did you "bleed" the air from the system after replacing the thermostat housing? On some GM vehicles, there is a brass "bolt" threaded into the housing. Some models will develop an air-lock, which prevents the fluid from filling all of the coolant cavities causing "cavitation" - which can lead to an overheat condition. If you can find the brass bolt (usually located on the thermo housing, but sometimes on the waterpump hose assembly, remove it while the engine is warming up. As soon as air bubbles cease coming out and a steady coolant flow is seen, re-insert the brass bolt.
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This is s common fault after replacing thermostat, there is a system bleed screw located on radiator which will need bleeding? If you warm engine up"only warm not hot" then locate bleed screw and slacken off, not unscrew all the way? You will hear a hissing noise of the air in you system. Very similar to central heating radiator in a house! Once you have water coming through then tighten up bleed screw/bolt and give engine a bit of a run. Hope this helps
If you take out the thermostat and put everything back together without it, you should see the water flowing in the radiator, if not, replace it. Assuming that the belt isn't loose or anything. But after everything you've said here, I'm saying water pump.
Heating up while idling for long periods is normal, so is cooling a little when accelerating as the water pump is moving the water a bit faster. As long as it drops to normal temp when in normal use it is ok, if it overheats either your thermostat is faulty or your electric fan is not coming on when it should. Does the elecrtic fan ever come on?
WELL YOU NEED TO DRAIN COOLANT LEVEL BELOW THERMOSTAT LEVEL.YOU HAVE TO DISCONNECT MAF SENSOR LOOSEN AIRDUCT 2 LARGE CLAMPS LOOSEN REMOVE 4 SCREWS TO AIR FILTER COVER LIFT UP REMOVE COVER. THEN REMOVE AIR FILTER AND HOUSING, FIRST DISCONNECT MAF SENSOR.YOU HAVE TO DISCONNECT THROTTLE CABLE AND SHIFT CABLE.YOU HAVE TO DISCONNECT REMOVE THROTTLE BODY COOLANT HOSES DISCONNECT IDLE SPEED CONTROL VALVE CONNECTOR AND DISCONNECT TPS SENSOR CONNECTOR. THEN REMOVE THROTTLE BODY ASSEMBLY. YOU NEED TO BUY NEW THROTTLE BODY COOLANT HOSES AND NEW THROTTLE BODY GASKET FOLLOW TOP COOLANT HOSE TO ENGINE BLOCK.NOW YOU SEE CAN AND REMOVE THE THERMOSTAT HOUSING REPLACE THE THERMOSTAT.BESURE TO HAVE EXTRA COOLANT ON HAND.BLEED COOLANT SYSTEM WHEN DONE.TO BLEED COOLANT SYSTEM REMOVE RADIATOR CAP ON OVERFLOW JUG.THEN OPEN BLEED SCREW ON THE WATER PUMP BYPASS HOSE PIPE JUST A LITTLE.POUR COOLANT IN THE OVERFLOW JUG UNTIL LEVEL STOP DROPPING.STOP AT COLD MARK ON JUG.CLOSE BLEEDER SCREW ON WATER PUMP BYPASS HOSE PIPE.CRANK VECHICLE CHECK FOR LEAKS. START UP ENGINE LET IDLE FEW MINUTES THEN CHECK COOLANT LEVEL ADD MORE UNTIL UNTIL LEVEL STOP DROPPING.PUT RADIATOR CAP BACK ON OVERFLOW RESERVOIR. LET ENGINE IDLE WATCH COOLANT TEMPERATURE GAUGE.WHEN GAUGE START CLIMBING. TURN OFF ENGINE WAIT FEW MINUTES TAKE A LARGE RAG OPEN RADIATOR JUST A LITTLE YOU HEAR HISS NOISE.WHEN PRESSURE STABILIZE DONT GET SCALDED BECAREFUL.OPEN CAP LITTLE MORE.IF COOLANT PRESSURE STILL BOILS OUT WAIT 20 MINUTES ADD MORE COOLANT TO RADIATOR OVER FLOW WHEN COOLANT LEVEL STOP DROPPING.PUT RADIATOR CAP BACK ON START VECHICLE UP LET IDLE UNTIL THERMOSTAT OPEN. THEN FEEL TOP RADIATOR HOSE FEELS HOT THERMOSTAT OPEN WATCH TEMPERATURE GAUGE.IF GAUGE TEMP START CLIMBING TURN OFF ENGINE WAIT A WHILE.CHECK AND ADD MORE COOLANT.WHEN THE ENGINE CAN IDLE TEMP GAUGE STOP CLIMBING YOU HAVE BLEED COOLANT SYSTEM.KEEP CHECK ON COOLANT LEVEL.
Yes, could have air traped in the system, but from my experience this only gives a false indicator of being hot. When I see a car overheat I think thermosat,fan, radiator cap, or headgasket/craked head in that order. You have already changed the thermostat, so the nest thing to check would be the fan clutch. You can check this by spinning the fan when both hot and cold. When hot it should get very hard to spin- I like less than one revolution when given a good spin.Also a good indicator of a bad fan would be if it gets hotter in town than on the highway. On th e highway you get ram air that helps to cool it down. Radiator caps need the gaskets inspected for crackes and hardness. If crackes are present or to hard they won't seal causing the radiator to overflow. They should also be preasure tested by a local shop or parts store. If the preasure is to low this will also alow the car to heat up quicker and also allow the radiator to empty at a lower temp. The best way to test for a cobustion chamber leak is at a shop. Many shops can test for this right at the radiator with a special dye that will change color in the presence of combustion chamber gases in the collant system. You will notice that I never metioned water pump even though you already change it. Water pumps either pump or they leak, very rarley will they not pump water causing an overheating problem. The only way they will cause an engine to overheat is if they loose the ability to pump water through the loss of the impeller or a broken shaft- or on the very rare occasion an impeller that has run so long that it is worn out.
hello , sounds like an air lock in coolant system , drain system and re fill very very slowly , if you think you are filling it slowly enough slow it down even more , also replace thermostat to ensure its opening and closing properly , hope this helps
The radiator cap is at the radiator where you refill the radiator with coolant. Unless it is leaking and you hear a hiss. It may not have anything wrong.Neither will the water pump.If the water pump is bad. It has a small hole that will make it start leaking .Check the engine for leaks at the intake or the water pump.You will know where it is leaking. When the thermostat was removed and hopefully replaced , did you bleed the system ? The system has to be bled to remove air pockets. Or the engine will overheat again. Also check that the radiator fan or fans is turning on . If not you may need to replace the temperature control sensor.(TPS)