1999 GT overheating problem
06-28-2007, 06:28 PM
#1
Thread Starter
Join Date: Jun 2007
Location:
Posts: 2
1999 GT overheating problem
I have a 1999 GT that overheats ONLY when the airconditioner is running. I can cruise all day with no A/C and not have an overheating problem. But as soon as I throw on the A/C within 20 minutes I'll peg the temp gauge on the hot side.
I'm running a Procharger P1SC with intercooler and usual upgrades (injectors, pump)so I know that is taxing the cooling system some. However, this problem existed prior to installing the supercharger so it cannot be the reason.
I have flushed the radiator,replaced the temp sending unit, and replaced the thermostat. I'm at a loss as to what to do next. Any suggestions??
I'm running a Procharger P1SC with intercooler and usual upgrades (injectors, pump)so I know that is taxing the cooling system some. However, this problem existed prior to installing the supercharger so it cannot be the reason.
I have flushed the radiator,replaced the temp sending unit, and replaced the thermostat. I'm at a loss as to what to do next. Any suggestions??
06-28-2007, 11:30 PM
#2
3rd Gear Member
Join Date: Nov 2006
Location:
Posts: 641
RE: 1999 GT overheating problem
You ARE pushing the limits of the factory cooling system. I had similar problems with my car after the KB install when summer arrived. I tried every trick I could to correct the problem, but with the high under-hood temps that the KB produces it was a futile attempt. I put a Fluidyne radiator in it and solved the problem to a certain extent. I will be getting a heat extractor or cowl induction hood to further cool things down. I now know why Ford put a heat extractor hood on the 03-04 Cobra.
Some of the things I tried/learned during my ordeal:
Make sure your fan is properly working. Most people don't know it has two speeds. The low speed will come on when the car is cold and the a/c is turned on. The factory high speed setting is 198* if I remember correctly.
Make sure your car still has the lower air damn mounted to the lower radiator support. It does make a difference.
My factory radiator was pretty clogged up on 1/4 of it thatwasn't covered by the evap coil.
I tried "Water Wetter" from Red Line oil and a 75% water / 25% coolant mix and it helped a little.
I assume you have "burped" the system to get the air out. I drilled a 1/16 hole in the thermostat to allow any trapped air to escape.
Good luck man. I highly recommend the Fluidyne Radiator.
Some of the things I tried/learned during my ordeal:
Make sure your fan is properly working. Most people don't know it has two speeds. The low speed will come on when the car is cold and the a/c is turned on. The factory high speed setting is 198* if I remember correctly.
Make sure your car still has the lower air damn mounted to the lower radiator support. It does make a difference.
My factory radiator was pretty clogged up on 1/4 of it thatwasn't covered by the evap coil.
I tried "Water Wetter" from Red Line oil and a 75% water / 25% coolant mix and it helped a little.
I assume you have "burped" the system to get the air out. I drilled a 1/16 hole in the thermostat to allow any trapped air to escape.
Good luck man. I highly recommend the Fluidyne Radiator.
06-29-2007, 03:01 PM
#3
Thread Starter
Join Date: Jun 2007
Location:
Posts: 2
RE: 1999 GT overheating problem
Thanks for the input. I have checked the fan....2 speeds working OK. Front air dam is in place. I forgot to mention that I also put in a new water pump.
I found a few threads that also mentioned the "burp". I had not done that until yesterday. I simply took the radiator cap off and ran the car for 4-5 minutes. I did not see a true burp however. Should I see air bubbles??
While doing the burp I did notice that the resevoir started with fluid just a bit below the fill line and as the engine got warm the fluid came verynear the top. Could this mean that my coolant isn't flowing well??
Is there any way that I have a problem with my A/C system that would cause the overheating??
I found a few threads that also mentioned the "burp". I had not done that until yesterday. I simply took the radiator cap off and ran the car for 4-5 minutes. I did not see a true burp however. Should I see air bubbles??
While doing the burp I did notice that the resevoir started with fluid just a bit below the fill line and as the engine got warm the fluid came verynear the top. Could this mean that my coolant isn't flowing well??
Is there any way that I have a problem with my A/C system that would cause the overheating??
