2001 fordpickup false overheat faults

I have a 2001 f-150 which I bought new, and love. I have had no trouble with it until recently. It gives a false over heat reading, I know this because I've had my shop put the heat gun on it and it is running at 230degrees which is normal, but the gage reads into the red which will tell the computor to kill the a/c, etc. After turning off the truck for only a couple of minutes, it can then be re-started with the gage returning to the correct reading, which is about half way on the gage. It will do this with the a/c on or off. I have had the cooling system flushed with the BG chemicals, and have had the thermostat replaced. Also the sending unit has been replaced. The plugs have also been changed, all of this was done after the problem started but, with 72,000 miles I thought it was time for the extra stuff to be done anyway. Without having an endless supply of dollars to just keep replacing parts, I sure would apprciate any input from someone that has already been through this and could solve the problem. Thanks in advance for any help!

How about the Coolant Temperature Sensor?
I am not certain what you mean by the sending unit. IIRC, Ford uses 2 sensors. One for the tamp gauge, and one for the computer's readings.

What codes is the Computer throwing?

Nope, the CTS IS EECs temp sensor, it is also called the ECT sensor. Most '98-current engines also have a CHT (Cylinder Head Temp) sensor that is dry. The ONLY use for this sensor is for operation under low coolant conditions when the enigne is operating a 1/2 power firing every other cylinder (1/2 cool, 1/2 provide power).

If it's running 230*F, that is NOT "NORMAL", not even close. The factory stats are 192*F-197*F and "normal" operating temps range from 190*F-210*F. If you are above 210, it's overheating.

The mod dude could be right. The only reason I thought of the 2 temp sensors is because my SC has them. One for the gause, and one for the EEC.

But this guy works on the damned things, so I'd go with what he says.

Thanks for the info. My truck is one of the few that only has one temp sending unit located at the bottom rear of the engine. The location for the head sensor has a factory plug in it. The shop where I took it may have actually put in a thermostat rated too high which I think would let the truck over heat according to what the sensor and computor would be set for. If the thermostat is the wrong one, I guess I'll just have to nail them on it and get them to correct it with the right one. I was there when they put the heat gun on it and it was a definate 230 which they said was normal. I'll definately follow up on this and let you guys know what happens from here. This will definately be another learning experience as far as asking the right questions. The guys actually did sit with me and go through senarios of what could be causing the problem but, I never thought of a wrong range thermostat. This would be a good lesson for them as well. Thanks again and I'll let you know in a few days whats up.

There is no temp sensor at the "bottom rear" of the enigne, that would be a KNOCK sensor. The ECT sensors are ALL in the coolant crossover near the coolant ports in the heads at the front top of the engine (where the coolant is the hottest).

As for the wrong thermostat, the highest temp stat made is a 197*F unit. However, there have been reports of people putting non-correct stats in (like for a 5.slow) that a) CANNOT work porperly and b) are of a higher rating than you can get in the correctly designed stats.

BTW, I know the production manager for the firm that makes the stats for Ford, get ONLY a FORD/Motorcraft stat there IS a very significant difference in performance, tolerance, and overall quality between brands. They are NOT "all the same", not even close.

The latest is that the thermostat installed was a 192*. The mech I use said that Ford told him that with the correct thermo the truck "operating" temp can still be in the range of 190-230 even though 230 would be on the high side that it still would be in the range and should not cause this problem. I do not know for sure that he used a Ford spec thermo, but I did see a dealer truck deliver the part. I will check to make sure. As for the sending unit, I was there when they looked on the computor service disk and it showed a sensor where mine is plugged but, the only other place it showed was on the drivers side bottom rear, and I watched as they changed the unit. I'm certainly confused about that. If it was not the sending unit, what did they change. I will follow up and thanks again for helping a pre-computor points and plugs guy.

230*F is at the VERY TOP of "normal", and something you'd ONLY expect while towing with the A/C on during very hot weather.

Since I work mostly on our diesels, I'll have to look at one of the late model gas enignes, but from memory, ALL the ECT sensors are located at the top front of the enigne in the coolant crossover.

Well, still no news on my end of this thing except that I still have the problem. I can drive as little as 15 minutes before it shows into the red, or it can take as long as 30 minutes before it starts to read hot. It really makes no sense because I can shut off the engine for as little as 2-3 minutes, then start it again with the gage reading back in the range which used to be normal for my truck (mid gage). Is there a trouble shooting procedure or matrix that is followed at Ford shops for a problem like this, such as first check the thermostat, then check the fan, then the water pump, etc. Or is it usually up to the discretion of the mechanic assigned to the vehicle? Also, has there been cases like this where it has been due to a wire connection being loose or just bad? It just seems like if it were really that hot that it would take longer to return to a normal reading than 2-3 minutes. Are there any "good" manuals out there that show how the cooling system actually is designed to work?

Info from another web site is that it is the radiator. At least 3 other individuals have had similar simptoms and all were cured when the rad was replaced with a new one. Two of them even had the old rads boiled out at a rad shop with the problem reaccurring within a couple days. Both also have not had any problem since replacing with a new one. Since I have had my system flushed with the BG system, and was told that it flushed clean, I did not think the radiator could be the problem but, these other cases had been told they had clean rads as well. Even though this makes no sense, is there any info that you know of to support this coarse of action?

Based upon what's already been tried, I think a radiator is a good bet if nothing else.

The other guy's who replaced their radiator said they paid under two hundred dollars for new ones. Based on what you said about using factory spec thermostats, I have not found one under $260 from local (Oklahoma) parts suppliers. I have not even priced a dealer yet. Am I missing something, or are they just less expensive other places? By the way- thanks again for all the input!

Well there are radiators, and good radiators. Check www.motorcraft.com, and you local dealers/parts houses. My only advice is to get one made in the USA. If the prices are all over $200, just check on getting yours "recored". Basically, they only re-use the tanks, so it is "new".

Okay, so my brother in laws Expidition is overheating but only after traffic situations in high heat with the AC on. The Fan clutch was faulty and the coolant was nasty so I replaced both along with a new thermostat and in did'nt overheat for a few days but now it's happening again. There are no signs of headgasket failure (blue smoke, oil in coolant, etc) and no loss of coolant from the lines or cap. If it were the water pump it would purge right? I am stumped, any help would be appreciated. Keep in mind that I know imports like the back of my hand but this is the first ford I have wokrd on besides my best friends 02' stang GT.