running hot only when a/c is on??

jjreece · September 28th, 2010, 02:03 PM

Hey guys,

My cobra just hit over 100k and started running hot, so i replaced the radiator and put a 180 degree thermostat in, and now it runs around the "O" on the temp. gauge except when the a/c is on, then it heats up to the "A" or a little past. It doesn't completely overheat, and it does this whether i'm driving in the city or on the highway. I'm completely lost with this one, any ideas??

Bullitt95 · September 29th, 2010, 01:14 AM

Three things to check:

1. Does the AC system have enough refrigerant?
2. Does the AC compressor pulley spin freely?
3. Does the drivebelt have enough tension (not bottoming out the tensioner)?

Siljin · September 29th, 2010, 01:37 AM

I'm having a similar problem to this but its not AC related, its just getting hot all the time now. I did just put a new drivebelt on it and I think it may be bottoming out the tensioner or very close to, its a 104.5" belt. Car is running in between the M and A in NORMAL. I let the car sit an hour after driving it home went out and felt around under the hood, there was alot of heat transfer pretty much everywhere.

hotmustang95 · September 29th, 2010, 12:52 PM

Sounds all normal to me. Since the day I bought my car it always ran hot. Now I don't know how hot since there's no real gauge to tell you, only the regular NORMAL gauge. Mine always ran around the A. After about 5 years of different setups I finally got it down. No more overheating for me.

jjreece · September 29th, 2010, 01:10 PM

Originally Posted by Bullitt95

Three things to check:

1. Does the AC system have enough refrigerant?
2. Does the AC compressor pulley spin freely?
3. Does the drivebelt have enough tension (not bottoming out the tensioner)?

Yes to all 3, lol my fan runs constantly b/c one of the terminals is melted on the plug, but i have a new plug coming, and i'm also getting a new ccrm in hopes of fixing this, but this should have no effect on it running hot at highway speeds i would think right?

Bullitt95 · September 29th, 2010, 02:12 PM

Correct. If your engine's still running hot on the highway there may be another issue e.g. overadvanced or retarded timing.

jjreece · September 30th, 2010, 04:57 PM

Originally Posted by Bullitt95

Correct. If your engine's still running hot on the highway there may be another issue e.g. overadvanced or retarded timing.

hmmm ok, i'll check that out. thanks guys.

September 28th, 2010, 02:03 PM	#1
jjreece Newbie 1994 mustang cobra Join Date: May 2010 Location: tampa, fl Posts: 26 iTrader: 0 reviews	running hot only when a/c is on?? Hey guys, My cobra just hit over 100k and started running hot, so i replaced the radiator and put a 180 degree thermostat in, and now it runs around the "O" on the temp. gauge except when the a/c is on, then it heats up to the "A" or a little past. It doesn't completely overheat, and it does this whether i'm driving in the city or on the highway. I'm completely lost with this one, any ideas??

September 29th, 2010, 01:14 AM	#2
Bullitt95 Hardcore Enthusiast 1995 Mustang GT auto 13.546 @ 105.32 Join Date: Apr 2007 Location: Al Ain, UAE Posts: 1,452 iTrader: 0 reviews	Three things to check: 1. Does the AC system have enough refrigerant? 2. Does the AC compressor pulley spin freely? 3. Does the drivebelt have enough tension (not bottoming out the tensioner)? __________________ 243.5rwhp/284.2rwtq Mod list in My Garage

September 29th, 2010, 12:52 PM	#4
hotmustang95 Regular Last of the 302's Road Racing Rookie Join Date: Sep 2009 Location: Boynton Beach, FL Posts: 373 iTrader: 0 reviews	Sounds all normal to me. Since the day I bought my car it always ran hot. Now I don't know how hot since there's no real gauge to tell you, only the regular NORMAL gauge. Mine always ran around the A. After about 5 years of different setups I finally got it down. No more overheating for me. __________________ Victor ( goofyfeet) Oliver P.B.M.C. Member Track Addict

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September 29th, 2010, 01:37 AM	#3
Siljin Newbie 1995 Mustang GT Join Date: Sep 2010 Location: San Diego Posts: 11 iTrader: 0 reviews	I'm having a similar problem to this but its not AC related, its just getting hot all the time now. I did just put a new drivebelt on it and I think it may be bottoming out the tensioner or very close to, its a 104.5" belt. Car is running in between the M and A in NORMAL. I let the car sit an hour after driving it home went out and felt around under the hood, there was alot of heat transfer pretty much everywhere.

September 29th, 2010, 02:12 PM	#6
Bullitt95 Hardcore Enthusiast 1995 Mustang GT auto 13.546 @ 105.32 Join Date: Apr 2007 Location: Al Ain, UAE Posts: 1,452 iTrader: 0 reviews	Correct. If your engine's still running hot on the highway there may be another issue e.g. overadvanced or retarded timing.

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