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More cooling fans and temp issue at speed

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Old 06-03-2018, 04:02 AM
  #46  
Speedtoys
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Ya got one of these?

Old 06-03-2018, 10:14 PM
  #47  
dr bob
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There’s a switch on top of the intake that is one of only two possible causes of S4+ fans running after engine stop. The other is a similar temp switch on the auto gearbox.

The fans run based on coolant temp sensor in the radiator outlet side tank. They also use the system pressure in the HVAC system.
Old 06-04-2018, 07:25 AM
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vsalvato
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Originally Posted by dr bob
There’s a switch on top of the intake that is one of only two possible causes of S4+ fans running after engine stop. The other is a similar temp switch on the auto gearbox.

The fans run based on coolant temp sensor in the radiator outlet side tank. They also use the system pressure in the HVAC system.
Dr Bob, thanks for the hint. So having the fans running for several minutes after the engine is off is definitely not normal? So what about the two switches, and the fans running after engine switch off; would it mean that either one of the switches does not work properly or would it hint to a deeper problem? What would you recommend to check?
Old 06-04-2018, 08:35 PM
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Running for a few minutes after engine stop is nothing to worry about. Much more than that deserves a look. Check the trans fluid and fluid level too, as that’s the only other tem that runs the fans after engine stop.
Old 06-05-2018, 04:26 PM
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Originally Posted by dr bob
Running for a few minutes after engine stop is nothing to worry about. Much more than that deserves a look. Check the trans fluid and fluid level too, as that’s the only other tem that runs the fans after engine stop.
Thanks! Will definitely check coolant and trans fluid levels prior to dig deeper into any other matter
Old 06-05-2018, 05:46 PM
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Originally Posted by vsalvato
Thanks! Will definitely check coolant and trans fluid levels prior to dig deeper into any other matter
back to if a problem actually exists...

What are your actual temperatures at the rad hoses, the thermostat...?

Do you own a temperature gun?
Old 06-06-2018, 02:46 AM
  #52  
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FWIW, I had to replace the intake switch a week or three after an engine bay clean and detail. Apparently the switch doesn’t like to get wet. Even in the dry desert climat above Los Angeles, the corrosion devils ate the switch guts.

Disconnect the brown ground round wire on the switch after checking the intake temp with the IR temp gun immediately after engine stop, while fans are/were running. The hood switch should stop the fans, so you may need to secure that for functional testing.



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