1989 cooling fan
Thread Starter
Instructor
Joined: Apr 2007
Posts: 155
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From: Fern Creek Kentucky
1989 cooling fan
At what temp should my electric fan come on? I have a stock '89 L98 automatic and it seems to be running hot. The fan will come on if the a/c is on but will go off when I turn off the a/c.
Le Mans Master
Joined: Aug 2000
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From: Australia
Le Mans Master
Joined: Dec 2000
Posts: 7,839
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From: San Diego, Ca
Except the '89 specs (non a/c) are 226 for the Main; 228 for the Aux. Main is driven by the ECM with input from the Coolant Temp Sensor; so if you want to see what that is, you'll need a Scanner. The Dash Gage gets it's input from a Thermistor screwed into the right head and can show a temp differential of a couple degrees. Aux is from a switch in the left head. Aux should rarely if ever come on. Check it by blocking air flow - or if it is coming on, that's a good indication of a cooling problem. With a/c, Main is driven by the ECM (regardless of Coolant Temp) when a switch on the High Side opens at around 220 psi. You'll need a Manifold Gage Set to check it.
