Cooling system issues?

[07silvergt]

On an 07 gt what controls the radiator fan? A sensor and a relay? The pcm? Does the AC system also? I do think they use the same fan right?

The reason I ask is that 2 days ago the car started overheating. No loss of coolant, no hose issues etc. It was diagnosed as the cooling fan not running. (Although I know that fan would still come on sometimes because when it did the temp came down fine and I visually saw it running)
Anyway, the fan was replaced and it was fine all day (I'm going across the country) until I came into Chicago and it overheated again. I checked and the fan was not on. It did come back on because the temp went back to normal and it was good for another hour. It started overheating two more times later.
Any idea what's going on here?

 

[86GT351]

Was the Fan Plug replaced also? Common issue for them to burn back into the plug and harness.

 

[07silvergt]

It doesn't look like it was replaced. I was also thinking the relays in the fuse box. There's a high speed one and a low speed one. I got a ford dealer in chicago looking at it now.

 

[07silvergt]

Nitro, you were exactly right. It was that the plug was burnt.

 

[86GT351]

Nitro, you were exactly right. It was that the plug was burnt.

Very common issue. Have experienced it myself!

 

[Newman]

Mine did it back in 2010, just hard wired it on all the time .

 

[petersonb]

Bumping an older thread here....

Where does this plug burn? I checked the plug which goes right into the fan motor, no burning/melting there... And then the next place the wires go is a rectangular plug, which I didn't disconnect (not trying to work on the car too much on game day).

My car is overheating all of the time, highway and city, and the relays and fuses are all good. The fan turns on high and low when I put power directly to the relays to trip them, so fan motor works as far as I can tell.

Is there a PID for fan, so I can see, while driving, if the fan is on?

Thermostat affects the fan? I thought thermostat opens to allow coolant flow... Tune is set for high speed to kick in at 228, but car was at 238 when I noticed the gauge was tipped towards H .... If I turn on the heater full blast in 85-90 F weather, coolant temp stays around 200-210, but as soon as I turn it off, or turn on the A/C (which is still cold), it climbs above 230 pretty quickly.

Can an alternator cause something weird? I might have a bad alt..

 

[petersonb]

Bumping an older thread here....

Where does this plug burn? I checked the plug which goes right into the fan motor, no burning/melting there... And then the next place the wires go is a rectangular plug, which I didn't disconnect (not trying to work on the car too much on game day).

My car is overheating all of the time, highway and city, and the relays and fuses are all good. The fan turns on high and low when I put power directly to the relays to trip them, so fan motor works as far as I can tell.

Is there a PID for fan, so I can see, while driving, if the fan is on?

Thermostat affects the fan? I thought thermostat opens to allow coolant flow... Tune is set for high speed to kick in at 228, but car was at 238 when I noticed the gauge was tipped towards H .... If I turn on the heater full blast in 85-90 F weather, coolant temp stays around 200-210, but as soon as I turn it off, or turn on the A/C (which is still cold), it climbs above 230 pretty quickly.

Can an alternator cause something weird? I might have a bad alt..

I adjusted the tune to call for high speed to kick in at 210, I datalogged and it shows that the fan was called to turn on right at 210, but then the ect continued to climb to 218 before I got back in the driveway and shut the car off.

My tune is calling for 14.3v, but vpwr is showing 13.8-14.0v, so my "CHECK CHARGING SYSTEM" message is showing up.

Can these two somehow be related?

Coolant system and fan wiring stuff all look okay, at quick glance.

Ideas?

Thanks,
Brad

 

[86GT351]

Sounds like you have a bad Coolant Temp Sensor. If mechanically everything else is working then that is the issue. Fan turns on with direct power. With you modifying the control of the fans in the tune, the signal is still referenced through the CTS. CTS no good, fans don't turn on!

Do you have a scan tool that shows live data? Not through your data logger.

 

[petersonb]

Sounds like you have a bad Coolant Temp Sensor. If mechanically everything else is working then that is the issue. Fan turns on with direct power. With you modifying the control of the fans in the tune, the signal is still referenced through the CTS. CTS no good, fans don't turn on!

Do you have a scan tool that shows live data? Not through your data logger.

