1981 cooling issue
Thread Starter
Heel & Toe
Joined: Nov 2011
Posts: 19
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1981 cooling issue
I have notice that temp gauge nears red line after driving at 70 mph for a long period of time. When I reduce speed it begains to lower temp to 225 degrees.[Any suggestions/solutions appreciated.
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
You are not likely to actually see the hose collapsed, by the time you pull off the road and pop the hood to check it the thing may have gone back to normal looking. When its warmed up good, feel the hose, see if its soft and easy to collapse. There is supposed to be a spring in there to prevent this.
High speed heat can also be the air dam not in place or distorted, and radiator seals missing.
Might be a good time to verify ignition timing also.
High speed heat can also be the air dam not in place or distorted, and radiator seals missing.
Might be a good time to verify ignition timing also.
Le Mans Master
Joined: Aug 2010
Posts: 5,339
Likes: 546
From: Central Texas
The factory electric fan doesn't turn on until roughly 248. The sensor for the fan can be changed by going to one that turns on earlier. Summit has an abundance of choices. You might try shorting the fan so it runs all the time and see if that cools it down. The lower number temperature sensor fixed the problem on my '81.
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Thread Starter
Heel & Toe
Joined: Nov 2011
Posts: 19
Likes: 0
1981 cooling issues
The factory electric fan doesn't turn on until roughly 248. The sensor for the fan can be changed by going to one that turns on earlier. Summit has an abundance of choices. You might try shorting the fan so it runs all the time and see if that cools it down. The lower number temperature sensor fixed the problem on my '81.
Burning Brakes
Joined: May 2008
Posts: 1,116
Likes: 5
From: Middleburg Florida
The aux fan doesn't cause high heat and is intended for the exception, not the rule. It also comes on when the AC is on. The problem isn't likely the fan. Is the cap good? Is your lower air dam complete and in place? What about the clutch fan? Is in in place and working properly? Those would be my first suspects....
Le Mans Master
Joined: Aug 2010
Posts: 5,339
Likes: 546
From: Central Texas
I haven't run my a/c recently. My auxiliary fan still comes on at 200 and shuts off at 185 with the sensor I bought at Summit. It solved my overheating problem when I changed to the new sensor. Not saying this is his problem. Simply giving him something he might want to change. That factory sensor (turn on 238) lets your car get hot before it even triggers the auxiliary fan to turn on.
Last edited by Street Rat; Sep 28, 2012 at 05:08 PM.
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
The Aux fan does not come on with the AC on an 81 unless its been modified, it comes on at 238 like posted above. The sensor has 2 contacts that are the switch contacts. This is different than say an idiot light, those have 1 terminal and switches internally to ground.
Kep in mind that the aux fan on an 81 is 31 years old. The technology has improved so much its not even funny. I would take the oportunity to lose the entire engine driven fan and shroud and go straight electric. There are many choices out there, check Summit, Jegs, Speedway etc...
Kep in mind that the aux fan on an 81 is 31 years old. The technology has improved so much its not even funny. I would take the oportunity to lose the entire engine driven fan and shroud and go straight electric. There are many choices out there, check Summit, Jegs, Speedway etc...
