A/C causes overheating!
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New User
Joined: Jan 2003
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A/C causes overheating!
I have an '85 model BroncoII with AT and the 2.8 engine.
I have a problem with overheating when using the AC.
I have replaced the 192 thermostat with a 180 and now
a 160. The problem continues. The operating temperature
gradually creeps up to the highest mark in the normal range
and might go higher, but I always turn off the AC at that
point. After turning off the AC the temperature reading slowly
drops back to mid-level normal area.
I have considered adding an auxilllary fan. I also saw a product
in one of the stores (Advance) recently that is apparently an
additive for the cooling system. It come it a large bottle like
coolant, but says on the can that it is like having "ice water"
in your cooling system. Does anyone have an experience with
this product?
Any help would be appreciated. Enjoy the forum!
Gary
I have a problem with overheating when using the AC.
I have replaced the 192 thermostat with a 180 and now
a 160. The problem continues. The operating temperature
gradually creeps up to the highest mark in the normal range
and might go higher, but I always turn off the AC at that
point. After turning off the AC the temperature reading slowly
drops back to mid-level normal area.
I have considered adding an auxilllary fan. I also saw a product
in one of the stores (Advance) recently that is apparently an
additive for the cooling system. It come it a large bottle like
coolant, but says on the can that it is like having "ice water"
in your cooling system. Does anyone have an experience with
this product?
Any help would be appreciated. Enjoy the forum!
Gary
Postmaster
Joined: Jan 2003
Posts: 4,417
Likes: 3
From: Durham, NC
A/C causes overheating!
Based on the age of your Bronco, I would say that your radiator
is probably partially blocked with mineral deposits. In this case,
the best thing to do is replace the radiator.
is probably partially blocked with mineral deposits. In this case,
the best thing to do is replace the radiator.
Senior User
Joined: Jun 2003
Posts: 439
Likes: 0
From: Burnsville, MN
A/C causes overheating!
Both points are good, lowering the thermostat temp doesn't alter your vehicles ability to shed heat. I believe that your radiator is probably plugged and if so - your heater core may also be plugged which will be an issue if you were in a colder climate.
Does the overheating occur at speeds greater than 25 mph? If so, it would more implicate the radiator over the fan clutch. The problem is a partially plugged radiator will not transfer enough heat to the airstream to engage a fan clutch, making the vehicle even more prone to overheating.
I'd pull the radiator and take it to a radiator shop, have them hot tank it (if it is brass) and have a flow check done. When I worked at a radiator shop this was a service we provided at a very low rate as it doesn't involve any labor.
Good luck!
Does the overheating occur at speeds greater than 25 mph? If so, it would more implicate the radiator over the fan clutch. The problem is a partially plugged radiator will not transfer enough heat to the airstream to engage a fan clutch, making the vehicle even more prone to overheating.
I'd pull the radiator and take it to a radiator shop, have them hot tank it (if it is brass) and have a flow check done. When I worked at a radiator shop this was a service we provided at a very low rate as it doesn't involve any labor.
Good luck!
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New User
Joined: Jan 2003
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A/C causes overheating!
Thanks for the responses. Speed doesn't seem to be a factor...
it will overheat idling in the driveway or driving down the interstate highway. I replaced the heater core last fall when all the windows fogged up every time it rained.
I plan on taking it by a radiator shop and having it checked.
Thanks again for your help! Gary
it will overheat idling in the driveway or driving down the interstate highway. I replaced the heater core last fall when all the windows fogged up every time it rained.
I plan on taking it by a radiator shop and having it checked.
Thanks again for your help! Gary
Post Fiend
Joined: Jun 2002
Posts: 13,873
Likes: 3
From: Atlanta GA
A/C causes overheating!
Start your engine cold and run your engine without the radiator cap on. You should see a fair amount of coolant swirling around once the thermostat opens and it will surge a bit too. This will happen even with a bad radiator. Wear eye protection while doing this.
If you are getting nothing, I would suspect a bad water pump since it overheats on the highway too, when even a marginal system will be okay (until you stop).
If you replace the water pump, make sure the gasket is lined up properly when replacing it. Have the system power flushed to clean the block and then back power flushed to flush your new heater core. If you have an air compressor, I think Sears still sells the kit if you want to do it yourself. You should not need much of an air compressor and one of the portable rentals from Home Depot should do.
Otherwise, its worth the $50 most places charge to do it.
Power flush, fill with water, drive home, empty cooling system, change the pump, fill with new anti-freeze.
If you are getting nothing, I would suspect a bad water pump since it overheats on the highway too, when even a marginal system will be okay (until you stop).
If you replace the water pump, make sure the gasket is lined up properly when replacing it. Have the system power flushed to clean the block and then back power flushed to flush your new heater core. If you have an air compressor, I think Sears still sells the kit if you want to do it yourself. You should not need much of an air compressor and one of the portable rentals from Home Depot should do.
Otherwise, its worth the $50 most places charge to do it.
Power flush, fill with water, drive home, empty cooling system, change the pump, fill with new anti-freeze.
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