Bear with me here....

So, with a bad CTS, fan can be turned on with direct power.....

But would that mean the temp shown through the OBDII is incorrect? Or does that value come from some other sensor?

My datalogger is showing that Hi-Speed fan is being turned on at 210*..... So a bad CTS would be trying to output that signal?

In other words, a bad CTS means a disconnect.... where? At any rate, I will look into getting a new CTS from Autozone

 

[86GT351]

The CTS sends a signal to the PCM based on Temp and Resistance. The PCM with a pre set or your custom tune is supposed to send a signal out to the relay to turn the fan on at the desired temp. If you are saying based on tests that the fans work if you power them up and the relays are working then it has to be the CTS. The Temp should be correct. The Sensor is just not sending the signal at the desired temp.

http://en.wikipedia.org/wiki/Engine_coolant_temperature_sensor

 

[petersonb]

The CTS sends a signal to the PCM based on Temp and Resistance. The PCM with a pre set or your custom tune is supposed to send a signal out to the relay to turn the fan on at the desired temp. If you are saying based on tests that the fans work if you power them up and the relays are working then it has to be the CTS. The Temp should be correct. The Sensor is just not sending the signal at the desired temp.

http://en.wikipedia.org/wiki/Engine_coolant_temperature_sensor

I think the CTS is sending the signal, because the datalogger shows 0 and 1 for "On'' and "Off" on "Low Speed" and "High Speed"

As soon as ECT hits 210, the hi speed fan signal changes from 0 to 1

 

[bjtheman1]

I recently went through the same annoying over heating issues.

Here was the culprit!

 

[TexasBlownV8]

there is no coolant temp sensor on a 4.6. coolant temp is inferred from ect.

yes there's low and high speed fan signals, and you can actually see them switched on or off from the voltage on the 2 wires from the pcm to the bec.

The pcm controls those two and triggers one of the relays by grounding the coil side of the appropriate relay, energizing it. Its up to the wiring to deliver the current to the fan. Its very common also for the connector under the bec to get burnt.

 

[petersonb]

I think all my sensors and stuff are okay.

I think the problem is air in the system. I've spent all afternoon researching these fill techniques, but I can't find any of the bleed valves or anything that anyone's talking about. I'm thinking this Dept of Boost manifold setup has removed that...?

 

[86GT351]

there is no coolant temp sensor on a 4.6. coolant temp is inferred from ect.

yes there's low and high speed fan signals, and you can actually see them switched on or off from the voltage on the 2 wires from the pcm to the bec.

The pcm controls those two and triggers one of the relays by grounding the coil side of the appropriate relay, energizing it. Its up to the wiring to deliver the current to the fan. Its very common also for the connector under the bec to get burnt.

You are correct. Here is a good write up I found about the Cylinder Head Temp Sensor!

http://www.allfordmustangs.com/foru...ech/121152-there-no-water-temp-sensor-gt.html

 

[86GT351]

I think all my sensors and stuff are okay.

I think the problem is air in the system. I've spent all afternoon researching these fill techniques, but I can't find any of the bleed valves or anything that anyone's talking about. I'm thinking this Dept of Boost manifold setup has removed that...?

Ford actually suggests the usage of a Coolant System Vaccum system to properly bleed the system through the coolant tank.

 

[kell0177]

Did you check to see if you have good flow through the radiator? Possibly a clogged radiator? Otherwise I'd say your thought of thermostat is most likely right.

 

[G.T]

disconnect your battery, pull up the BEC (fuse box) cover, remove the main power supply (size 10mm) and remove the 7mm bolts holding up the connectors.

take out the fuse box, and look at all the plugs underneath.. i'm willing to bet your low speed and/or high speed contacts are all burnt up

 

[petersonb]

Thanks for the input guys!

Which way does the coolant flow? The GT450 manifold moves the neck to the passenger side, and straight into the top of the radiator, also on passengers side.

The driver side has the hose on the bottom of the radiator to a T connector, which connects to the bottom driver side of the block, and the hose to the degas bottle.

My 2006 Mustang has 2007+ hoses as part of the gt450 setup. Thermostat is still in its original place, but the neck has moved to the passenger side