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Hey, new here! Got a few problems.

2K views 15 replies 8 participants last post by  JBert 
#1 ·
Hey everyone, checked this forum out a number of times in the past for car trouble help. But I've been having this ongoing problem that I can't seem to find a solution to.

I have a 2006 V6 Mustang. I've had a lot of problems with it blowing all of the coolant out quiet frequently. I feel like I've tried almost everything to fix it. So far I have replaced the thermostat, the hoses, the water pump, the cap twice, and the engine temp sensor. I've seen no indication of a leaking head gasket, as I haven't seen water in the oil or signs of leakage around the outside.

I've been trying to monitor the temps too and it seems like it blows out when I'm in slow traffic as the temps climb into the mid 210s. The fan doesn't kick on until like the late 210s and by then it doesn't help. I was running pure water for awhile because it was costing so much to buy antifreeze every week. But have been running antifreeze again and it still happens. I've tried making sure that I get the air out when filling it, but I don't have one of those special sets to do it properly.

Any ideas what I should try next? I may be forgetting some things I've tried, so I'll try and stay active here about it.
 
#2 ·
Your engine temps appear to be within the standard operating temps. Your radiator cap will release pressure in the cooling system up to about 18 psi. You may have a head gasket leaking pressure into the cooling system. There was an chemical that you could put in the radiator to test for combustion gases but I don't remember what it was. You might have to take it into a shop to have them test for excessive pressure in your cooling system.
 
#3 ·
So I just did another test, drove around till it was warmed up and then parked and let it idle. It climbed to 226 degrees and then boiled over. The fan never kicked on. I know the fan works because when I turn on the AC it kicks on and off and if I disconnect the Engine Temp Sensor it runs constant.

I seem to recall reading the fan should come on when the temp reachs 219 I think. Does anyone know why the fan wouldn't be coming on? If I had a bad relay, the fan wouldn't come on at all, right?
 
#7 ·
hmmmm, I think you are on the right track but I'm not sure how to sort it out . . . pretty sure there are some threads with the details you are looking for, in the GT Tech or General Discussion sections

I think you are right, if the fan comes on with the A/C then the relay is good; so there is some other reason that the fan is not coming on. Yes might be the sensor but I think there could be other things, which are detailed in the other threads, hope you can find them
 
#8 ·
Yeah, I'm checking the fan connectors now to see if they are bad. The 40 Amp fuse in the engine fuse box looks good. I'm gonna get a multimeter later and start testing the electronics.

I was reading about some people saying their connectors were melting together. I'm checking the connector by the fan, there is a resistor housed in the fan, and it looks like the connectors are stuck together there, although I'm not sure if that's by design or not.
 
#9 ·
This sounds like the issue, this resistor allows the fan to run the multiple speeds. The systems is designed to turn the fan on high speed when the A/C is turned on because that's a heavy load on the engine making it run hotter.

Resistor - Ford (7R3Z-8L603-A)
 
#14 ·
Yeah, that was through Ford. None of the local autoshops even knew what I was talking about. I did end up ordering one online for a little cheaper.

Yeah, I'm aware of the high and low relays. I've tested them and they both work. We also tested the connection between the relays and the resistor. The resistor by the way is on the fan housing. We are getting nkthing through the low speed part so I think it may be broken off. That's why my high speed fan works but not my low speed fan.
 
#16 ·
cool, thanks for closing the loop with us!
 
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