hello. i have a 1996 1.4 astra. the temperature gauge goes into the red 100 deg c and the fan doesnt cut in. i dont know if it works or not because i turn the car off before it goes any higher but i assume the fan would be set to cut in below that temp? any help appreciated on what to check? c8hep@aol.com
thanks
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put a new switch into the radiator
be aware you may end up needing a new radiator if the poor quality metal ring in the plastic radiator decides not to play ball
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id have suggested checking the fans work first by shorting the wiring plug to the rad switch with a bit of wire, if the fans work then replace the switch
chris
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Shouldnt be going that high with or without the fan cutting in at this time of year unless you are doing a lot of stop start driving with no airflow over the rad.
Suspect bigger cooling problem. radiator, thermostat, water pump or even head gasket are all suspects imo.
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fan should come on at 98 degrees
this is the first thing that fails on these old vauxhalls thats why i said change the switch
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I know they fail, agreed.
But astra should be able to run miles before overheating at this time of year without any cooling fan required.
It's only really there for the superhot days or excessive traffic jams etc!
Take a good running astra, disconnect cooling fan an drive it to compare! It willbe ok. Hence why I suspect bigger cooling problem.
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thanks for help guys. il give the switch thing a go. what are signs of head gasket gone? water pump gone? thermostat?
thanks
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Classic head gasket signs include (but not exhaustively) lack of power, excess steam from exhaust, coolant in oil, oil in coolant, excessive water loss without explanation.
water pump is more unusual but normally car is ok in traffic jams, stationery but overheats rapidly when moving, but all parts of cooling system get hot etc.
Have experienced cheap chinese water pumps failing on vauxhalls!
Thermostat can fail open or closed. Open failed just takes longer for the engine to get hot and wont affect overheating. Failed closed and it stops water circulating to rad via top hose (generally but occasionally bottom hose). So engine will be hot, but hoses and rad will be cold.
Radiator problem is generally identified by excessive heat in 1 area and virtually cold in 1 or more areas, normaly close by.
hth
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Must eliminate head gasket before changing switches, thermostat, etc ...
If head gasket is gone the combustion gases have to enter the cooling system ...
It is not automatic that the water will get into the oil and vice versa ...
oil and water can be normal ... and head gasket can still be gone ...
Combustion gases entering the cooling system can effect the thermostat opening ... depending on where the thermostat is ... if air gets trapped under thermostat ... it will not open unless there is water at the correct temperature to open the thermostat ...
Take the cap off the expansion tank (not when hot) and fill tank to the brim with water ... let engine run without cap for 10 to 20 minutes ... if after this or sooner you see a steady stream of small bubbles ... or there is no bubbles for say 10 to 20 seconds then suddenly there is a large bubble ... then head gasket is gone ...
If there is no air bubbles ... Head gasket should be OK ...
Now check for restrictions in the water flow through the radiator ... is radiator partially choked ... is thermostat opening ... (thermostat is usually on the end of the head behind the t/belt on the Astra) ...
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