2000 Malibu cooling fan won'T turn on

simlarock · 08-02-2008, 10:29 AM

Hi.

I've Been having problem with my 3.1L, overheating. The cooling fan isn't coming on but if I disconnect the sensor it will the temp gauge will come down and the car won't overheat, howerver the check engine light will come on and the transmission will engage really hard. My mechanic replaced the coolant, rad cap, thermostat, temp sensor and fan still not coming on engine still overheating?!

Your help would be greatly appreciated.

Thanks

**Midnight Tech** · 08-02-2008, 12:46 PM

Check the cooling fan relay - sounds like it's not working.

jimmy917 · 08-06-2008, 06:35 PM

If the fan comes on when you disconnect the sensor, then you know the relay works. You have a command problem. To diagnose this correctly, you need to have a scan tool plugged in, and see when the temp climbs high enough, if the PCM requests the fan to come on. If the request is there, but command never happens, then you have a bad PCM. Another thing to watch is for a blown head gasket. Coolant sensors cannot read correctly if there is air in the system. A blown head hasket will pump air into the cooling system, causing erratic gauge readings, and eventually overheat.

08-02-2008, 10:29 AM	#1 (permalink)
simlarock Registered User Join Date: Aug 2008 Posts: 1 OS: XP	2000 Malibu cooling fan won'T turn on Hi. I've Been having problem with my 3.1L, overheating. The cooling fan isn't coming on but if I disconnect the sensor it will the temp gauge will come down and the car won't overheat, howerver the check engine light will come on and the transmission will engage really hard. My mechanic replaced the coolant, rad cap, thermostat, temp sensor and fan still not coming on engine still overheating?! Your help would be greatly appreciated. Thanks

08-02-2008, 12:46 PM	#2 (permalink)
Midnight Tech Admin/Head GreaseMonkey/Igor's alter ego/Grand Exalted PoohBah Join Date: Dec 2001 Location: SC Posts: 2,928 OS: Windows XP Home/Pro SP3/Windows 98SE/Fedora Core 6/RH 7.2 with Autopoint/TAMS II	Re: 2000 Malibu cooling fan won'T turn on Check the cooling fan relay - sounds like it's not working. __________________ Please post all questions in the appropriate forum. Questions sent by email or PM will not be answered. Sharing my life...with my Imzadi! Interested in Trek gaming? Check out the Dynaverse! Proud supporter of the Carolinas Aviation Museum. If we have helped you in any way, please donate to keep TSF up and running!

08-06-2008, 06:35 PM	#3 (permalink)
jimmy917 Registered User Join Date: Aug 2008 Posts: 2 OS: XP pro	Re: 2000 Malibu cooling fan won'T turn on If the fan comes on when you disconnect the sensor, then you know the relay works. You have a command problem. To diagnose this correctly, you need to have a scan tool plugged in, and see when the temp climbs high enough, if the PCM requests the fan to come on. If the request is there, but command never happens, then you have a bad PCM. Another thing to watch is for a blown head gasket. Coolant sensors cannot read correctly if there is air in the system. A blown head hasket will pump air into the cooling system, causing erratic gauge readings, and eventually overheat.