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Discussion Starter #1
Hey all, I have a cooling issue. I recently converted my A/C to R134 which wasn't working due to low Freon. Anyway, now when I run my A/C my temp gauge goes all the way to around 250*. When I don't run the A/C the temp gauge runs around 150*. Now, I have installed a new water pump, 165* thermostat, clutch fan and radiator. What is my problem? All of the parts came from my local AutoZone. Could my radiator not be big enough for my A/C? Could I have the wrong water pump (non reverse). Oh yeah, the temp is even running at 70 mph down the interstate not stop and go traffic.

Thanks
Scott
 

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Ok I will help you out without trying to write book.

Parts you wll need to buy autozone
1. temp computer sender ($15?)
2. temp guage sender ($15?)
3. thermostat and 180 degree ($10?) get a fail safe one with a little hole in the thermostat.
4. r134 a/c pressure switch ($15)
One is located on the fuel rail on passenger side. The other is located on the front right intake.

First take out the 165 degree thermostat. Get a 180 degree or the factory 192 will work just fine. With the 165 it is too cool and your computer will be in "warmup mode" so it will depend on your o2 sensors and will always run rich(too much gas). Your stock radiator is great! The stock foxbody radiator is a good radiator. There are people that run 347s and 331s with a list of mods using there stock radiator with no issues.

Doing a cheap convertion kit to R134 was way wrong. Since you did do the R134 you will need a R134 pressure switch instead of the r12. So your compresser can kick on.
You do the research. Good luck
 

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also check if the fan clutch is good, since running the a/c ads heat to the radiator due to the condenser being in front of the radiator, if your fan clutch is bad it wont pull enough air to keep it cool, and teps will ump once your stopped, and stay steady while you drive, i would change your t-stat to a 180 degree as wel
 

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does the temp jump up at once or does it take a few minutes. if it does start looking for a short. Ran into that issue five years or so ago.
 

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I currently experience that EXACT issue as well.
it was convert to R134A before I bought it so I don't know if they did a good job or not.

Water pump is new, 180 thermostat new, radiator flushed.

Once I finish fixing my current stuff I'm going to try swapping in a new AC Compressor.
 

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Discussion Starter #6
Sorry guys, I have been very busy at work this week. Anyway, how does the conversion effect the coolant temp? Does the 134 mixing with what little freon make it hot enough that when the air hits the condensor that it heats the air going through the radiator? I don't understand this!

Parts you will need to buy autozone
1. temp computer sender ($15?)
2. temp guage sender ($15?)
3. thermostat and 180 degree ($10?) get a fail safe one with a little hole in the thermostat.
4. r134 a/c pressure switch ($15)
One is located on the fuel rail on passenger side. The other is located on the front right intake.


Why do I need these parts? And yes, the fan clutch is new.

Scott
 

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Ok I will help you out without trying to write book.

Parts you wll need to buy autozone
1. temp computer sender ($15?)
2. temp guage sender ($15?)
3. thermostat and 180 degree ($10?) get a fail safe one with a little hole in the thermostat.
4. r134 a/c pressure switch ($15)
One is located on the fuel rail on passenger side. The other is located on the front right intake.

First take out the 165 degree thermostat. Get a 180 degree or the factory 192 will work just fine. With the 165 it is too cool and your computer will be in "warmup mode" so it will depend on your o2 sensors and will always run rich(too much gas). Your stock radiator is great! The stock foxbody radiator is a good radiator. There are people that run 347s and 331s with a list of mods using there stock radiator with no issues.

Doing a cheap convertion kit to R134 was way wrong. Since you did do the R134 you will need a R134 pressure switch instead of the r12. So your compresser can kick on.
You do the research. Good luck
I agree with the 180 T-stat, but all the other stuff is just throwing parts at it having no clue what's actually bad... diagnosis needs to happen before replacing parts...
Throwing random parts at a car is a good way to waste money without fixing the problem.

Also, with too cool of a thermostat causing it to not fully warm up, it will be in "open loop" which means that the computer won't pay any attention to the O2 sensors.
 

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any a/c system will intoduce heat into the radiator from it cooling the refrigerant before the coolant, so i have seen a few cars run hot because of a bad fan clutch when the a/c is on, not just mustangs, that would be y first guess, check to see if you can spin the fan with the engine OFF, if it spins real easy its time for a new one, there should be some resistance to it, if you take it off the car, there's a spring on it, you can turn the spring to make it full lock manually, drive the car a short bit with it like that to see if that fixes the problem, if so you need a new fan clutch. dont just turn the spring and leave it that way, the fan isnt meant to spin to such high rpm's and since its on a direct drive theres a possibility it will come apart.
 

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Discussion Starter #9
Thanks guys, I will replace the thermostat tomorrow and make sure I have the coolant at a 50/50 ratio. I may even add some of that water wetter stuff. As far as the fan and clutch goes, :wavey THEY ARE NEW! :wavey As stated multiple times above, the fan and clutch are new. I am not trying to be a smart a$$ just wanted to make sure that it is noticed this time.

Scott
 

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oh, wow sorry i didnt even read that, guess im just blind, sorry about that lol, my guess would be the thermostat as well. my bad on the fan clutch thing.
 

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R134 runs a much hotter condensor than R12

R134 runs a much hotter condensor than R12.

So yoou need to have a good solid cooling system.
T-stat to 180 or 192 (I have 180). 165 is useless, it will just stay open and not allow any time for the rad to cool down the coolant.

Next is airflow. You need a good funcitoning fan clutch. Yours is new so I assume that it tightens as expected wen hot.

Greg
 

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Did you ever figure out what the problem was?
 

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Discussion Starter #13
Ok, here is what I have noticed. I changed the thermostat out to a 180* piece and left the car running for about 10 minutes with no issues whatsoever. I then turned the A/C on and within a couple of minutes there was coolant flowing out of my overflow bottle. I then checked the temp guage and the reading was about half way so that was fine. I shut the car off and went back to check it after it had cooled and the overflow bottle was still full and the radiator was empty. Why didn't the coolant flow back into the radiator after it cooled? Anyway, I have tested this many times with the same result and the water never flows back into the radiator, I have to add to it. I even checked it this morning and after about 10 minutes with the air on, the coolant overflow was full and running out. The temp this morning was in the mid 60's but it does it no matter what the temp is outside. What to check next? Do I have a bad radiator cap which wouldn't allow it to pull the coolant from the overflow?

Scott
 

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Air is getting in somehow. During the cooling process a vacuum is created to pull the now cool water from the expansion tank back to the radiator. Check the seal on your radiator cap and hose connections(make sure they're clipped properly).
 
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