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'93 Ford Bronco XLT 5.8L black w/ grey interior 215k miles
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Discussion Starter #1
I have a situation on my 93 XLT 5.8 Bronco, under normal driving conditions it gets really warm inside the cab feels like its coming from under the dash on both driver/passenger sides. No heat or air gauges are on just normal driving, you can feel it start to get warmer inside the cab but no overheating issues?
Any ideas?
 

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85 Bronco, 309ci I6 w/4bbl, np435, 4" lift, 37" Irok NDs, 4.56 w/ Detroit Locker and tru trac
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Is the heater knob on hot, and is there any air blowing out the vents? Sometimes the HVAC system goes wonky and blows air even if its off.

Do you still have the factory exhaust and heat shields? Clogged cats can really heat things up.
 

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'93 Ford Bronco XLT 5.8L black w/ grey interior 215k miles
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12 Posts
Discussion Starter #3
Is the heater knob on hot, and is there any air blowing out the vents? Sometimes the HVAC system goes wonky and blows air even if its off.

Do you still have the factory exhaust and heat shields? Clogged cats can really heat things up.
Knob is turned all the way cold. No air coming from vents.
Clogged cats? assuming clogged catalytic converter?
Exhaust pipe has changed but nothing else
 

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Yo Gilly,
  • Blower Motor Does Not Operate Properly
  • Blower motor.
  • Insufficient Cooling
  • Low refrigerant charge.
  • No Switching Between Function Selections
  • Vacuum leak.

Control Panel Diagrams & Overview in 92-96; "...In the OFF position, all doors are in the vacuum-applied position with the exception of the PANEL door. The blower & compressor clutch circuits are not energized. In the MAX A/C position, all vacuum operated doors are in the vacuum position. A/C damper inlet door (19C802) air is shut off and the passenger compartment air is recirculated to maximize cooling. Discharge is through panel register. A/C clutch & blower circuits are energized. In the NORM A/C position, outside air is allowed to enter the passenger compartment. The air passes through the A/C evaporator core (19860) and is cooled before reaching the passenger compartment. Discharge is through panel register. A/C clutch & blower circuits are energized. Ventilation is delivered through the instrument panel registers when the function selector knob in the A/C control (19980) is set in the VENT position. In the VENT position, no vacuum is applied to the OUTSIDE/RECIRC. vacuum control motor (18A318 ) and the door is open to the outside. The air coming in through the cowl is discharged through the panel registers. The blower circuit is energized, but the A/C clutch is not. In the FLOOR position, no vacuum is applied to the vacuum control motor and the OUTSIDE/RECIRC. door is open to the outside. Air is discharged through the heater outlet floor ducts (18C433) with a small amount going to the windshield defroster hose nozzles (18490). The blower circuit is energized, but the A/C clutch is not. In the MIX position, outside air is discharged through the windshield defroster hose nozzles and the heater outlet floor ducts. A/C clutch & blower circuits are energized. In the DEFROST position, outside air is discharged through the windshield defroster hose nozzles with a small amount going to the heater outlet floor ducts. All doors are in the no vacuum position. A/C clutch is engaged in ambient temperatures above approximately 10�C (50�F) & the blower circuit is energized. The PANEL/FLOOR, FLOOR/DEFROST and OUTSIDE/RECIRC doors are vacuum operated. For maximum cooling, the temperature knob should be set in its fully counterclockwise position; the function knob should be in the MAX A/C position; and the blower motor (18527) should be set for a desired rate of airflow. Even though the function knob is on MAX A/C, the temperature knob, being manually controlled, may be set to modify the temperature of the air and the path through which the air flows. Another characteristic of the MAX A/C setting is the increased noise level of the blower motor. Speed does not change when the OUTSIDE/RECIRC. door is moved to either of its two positions. The difference in noise level is that an open recirculation door exposes the passenger compartment directly to the noise. When insulated against the noise with the recirculation passageway closed, the speed appears to be less. The control knob operates an A/C switch that is attached to the backside of the A/C control by one screw and retainer tabs. Five hoses (black, white, red, blue, yellow) extend from the A/C control just below the electrical connector for the mode selector switch to the vacuum control motors and vacuum supply. The solid black hose goes to the vacuum supply through a tee-shaped A/C vacuum check valve (19A563), which attaches the A/C vacuum reservoir tank and bracket (19A566) and engine source. The white hose actuates the OUTSIDE/RECIRC. air door two-position vacuum control motor. The blue hose actuates the FLOOR/PANEL air door two-position vacuum control motor. The red and yellow hoses actuate the FLOOR/DEFROST three-position air vacuum control motor. Each end of each hose slides onto the nipple of the vacuum port to which it attaches..."
 

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85 Bronco, 309ci I6 w/4bbl, np435, 4" lift, 37" Irok NDs, 4.56 w/ Detroit Locker and tru trac
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12,366 Posts
Knob is turned all the way cold. No air coming from vents.
Clogged cats? assuming clogged catalytic converter?
Exhaust pipe has changed but nothing else
Correct, a clogged catalytic converter will cause sluggish performance and excess heat.
 

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1986 Eddie Bauer Bronco 5.0L AOD Full length headers, no cats annoying Flowmasters
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68 Posts
My 86 has full length headers, no cats, & flowmasters with turn downs before the axles. The mufflers are just behind the center console & that rear seat floor gets hot. So I would second that clogged cat thought.
 

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my interior is gutted, floor rhinolined, shorty headers, no cats, one magnaflow..you can definitely feel heat on the passenger side but it's not overwhelming and pretty much just at the floor..
 

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If you can, disconnect the exhaust just before the cat, then test drive and see if you have more power, that will help confirm the cat being the issue. It will be a loud and stinky test drive. You may also remove the cat and shine a light through to check if its clogged. On some setups its sold as part of the downpipe from the manifold, and is a fairly large peice to buy. Not hard to replace but worth confirming its the culprit before dropping the $$$
 

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Addicted to Junk
85 Bronco, 309ci I6 w/4bbl, np435, 4" lift, 37" Irok NDs, 4.56 w/ Detroit Locker and tru trac
Joined
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12,366 Posts
If you can, disconnect the exhaust just before the cat, then test drive and see if you have more power, that will help confirm the cat being the issue. It will be a loud and stinky test drive. You may also remove the cat and shine a light through to check if its clogged. On some setups its sold as part of the downpipe from the manifold, and is a fairly large peice to buy. Not hard to replace but worth confirming its the culprit before dropping the $$$
Ditto. The cat is a 2 into one design. So to fix it, you need to merge the two down pipes, then add a new 3-way cat. Or buy the whole thing as a unit.

I'm running long tube headers, a cat, and single 3" exhaust. Interior is stripped and has a bedliner on the floor. It too gets a bit toasty, but like said, only on the floor.

If cost is an issue, you can pull the cat and y-pipe, cut the rest off, and bust out the catalyst honeycomb inside the cat, essentially leaving a hollow shell. Obviously this is not recommended, as you wont have a working catalytic converter anymore, but it is a short term fix. Then reinstall, and use a band clamp to attach it to the rest of the exhaust.
 
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