78 air conditioning problem... overheating
Thread Starter
Racer
Joined: Apr 2006
Posts: 364
Likes: 0
From: Setauket New York
78 air conditioning problem... overheating
When i use the air conditioning on my 78 l82 on the highway, the car begins to overheat. It works fine at low speeds with the AC on, but when i get to about 70+mph, the temp gauge begins to go up. Does anyone know what may be causing this problem?
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
Your fan clutch may need replacing. As the clutch gets older they seep and stop locking up at high temps.
Try this:
When the engine is running and hot, pop the hood and watch the fan. Turn the engine off and count how many times the fan spins once it's off.
If it seems to spin freely it's gonna need a new one. If it stops within a turn or two then that may not be the problem.
Try this:
When the engine is running and hot, pop the hood and watch the fan. Turn the engine off and count how many times the fan spins once it's off.
If it seems to spin freely it's gonna need a new one. If it stops within a turn or two then that may not be the problem.
Thread Starter
Racer
Joined: Apr 2006
Posts: 364
Likes: 0
From: Setauket New York
Your fan clutch may need replacing. As the clutch gets older they seep and stop locking up at high temps.
Try this:
When the engine is running and hot, pop the hood and watch the fan. Turn the engine off and count how many times the fan spins once it's off.
If it seems to spin freely it's gonna need a new one. If it stops within a turn or two then that may not be the problem.
Try this:
When the engine is running and hot, pop the hood and watch the fan. Turn the engine off and count how many times the fan spins once it's off.
If it seems to spin freely it's gonna need a new one. If it stops within a turn or two then that may not be the problem.
Race Director
Joined: Feb 2005
Posts: 16,100
Likes: 17
My 78 L-82 ran at higher temps using A/C at hwy speeds...in my case,my radiator had lost efficiency due to lower tube clogging...if you hear your fan engaging at lower speeds,the clutch is probably ok as most dis-engage at highway speeds anyway...
You might try a good flush of your system and clean your radiator surface...some other simple things to check are radiator seals, front air dam,etc..then go from there...
What temps were you experiencing ?
My cure was a new Dewitts Alum Radiator...temps do not go over 200 F at hwy speeds in 100 F ambient air with A/C on...
Rich
You might try a good flush of your system and clean your radiator surface...some other simple things to check are radiator seals, front air dam,etc..then go from there...
What temps were you experiencing ?
My cure was a new Dewitts Alum Radiator...temps do not go over 200 F at hwy speeds in 100 F ambient air with A/C on...
Rich
