ac/blower questions
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From: warrenton mo
ac/blower questions
I charged the ac in my truck today. New dryer and condensor full charge 134a. Question is , any ideas on how to get better air flow from the vents? Blower is fine, well works anyway. Air is so cold I get frost on the vents! Just don't get much air flow. The back dosent get any. Thinking of taking the dash out and sealing the duct work. Anyone have an idea on how to revamp the blower box? Maybe a super blower motor lol? Im trying to figure a way to route some duct work to the back also. Thinking of running some along the floor under the seat. Maybe utilize a secondary blower to force air to the rear. Any impute or past experience?
Fleet Mechanic
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Some of the after-market blower motors are wimpy, don't know if you have an original in there.
Another common problem on older vehicles is restricted airflow through the evaporator core due to dust/fiber/crud buildup over the years.
ALL AIRFLOW goes through the evap core first, whether you have A/C on or not, as it is a reheat HVAC setup. Over the years, all the dust and stuff that gets pulled in the cowling intake vent builds up on the input side of the evaporator core, on the fins. This is greatly aggravated by any evap core refrigerant leak, as the refrigerant oil spreads out in a thin film across the fins, turning it into an oil-bath air filter, which are very effective at trapping crud.
I have pulled evap cores out of then-10/15 year old cars that looked like a dog or cat was packaged with them, a lot of thin fibrous matter built up over dirt. The more that builds up, the more it traps, the lower the airflow.
Working carefully, you could pull the two halves of the evap core covers off and clean it if that is the problem, but if it's an oil leak, well there is your refrigerant leak.
An easier check would be to pull out the blower motor from under the hood, and try to look in sideways towards the evap core with a mirror and light. An evap core that is clean looks like it is made of aluminum (it is), and you can see all of the fins with no problem. If you see a dark gray or black mess, and have trouble clearly seeing the fins, you just found the airflow problem.
New vehicles that have cabin air filters don't have this problem, IF people put a new filter in, rather than just throwing the old one away and thinking all's good because the airflow is (temporarily) stronger without the filter.
EDIT - What a coincidence! Up in the F-150 97-2003 forum, here:
https://www.ford-trucks.com/forums/1...connect-2.html
on post # 19 (on the second page) jmo1112 posted a link to another website where he has a pic of the evap core he pulled out of his 2002 F-150. That evap core is behind-the-dash mounted (ugh!), but the airflow idea is the same. So that pic is what it should NOT look like! But I have seen even worse...
Another common problem on older vehicles is restricted airflow through the evaporator core due to dust/fiber/crud buildup over the years.
ALL AIRFLOW goes through the evap core first, whether you have A/C on or not, as it is a reheat HVAC setup. Over the years, all the dust and stuff that gets pulled in the cowling intake vent builds up on the input side of the evaporator core, on the fins. This is greatly aggravated by any evap core refrigerant leak, as the refrigerant oil spreads out in a thin film across the fins, turning it into an oil-bath air filter, which are very effective at trapping crud.
I have pulled evap cores out of then-10/15 year old cars that looked like a dog or cat was packaged with them, a lot of thin fibrous matter built up over dirt. The more that builds up, the more it traps, the lower the airflow.
Working carefully, you could pull the two halves of the evap core covers off and clean it if that is the problem, but if it's an oil leak, well there is your refrigerant leak.
An easier check would be to pull out the blower motor from under the hood, and try to look in sideways towards the evap core with a mirror and light. An evap core that is clean looks like it is made of aluminum (it is), and you can see all of the fins with no problem. If you see a dark gray or black mess, and have trouble clearly seeing the fins, you just found the airflow problem.
New vehicles that have cabin air filters don't have this problem, IF people put a new filter in, rather than just throwing the old one away and thinking all's good because the airflow is (temporarily) stronger without the filter.
