Helpp Starts to overheat when i turn A/C on

[Ford4life32]

Was sitting in drive thru with A/C on, heard a pop then started steaming from under the hood pulled off to the side look at my temperature gauge was all the way hot. Opened the hood and the radiator reservoir cap had popped off and was boiling and sprayed coolant all over my engine bay. let it cool down poured some more coolant in and didn't over heat again.My coolant looked dirty as hell So that day after work i got my coolant flushed hoping that the thermostat just got blocked with some gunk or something. Then today at work i was sitting parked with the A/C on and i caught it just before it over heated. Kinda baffled on what it could be, the thermostat housing was just replaced within the last six months. Any suggestions would be great. :scratch:

 

[pzy3339]

sounds like the fan is not kicking on.

 

[Ford4life32]

soo yea...

So i took it to our mechanic, he had it running in the shop for 45 min with A/C on high and a computer hooked up the whole time the temp never changed and never over heated... he said it could be the fan clutch sometimes turning on and sometimes not. He didn't replace it only because he didn't know for sure if the fan clutch was bad, also because it was a $400+ job. So now i just wait and see if it ever happens again

 

[Ford4life32]

Its not just when i turn A/C on. went out on the trails with it after about an hour it started to over heat. I thought it was just when the ac was on but apparently not guess ill just start replacing things until its fixed then haha

 

[tripplec]

Well if you see the temp rising. Pop the hood and see if the clutch fan is turning at a good speed. Even check when it normal so you have a point of reference as to how fast its spinning.

On another note Gauges are put in for a reason. I look at mine often while driving and when come to a stop. I hate idiot lights as most come on when its too late in many cases and damage is done. Especially if not responded to immediately. They're a reason why they're called what they are since most people have no clue what each light means anyway and ignore them. LOL

A cooling system with the right coolant for the design does not get dirty, rusty etc. but changed now and then to keep the inhibitors which deplete over time back to acceptable levels in the system. Mostly water in the system is very bad on so many levels.

If you had work done before then an air pocket/vapour block might be a problem and requires burping to get out. Various techniques exist and some engines have bleeder plug for that reason.

If you get cleaning flush and refill done be 200% certain the correct Ford type of antifreeze is used. There are at least 3 types on the market that I can think off. The wrong once will take out the engine, rad and other parts quickly. The owners manual is your guide and/or the Ford service dept if in doubt. Don't guess on this and the green glycol type is not used on the majority of vehicles anymore nor Dexcool as I understand. Hoat type is much more common. Don't use a universal type like what Prestone make for example either. Get it right the first time or buy a new truck.

 

[Ford4life32]

Well if you see the temp rising. Pop the hood and see if the clutch fan is turning at a good speed. Even check when it normal so you have a point of reference as to how fast its spinning.

On another note Gauges are put in for a reason. I look at mine often while driving and when come to a stop. I hate idiot lights as most come on when its too late in many cases and damage is done. Especially if not responded to immediately. They're a reason why they're called what they are since most people have no clue what each light means anyway and ignore them. LOL

A cooling system with the right coolant for the design does not get dirty, rusty etc. but changed now and then to keep the inhibitors which deplete over time back to acceptable levels in the system. Mostly water in the system is very bad on so many levels.

If you had work done before then an air pocket/vapour block might be a problem and requires burping to get out. Various techniques exist and some engines have bleeder plug for that reason.

If you get cleaning flush and refill done be 200% certain the correct Ford type of antifreeze is used. There are at least 3 types on the market that I can think off. The wrong once will take out the engine, rad and other parts quickly. The owners manual is your guide and/or the Ford service dept if in doubt. Don't guess on this and the green glycol type is not used on the majority of vehicles anymore nor Dexcool as I understand. Hoat type is much more common. Don't use a universal type like what Prestone make for example either. Get it right the first time or buy a new truck.

When i was on the trails i had a little concern in the back of my head that it could possibly overheat so i was watching the temp gauge. Once i saw it going up i found a spot to pull over and shut the truck off to let it cool down. I have a feeling that it is the fan clutch. When i first got the vehicle sometimes when the truck got too hot obviously i heard the fan kick on causing a roaring noise when accelerating and after a while it would stop (got back to norm temp) and now it doesn't happen at all so i think im going to get the fan clutch replaced.

 

[Flag Gibby]

Just my two cents, but if you have not changed the thermostat spend the $30 on changing it before you spend the $150 or so on a new electronic viscous fan clutch. A sticky/failing open thermostat can cause the issues you are having. If you hear the fan running and changing speeds as the engine gets too hot then most likely there is nothing wrong with the fan clutch and typically when the electronic clutches go bad they send a trouble code.

 

[Ford4life32]

Just my two cents, but if you have not changed the thermostat spend the $30 on changing it before you spend the $150 or so on a new electronic viscous fan clutch. A sticky/failing open thermostat can cause the issues you are having. If you hear the fan running and changing speeds as the engine gets too hot then most likely there is nothing wrong with the fan clutch and typically when the electronic clutches go bad they send a trouble code.