06-29-2007, 03:26 PM
#4
2nd Gear Member
Join Date: Mar 2006
Posts: 206
RE: 1999 GT overheating problem
I had the same issue in my 96 GT. Though your radiator is better. I just changed to an all aluminum 2 row radiator and running AC nipple freezing cold I get to the edge of the r in stop and go traffic.
06-29-2007, 10:07 PM
#5
3rd Gear Member
Join Date: Nov 2006
Location:
Posts: 641
RE: 1999 GT overheating problem
ORIGINAL: plong67
Thanks for the input. I have checked the fan....2 speeds working OK. Front air dam is in place. I forgot to mention that I also put in a new water pump.
I found a few threads that also mentioned the "burp". I had not done that until yesterday. I simply took the radiator cap off and ran the car for 4-5 minutes. I did not see a true burp however. Should I see air bubbles??
Generally not. Usually air gets trapped behind the thermostatafter draining the block, changing the water pump or replacing theradiator. When the air buildsup behind the thermostat, thehot coolant can't heat the thermostat properly to allow it to open. That is wheredrilling a small hole, (1/16th"), in the thermostat will allow any trapped air out. If your car only overheats with the A/C on, I doubt it's a trapped air issue.
While doing the burp I did notice that the reservoir started with fluid just a bit below the fill line and as the engine got warm the fluid came verynear the top. Could this mean that my coolant isn't flowing well??
Quitethe contrary. When water is heated it expands. Since water is not compressible, the extra volume created by expansion must go someplace. That's why it's called an expansion tank. It's perfectly normal and it tells you that your thermostat is opening.
Is there any way that I have a problem with my A/C system that would cause the overheating??
I wouldn't think so. You have to remember that using A/C generally will heat up an average cars water temp by 5-10 deg. The a/c condensercoil in front of your radiator becomes heat soaked while running the a/c. The air passing through thecondenser coilentering your radiator may be 10-20 deg. hotter than the ambient air temp. Plus the additional load of turning the compressor aids in heating the coolant.. You didn't help your situation any with your inter-cooler sitting in front of the radiator either.
Thanks for the input. I have checked the fan....2 speeds working OK. Front air dam is in place. I forgot to mention that I also put in a new water pump.
I found a few threads that also mentioned the "burp". I had not done that until yesterday. I simply took the radiator cap off and ran the car for 4-5 minutes. I did not see a true burp however. Should I see air bubbles??
Generally not. Usually air gets trapped behind the thermostatafter draining the block, changing the water pump or replacing theradiator. When the air buildsup behind the thermostat, thehot coolant can't heat the thermostat properly to allow it to open. That is wheredrilling a small hole, (1/16th"), in the thermostat will allow any trapped air out. If your car only overheats with the A/C on, I doubt it's a trapped air issue.
While doing the burp I did notice that the reservoir started with fluid just a bit below the fill line and as the engine got warm the fluid came verynear the top. Could this mean that my coolant isn't flowing well??
Quitethe contrary. When water is heated it expands. Since water is not compressible, the extra volume created by expansion must go someplace. That's why it's called an expansion tank. It's perfectly normal and it tells you that your thermostat is opening.
Is there any way that I have a problem with my A/C system that would cause the overheating??
I wouldn't think so. You have to remember that using A/C generally will heat up an average cars water temp by 5-10 deg. The a/c condensercoil in front of your radiator becomes heat soaked while running the a/c. The air passing through thecondenser coilentering your radiator may be 10-20 deg. hotter than the ambient air temp. Plus the additional load of turning the compressor aids in heating the coolant.. You didn't help your situation any with your inter-cooler sitting in front of the radiator either.
I do not have a cent. blower so I have no clue to how much they raise under-hood temps. The fact that you stated you had this problem before the blower install makes me want to guess a partially clogged radiator. Either internally or externally.If it was a head gasket issue, the car would get hot with or with out the a/c. The fans are working, rule that out. The thermostat is opening because your coolant level in your expansion tank is rising like it should. The cheaper way to go is to pull your radiator and have it flushed/cleaned if it's in good shape. Or, drop 4 large for a Fluidyne. That's a lot of money, I know. But it sure is pretty.
Thread
Thread Starter
Forum
Replies
Last Post
mungodrums
S550 2015-2023 Mustang
7
09-29-2015 09:18 PM
yourmom6990
Archive - Parts For Sale
2
09-14-2015 10:52 PM
