Mechanics

RADIATOR FANS NOT WORKING AND ENGINE DIES AT STOPS.

2005 Pontiac Grand Prix • 6 cylinder 2WD Automatic • 97,000 miles

I Replaced the thermostat, coolant, coolant switch and upstream 02 sensor because I was getting maybe 13 mpg hwy. My radiator fans will not come on I noticed recently and engine gets hot, also will die after idling at a stop. Fuse, relays, motors for the fans are okay a mechanic, not sure what the prob is?
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Joshm432
March 24, 2011.



Check for applicable trouble codes, anything? What is the temp gage showing?


JDL
Mar 24, 2011.
I've got two new trouble codes 0053 and 0030. Since the repairs the engine temp gauge reflects that the temp needle is at 60% of total engine heat. Months ago, before repairs were needed it was 40% or below. I just had these above codes given to me and at the same time I had my alternator checked. The auto parts guy said it is okay. Then he checked the battery and said it's 50% and won't hold a charge, this is when the car has been off. Not sure if he's accurate.


Tiny
Joshm432
Mar 24, 2011.
I'd have top check actual engine temp in degrees. If those are P codes, it's for 02 heater circuit.

If the battery is down, we can't do any testing. You either have to get it charged or get a new battery. Does the starter crank ok? If you use a digital multimeter across battery posts, key and everything turned off, what is the reading?

With the work you've done on it, possible air in the cooling system?


JDL
Mar 24, 2011.
Wow, I just noticed I'm still getting about 12 or 13 mpg hwy on my grand prix, put in new engine air filter and full synthetic motor oil the other day I have to mention. Back to what we were talking about. It may be the 02 circuit, the battery isn't down completely. I think having this original battery though is the reason for engine to die at stops during idle. Starter turns the car over fine every time. As for the radiator fans not working its gotta be the wires from the fans, which I think is odd or the heater circuit which I could actually check real quick before even doing the temp gauge. So I think anyway? The fans not working do you think could be related at all to the battery supposively not hold it's charge?


Tiny
Joshm432
Mar 24, 2011.
With the engine running, the alternator should carry the load. Did you use jumpers to see if fan will run off the battery, for testing. You should use an inline fuse.

I'd have to check voltage and ground circuit at the fan relay/s.


JDL
Mar 25, 2011.
I checked the fuse for the SIR sensor or 02 sensor, the fans as well and none are broke and just bought 2 alligator lead lines. I don't have a voltmeter. Does it mean anything if I just started the car up, disconnected the negative battery wire and the car still runs? Can I somehow test to see if the relays are good although I don't have a voltmeter?


Tiny
Joshm432
Mar 25, 2011.
If taking the negative battery cable loose means anything, I don't know what? I wouldn't take anything loose with the engine running. Without a voltmeter or testlite, hard to do any testing.


JDL
Mar 26, 2011.
I found out that the Mass Air Flow sensor was bad, so I just had that replaced at a shop. They said the vehicle's computer though needs to be reprogrammed because that should fix the radiator fans. What's another name for the computer that controls the radiator fans? He also said (the mechanic) the car will still run pretty rough even though the MAF was replaced, but should help your 5mpg problem some. He referred me to the dealer for the computer issue. Because he said he can't reprogram the computer or replace it. I'm not sure if I should go to a dealer, I just called one and they want 130 dollars for one hour to look at it?


Tiny
Joshm432
Mar 28, 2011.
Pcm controls the fan relays. A lot of places will charge 100 bucks just for the diagnostics, even if they don't fix it.


JDL
Mar 28, 2011.