Well in the past 8 months (i cant remember exactly) The thermostat housing started to leak so i had it replaced. So Im guessing that the thermostat was replaced???Or do you think that he used the same one? And i used to be able to hear the fan run and change speeds but not anymore. Thats why i thought it was the clutch. but since i havent gotten a code then i dont know then

 

[Flag Gibby]

Well in the past 8 months (i cant remember exactly) The thermostat housing started to leak so i had it replaced. So Im guessing that the thermostat was replaced???Or do you think that he used the same one? And i used to be able to hear the fan run and change speeds but not anymore. Thats why i thought it was the clutch. but since i havent gotten a code then i dont know then

Unless you specifically asked the shop to replace the thermostat the same one is most likely still in it. They would have used the same thermostat but used a new o-ring when changing out the housing. If you still have the repair invoice they would have line itemed what new parts were used during the repair and you would be able to tell that way if it was replaced.
The other thing to remember is that the OEM thermostat design is to fail open (if it is still the OEM style thermostat), so it could be that the thermostat is now failing completely open after getting stuck and keeping the engine from getting way too hot so the fan doesn't go into high RPM mode, or it could be that you are paying much more attention to it and turning the vehicle off before it even gets hot enough for the fan to kick on high.
I guess the question is, does the fan kick on when you first start the engine up and then come down in speed/sound? If it does then the fan is most likely functioning just fine.

 

[Ford4life32]

Unless you specifically asked the shop to replace the thermostat the same one is most likely still in it. They would have used the same thermostat but used a new o-ring when changing out the housing. If you still have the repair invoice they would have line itemed what new parts were used during the repair and you would be able to tell that way if it was replaced.
The other thing to remember is that the OEM thermostat design is to fail open (if it is still the OEM style thermostat), so it could be that the thermostat is now failing completely open after getting stuck and keeping the engine from getting way too hot so the fan doesn't go into high RPM mode, or it could be that you are paying much more attention to it and turning the vehicle off before it even gets hot enough for the fan to kick on high.
I guess the question is, does the fan kick on when you first start the engine up and then come down in speed/sound? If it does then the fan is most likely functioning just fine.

I would have to dig around for that invoice. but No i never hear it kick on anymore i drive 35 mins to work everyday. And im sure it would have kicked on when i went on the trails it was probably 85 out and i was going up a lot of steep hills so im pretty sure the fan would have kicked on if it was working. Heck i can just replace the thermostat anyway if i cant find the invoice, just to for sure cross that off my list of possible causes.

 

[pzy3339]

its $13 and 10 minutes to change the t-stat, couldn't hurt. when mine was going bad it would act up more often when the a/c was on and especially when the engine had been running for long periods while not moving or at low speed, then I would try to take off and it would get hot real quick and I would have to shut down and wait for it to cool. on the other hand my daily commute to work was never an issue.

from what I can tell the t-stat doesn't really go bad all at once. as the metal gets hot and cold over and over again the amount that the spring changes length and spring rate will change. when I swapped them the old one was very stiff and much harder to compress than the new one.

I would think you could do a few things to test the fan clutch issue. let the engine run at idle and monitor the temp, the fan should eventually kick on as needed. It would be pretty obvious if it just did not kick on at all, however if it does kick on and you think maybe it is slipping I would try to raise the rpms up to about 3,000 and see if there is an appropriate increase in fan speed or if the fan wont roar like it should, indicating the clutch cannot hold enough torque to spin the fan as hard as it should. it should roar pretty good when the rpms go above idle. if it will not give a good roar I would feel pretty confident that was the issue.

when I pull away after sitting idle with the a/c on and the fan is engaged it is plenty audible inside the car with the windows up. no mistaking its working. just for reference.

good luck

 

[Ford4life32]

its $13 and 10 minutes to change the t-stat, couldn't hurt. when mine was going bad it would act up more often when the a/c was on and especially when the engine had been running for long periods while not moving or at low speed, then I would try to take off and it would get hot real quick and I would have to shut down and wait for it to cool. on the other hand my daily commute to work was never an issue.

from what I can tell the t-stat doesn't really go bad all at once. as the metal gets hot and cold over and over again the amount that the spring changes length and spring rate will change. when I swapped them the old one was very stiff and much harder to compress than the new one.

I would think you could do a few things to test the fan clutch issue. let the engine run at idle and monitor the temp, the fan should eventually kick on as needed. It would be pretty obvious if it just did not kick on at all, however if it does kick on and you think maybe it is slipping I would try to raise the rpms up to about 3,000 and see if there is an appropriate increase in fan speed or if the fan wont roar like it should, indicating the clutch cannot hold enough torque to spin the fan as hard as it should. it should roar pretty good when the rpms go above idle. if it will not give a good roar I would feel pretty confident that was the issue.

when I pull away after sitting idle with the a/c on and the fan is engaged it is plenty audible inside the car with the windows up. no mistaking its working. just for reference.

good luck

Thanks for the input! I have sat at idle for a while like 20+ mins multiple times and the fan has never kicked on. It used to work when i first bought my X. It would do exactly what yours does with the A/C on at a light. So i am pretty sure that it is the clutch. I am going to change the thermostat anyways just to make sure then i will have a new clutch put in.