EDIT - What a coincidence! Up in the F-150 97-2003 forum, here:
https://www.ford-trucks.com/forums/1...connect-2.html
on post # 19 (on the second page) jmo1112 posted a link to another website where he has a pic of the evap core he pulled out of his 2002 F-150. That evap core is behind-the-dash mounted (ugh!), but the airflow idea is the same. So that pic is what it should NOT look like! But I have seen even worse...
Thread Starter
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Junior User
Joined: Apr 2012
Posts: 67
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From: warrenton mo
Some of the after-market blower motors are wimpy, don't know if you have an original in there.
Another common problem on older vehicles is restricted airflow through the evaporator core due to dust/fiber/crud buildup over the years.
ALL AIRFLOW goes through the evap core first, whether you have A/C on or not, as it is a reheat HVAC setup. Over the years, all the dust and stuff that gets pulled in the cowling intake vent builds up on the input side of the evaporator core, on the fins. This is greatly aggravated by any evap core refrigerant leak, as the refrigerant oil spreads out in a thin film across the fins, turning it into an oil-bath air filter, which are very effective at trapping crud.
I have pulled evap cores out of then-10/15 year old cars that looked like a dog or cat was packaged with them, a lot of thin fibrous matter built up over dirt. The more that builds up, the more it traps, the lower the airflow.
Working carefully, you could pull the two halves of the evap core covers off and clean it if that is the problem, but if it's an oil leak, well there is your refrigerant leak.
An easier check would be to pull out the blower motor from under the hood, and try to look in sideways towards the evap core with a mirror and light. An evap core that is clean looks like it is made of aluminum (it is), and you can see all of the fins with no problem. If you see a dark gray or black mess, and have trouble clearly seeing the fins, you just found the airflow problem.
New vehicles that have cabin air filters don't have this problem, IF people put a new filter in, rather than just throwing the old one away and thinking all's good because the airflow is (temporarily) stronger without the filter.
EDIT - What a coincidence! Up in the F-150 97-2003 forum, here:
https://www.ford-trucks.com/forums/1...connect-2.html
on post # 19 (on the second page) jmo1112 posted a link to another website where he has a pic of the evap core he pulled out of his 2002 F-150. That evap core is behind-the-dash mounted (ugh!), but the airflow idea is the same. So that pic is what it should NOT look like! But I have seen even worse...
Another common problem on older vehicles is restricted airflow through the evaporator core due to dust/fiber/crud buildup over the years.
ALL AIRFLOW goes through the evap core first, whether you have A/C on or not, as it is a reheat HVAC setup. Over the years, all the dust and stuff that gets pulled in the cowling intake vent builds up on the input side of the evaporator core, on the fins. This is greatly aggravated by any evap core refrigerant leak, as the refrigerant oil spreads out in a thin film across the fins, turning it into an oil-bath air filter, which are very effective at trapping crud.
I have pulled evap cores out of then-10/15 year old cars that looked like a dog or cat was packaged with them, a lot of thin fibrous matter built up over dirt. The more that builds up, the more it traps, the lower the airflow.
Working carefully, you could pull the two halves of the evap core covers off and clean it if that is the problem, but if it's an oil leak, well there is your refrigerant leak.
An easier check would be to pull out the blower motor from under the hood, and try to look in sideways towards the evap core with a mirror and light. An evap core that is clean looks like it is made of aluminum (it is), and you can see all of the fins with no problem. If you see a dark gray or black mess, and have trouble clearly seeing the fins, you just found the airflow problem.
New vehicles that have cabin air filters don't have this problem, IF people put a new filter in, rather than just throwing the old one away and thinking all's good because the airflow is (temporarily) stronger without the filter.
EDIT - What a coincidence! Up in the F-150 97-2003 forum, here:
https://www.ford-trucks.com/forums/1...connect-2.html
on post # 19 (on the second page) jmo1112 posted a link to another website where he has a pic of the evap core he pulled out of his 2002 F-150. That evap core is behind-the-dash mounted (ugh!), but the airflow idea is the same. So that pic is what it should NOT look like! But I have seen even worse...
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