johngt10

Ok mods should be in my Sig. June 7th my car would start overheating in traffic or anytime i was under 40mph and the air conditioning would stop working due to no air moving through the condenser. Got home ans found the cooling fan wasn't coming on even when the ac was turned on. June 15th I replaced the cooling fan, resistor and the connection from the wiring harness were replaced due to the connections melting. Fan worked the way it should. Today 07/02/12 it is doing the same thing. I took it apart again and checked the connections and they we're fine. I had a coolant service performed Friday last week. After I put it back together I started it back up and the fan worked.

Now before everyone suggest its the thermostat let me explain how it works. The thermostat opens when it reaches a temperature and cooled off coolant from the radiator flows into the block.

Now what happens if your sitting still and the cooling fan is not running when it needs to be? The already hot coolant that wasn't cooled off flows into the block causing it to overheat.

So it is NOT the thermostat. Sorry I already had too many fb friends try to say that. This issue is something with the fan. It just doesn't work when it needs too. The motor is fine and so is the resistor. I was told it may be a temperature sensor for the fan that is bad. Also I was wondering if maybe it might be a setting in my tune from bama.

Also a little fact. My car has the same setup as the 05 model gt's and up.

Any help would be appreciated.

hammeron

at this point i would want to check the Cylinder Head Temperature sensor or it's wiring, seems like you have covered everything else.

i think that the CHT sensor is what the PCM uses to determine when to turn on the low speed and high speed fans (based on the tune's values of course).

good luck and i hope you get it sorted out soon.

moosestang

I agree. My fan comes on at 220 and slowly drops to 215/210 or 205 before it shuts back off. This car doesn't even have a coolant temp sensor, it use the head temp sensors to determine the coolant temp.

There is only 1 CHT sensor, I think, and it's under the intake manifold in the passenger side cylinder head. You can see it in step 50 of the whipple manual and they show the connector on the firewall in step 52.

http://home.comcast.net/~cookpaging/...ls/whipple.pdf

Do you have a scan tool that will show the head temp sensor reading?

AMDanBailer

johngt10,

I am sorry to hear about the overheating issue you are experiencing. When it comes to the tune, the only part of the file related to the coolant temp is what temp the fans turn on. In all tunes they are preset to turn on 5* lower then your factory setting. Since this issue went away & came back, I don't believe its related to the tune at all.

It sounds like the head Temp sensor in the cylinder head may be acting up(since you replaced everything else) that may be your only other option at this point.(this is the sensor that measures the coolant temp)

I agree with the above post, get your hands on a scanner that can read your coolant sensor & see exactly what its doing.

If it would give you closure on eliminating options, you can have my Bama team open your file just to go over everything ( I am confident its not related). Our Bama Performance tuning specialists are here in the building Monday-Friday from 9AM-5:30PM EST and Saturday 10AM-3PM EST. You can hit them up directly at 888.226.9764 and they'll get you squared away!

I hope this helps!

- Dan

Derf00

The little fact is not entirely accurate. 05 to mid 06 have one style of cooling system, late 06 and on have a different cooling system. The difference is in the placement of the thermostat. Early models have it in th Lower hose assembly. Ford found this to be inefficient and moved it to where it sits now (under/behind) the alternator)

A sticking thermostat could cause that issue (not the fan one). Have you stuck your thermostat in boiling water to make certain it opens 100% or did you replace it?

Did you find the source of why the Fan wiring harness melted in the first place? Shorted somewhere?

moosestang

Well it's not the thermostat. If it were, then it would overheat at any speed.

I would replace the head temp sensor first, if it's cheap, or check the pin from the ecm that controls the fan, make sure it's getting power when the temp reaches 215 or 220.

Derf00

Automatically ruling out the thermostat is a mistake, unless it's been tested or it's a new one. I've seen it happen before. They can hang but whatever, I'm curious to see what the solution turns out to be.

johngt10

I've had to deal with thermostats sticking before. Like moose said if it was sticking I would have issues at any speed ans that's not the case. That sensor sounds like it will be my next move. The shop I had install the headers will be taking a look at it thursday morning so hopefully it gets resolved. If its not the sensor then it might be a short somewhere. One thing that I also noticed was yesterday it rained and i drove about 5 miles in the rain and noticed it overheating and pulled over to find the fan not running. The first day this happened before I took any action it was raining as well. I only assumed the 05 and up were the same due to the parts I needed to replace the fan and resistor came from an 08 gt and the connector on the wiring harness that was melted I got off of a 2005 v6.

Also I had a buddy call me that has the same mods as me minus different brand headers. He said his car did the same thing and he had the dealer look at it. They replaced the fan motor, resistor, and connector to the harness. It melted again so then the dealer replaced the entire engine harness. His was covered under the drivetrain warranty. I spoke with the same dealer he used and since my warranty ran out 10,000 miles ago. Anyway he gave me a quote for labor and parts for $2,200. Not worth that to me so I'm hoping we figure it out Thursday.

Throck!

The fact it only happens under 40 mph makes me think you may not have enough air flow through the radiator.

Mine was heating up and creating a smell that I think is the A/C coolant venting. The power steering fluid also burned and the steering stopped working.

I have the edelbrock e-force with a heat exchanger the size of the radiator. I wondered if the heat exchanger was creating enough air flow resistance that not enough air was flowing through the condenser, the steering cooler thing or the radiator.

I ended up putting the biggest fan i could find on the front of the heat exchanger. I think it might have been this one:
http://www.zirgo.com/catalog/Cooling...Fans/ZFB16S/16

Anyway, it hasn't overheated again...but I haven't driven it through 100+ temps since either.

If you get a fan, make sure it blows the right way or is reversible.

Also, when you top off your radiator, make sure you're using deionized water, not tap water. The hardness (carbonates/bicarbonates) in tap water forms a white scale on surfaces when it's heated (like in boilers/hot water heaters/engines). This scale is an insulator, meaning the system won't cool as efficiently.

johngt10

.... That's right. Did you not see that I said the fan is NOT working? This would cause exactly what you said which is what's happening.

Not being smart, i just know I posted a lot so maybe you didn't see me say that.