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Discussion Starter #1
I’ve just replaced the relay fuse and the therm switch fan in the radiator. Temp still reaching 175 quickly then within minutes close to 250 triggering red heat warning light on dash. Fans not turning on. Any ideas would be greatly appreciated
 

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86 Veloce
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Thermostat stuck closed?
 

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But Mad North-Northwest
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Thermostat may be stuck closed. Is your top radiator hose getting hot? If it's not you're not getting flow through the radiator and the fans won't trigger.
 

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Pop the thermostat out and test it in a pot of water, watch and see if the thermostat opens or if its just locked.
I like to watch the thermostat as the pot of water warms, rather than wait and see if it changed. You will be able to see the spring move
 

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Thank you for your replies. I’m a novice to this car can you suggest best way to remove thermostat. I don’t even know where it’s located exactly.
 

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Here you go, heres a pic of where the thermostat is located.
Unbolt the thermostat housing and pull the thermostat out.
Heres a video also on what to watch for when you test it with boiling water.
 

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But Mad North-Northwest
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This is a Motronic Spider, Aaron. Different layout and different thermostat than in that picture.
 

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Discussion Starter #9
Here you go, heres a pic of where the thermostat is located.
Unbolt the thermostat housing and pull the thermostat out.
Heres a video also on what to watch for when you test it with boiling water.
If I unbolt it do I need to drain the radiator fluid first since it’s attached to the upper hose ?
 

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I knew there would be a write up somewhere around here.
My bad, I did not realize the thermostat layout was much different between the series.
Nonetheless, testing the thermostat out of the car is no different @msena34

Instructions on what to do with the coolant are also in this write up.
 

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I’ve just replaced the relay fuse and the therm switch fan in the radiator
is there coolant in the radiator overflow bottle?

did you test the fans even work?
pull off the two connectors from that new therm switch, and with the ignition ON, simply join the two wires you just pulled off.....do the fans both work?
 

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Hi, when the thermostat is stuck it is probably stuck open. There is a fan sensor on the radiator that can fail, as well as the relay that controls the fan. I would also check if the waterpump is working.
All the best, Pim

Verstuurd vanaf mijn AGS2-W09 met Tapatalk
 

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Discussion Starter #13
Pop the thermostat out and test it in a pot of water, watch and see if the thermostat opens or if its just locked.
I like to watch the thermostat as the pot of water warms, rather than wait and see if it changed. You will be able to see the spring move
If it is stuck is it repairable or time to buy a new one?
 

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1987 Alfa Romeo Quadrifoglio
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When was the last time the coolant was flushed? You should also test the radiator for leaks.. but if it immediately jumps up to too hot, it's most likely a faulty thermostat. This would be a good time to flush everything, replace hoses if needed and check out the radiator.
 

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Discussion Starter #16
Thermostat may be stuck closed. Is your top radiator hose getting hot? If it's not you're not getting flow through the radiator and the fans won't trigger.
Top radiator hose is getting hot. Haven’t jumped the fan yet.
 

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Discussion Starter #17
is there coolant in the radiator overflow bottle?

did you test the fans even work?
pull off the two connectors from that new therm switch, and with the ignition ON, simply join the two wires you just pulled off.....do the fans both work?
Having a hard time touching them together since they are in plastic covers
 
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