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Discussion Starter · #1 ·
Hello everyone i have a 02 7.3, my heat is really hot but when i put it on the dash vents it has no pressure and barely comes out.. Im pretty sure i just need to change the filter truck has 322,00 miles and is original filter. but if you think its something else let me know. winter is coming and want strong heat. Also if it's the filter i want to know where the filter is and how to change it. Thanks.
 

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If you're talking cabin filter, there is not one on a Superduty.

But you should check the grille below the windshield for crud. It may also be that the heater core is obstructed with stuff that's been sucked in, or the blend door that directs the air where you want it isn't working correctly. It's vacuum operated.

What do you mean winter is coming? IT'S HERE! It was Zero F at my house this morning. :surprise:
 

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Discussion Starter · #3 ·
Could it be my vacuum pump? My brakes are a little spongy as well.
 

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The 02 7.3 doesn't use vacuum for brakes. It uses the power steering pump to feed a hydraboost system.

If you had weak vacuum, your first symptom would be the vent doors defaulting to defrost. If you are getting air flow from the defrost when the position dial is set to vent, you need to explore a vacuum issue. The most likely cause would be a vacuum leak. If you have 4WD, the front hubs or the lines going to them are frequently to blame.

If you have no air coming from the defrost, you need to check for obstructions. The evaporator core and heater core frequently get plugged with debris. Leaves, moisture, dirt, hair, dust over time make a detritus that can completely obstruct the airflow. A good cleaning never hurt. Another issue could be the blower motor. I would suggest pulling that anyway to get eyes in the system and you can check the fan speed and blower wheel condition while its out. I've seen wheels that were so entrapped with dirt that I couldn't see how they were moving any air.

Check those things first and let us know what you find.
 

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Discussion Starter · #5 ·
ok i will check those and report back, i can hear my fan spinning fast on the hight speeds, so i think i may just have some stuff clogged in the evaporator core. how should i go about cleaning that out?
 

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The case splits under the hood giving you very tight access. It's still worth it to clean it. I brush off the layer of crap on the surface, then use coil cleaner. You can buy it in spray form at Hime Depot or get it by the gallon at your HVAC supply house. Then, I get a wet dry vacuum with the crevice tool at the bottom of the box and use my garden hose with a jet nozzle to flush the box and core (both sides) completely clean.


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Hello everyone i have a 02 7.3, my heat is really hot but when i put it on the dash vents it has no pressure and barely comes out.. Im pretty sure i just need to change the filter truck has 322,00 miles and is original filter. but if you think its something else let me know. winter is coming and want strong heat. Also if it's the filter i want to know where the filter is and how to change it. Thanks.
Do you mean you have heat from some vents but just not your "dash vents? How about the window defrost vents? Do your floor vents blow out hot?

Does the force of the air increase out of the vents when you turn your fan on the different speeds (or just sound louder) when you have your floor vents on? When you have your defrost vents on?
 
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