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Discussion Starter · #1 ·
I have a 2005 407SW 2litre that has been overheating when stuck in traffic on very hot days and I'm not convinced that the cooling fan is operating. I would expect it to come on once the water temp got above 90 and stay on after I switch off until it cools down but I can't hear it so I don't think its working.
How best can I test
a) the fan itself
b) the thermostat that controls it
c) anything else that might be stopping it
Many thanks
Joe
 

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Best test is to get it on planet and do an actuator test. On most models if you disconnect the coolant sensor the ecu/bsi will fail to safe and fun fan constantly.

Not sure on a 407 but on 307 there is a relay unit on rad pack which corrodes and stops fans running on slow or fast speed or both
 

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Discussion Starter · #3 ·
Best test is to get it on planet and do an actuator test. On most models if you disconnect the coolant sensor the ecu/bsi will fail to safe and fun fan constantly.

Not sure on a 407 but on 307 there is a relay unit on rad pack which corrodes and stops fans running on slow or fast speed or both
Thanks windy, that's helpful.
I've now discovered the fan does run when it gets hot (it's been a nice day here) but stops when I switch off. Other cars I've had (BMW) keep the fan running even after switch-off until they cool down and I was expecting that to happen with the 407.
Am I expecting too much?
 

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I have not known fan to over run unless its a diesel after a regen or with a failed temp sensor.

Does slow speed fan work, most are two speed low speed from around 3/4 on gauge and full speed when it hits the red
 

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Discussion Starter · #5 ·
Slow speed fan working ok but my real problem is that the engine won't restart when it's very hot ie over half way up the guages.
It has been suggested that it might be a faulty crankshaft sensor. Is there anyway to test this?
 

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RHR RHK type engines are not prone to overheating so although you now say your fans work you do have some form of issue the hot starting issue could also be a weak starter these get slower when too hot.

The heat needs further investigation its not simply lack of fans as in normal use the fans will rarely come on something is causing it to get hot.
 

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Start a new thread and give us more information....like engine type..year model
 
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