Recently im a new owner of a 1990 Bronco. She has a 5.8L 351 V8. The question i have if anyone is willing to give me some advice; I understand that alot of older model trucks need time to heat up, but the issue im having is that my heater doesnt blow very much hot air. Especially now that its super cold out I need to figure out how to get it to blow more hot air. Especially since i have three yard rats that ride with me i hate having them to bundle up more just because my heat is not "hot". Is this a heater core problem? Any tips and or advice is greatly appreciated!!! PS: Love the info on this tread!!!
As 87 advised...
Until we get more info;
More Heat; "...the 87-91 trucks with factory A/C have a recirculation door in their HVAC system, it's there to cut off outside air and keep running only in-cab air through the blower. It's vacuum controlled, and only cuts outside air when you put the control lever to off or max A/C. The problem I see with this is when you have 15F ambient temperature with some -20 windchill, heating up that air good could be a challenge for a truck with an aging heater core or tired blower fan. Last year just to see how much of difference it actually makes I zip-tied my recirculation door closed, thus running inside air through the HVAC system all winter long - things got real warm real quick, noticeable improvement even when truck is stationary. For the warmer days tho I want the recirculation door open so I can get fresh air in the cab as I drive... So I devised and implemented a solution in my 90 truck - I now have a manually controlled recirculation door that I can open and close to my liking, which means I can get tons of heat in the winter even with some nasty ambient temperatures..." http://fullsizebronco.com/forum/showthread.php?t=165079
Source: by M.L.S.C. at FSB
Poor Heater/Defroster Performance in Engine Coolant Concerns TSB 93-24-08 for 84-94 Bronco, F Series, Aerostar, Econoline & many others;
Insufficient heat inside of vehicles equipped with or without air conditioning may be caused by the heater air baffle missing from the plenum chamber. The heater air baffle prevents cold air from leaking in around the heater core.
ACTION: To correct this, check to see if the heater air baffle is present. If the heater air baffle is not present, install a heater air baffle using the following service procedure.
Heater Core Failure, Repeated TSB 01-15-06 for 85-96
Lack of Heat, Temperature Blend Door Cam Spring Does Not Blend Door to Seat Properly TSB 92-4-13 for Vehicles Built Prior to 11/11/91, 92 Bronco & F Series & F-47
ISSUE: Some vehicles may exhibit (repeat) heater core leaks. This may be caused by a chemical reaction called electrolysis. Electrolysis involves an ion exchange between the heater core and engine coolant which can result in a breakdown of the heater core material. This is similar to the operation of a battery.
ACTION: Check for electrolysis on any vehicle with a heater core failure. If electrolysis is verified, flush the coolant and follow additional steps as required. Refer to the following Service Procedure for details.
If there is a condition of a heater core leaking or repeat heater core leak, check for electrolysis using the following procedure:
To check for electrolysis use a DVOM set on DC volts. Place the positive probe of the meter in the engine coolant and the negative probe on the negative battery post.
Adjust engine throttle to 2000 RPM to properly get coolant flow and true electrolysis voltages.
If more than .4V is recorded, flush the
NOTE: EXPORT MARKETS, BE SURE THE WATER IS DESALINATED.
If there is still excessive voltage present in the coolant, check the engine body/battery grounds. Also, verify proper grounding of any aftermarket electrical/electronic equipment which has been installed into the vehicle. Improperly grounded electrical devices can cause electrolysis to occur.
If the condition is still present after the grounds have been checked, it may be necessary to add extra grounds to the heater core and engine. A hose clamp can be used to secure a 16 AWG stranded copper wire to the heater core inlet tube. The other end should be secured to an EXISTING FASTENER on the body sheet metal. Extra grounds to the engine should be attached between EXISTING FASTENERS on the engine and body sheet metal. Verify continuity of any added grounds to the negative battery terminal.
If the condition is still present, add a restrictor (part F1UZ-18D406-A) on the inlet hose with the arrow facing the direction of coolant flow (toward heater core). Cut the line and install with 2 hose clamps. It is important that the restrictor be installed in the right direction of flow and as close to the engine block as possible (not near the heater core itself.)
Coolant Fill Procedure
At times, in order to completely remove any trapped air in the cooling system of vehicles equipped with 4.6/5.4/6.8L modular engines, it may be necessary to use the following procedures:
Disconnect the heater hose at the right front or rear of the engine.
Remove the thermostat and housing.
Using the thermostat opening, carefully fill the engine with the proper clean coolant mixture until observed at the engine side heater hose connection.
Reconnect the heater hose and reinstall the thermostat and housing.
Fill the degas bottle to the coolant fill level mark.
Run the engine until it reaches normal operating temperatures.
Select max heat and max blower speed on the climate system.
NOTE: IF THE HEAT OUTPUT IS INSUFFICIENT, OR THE ENGINE DOES NOT REACH NORMAL OPERATING TEMPERATURES, VERIFY PROPER THERMOSTAT OPERATION AND REPEAT PROCEDURE IF REQUIRED.
PART NUMBER PART NAME
from 93 - 96 Ford Workshop Manuals; similar to your year;
Insufficient, Erratic, or No Heat or Defrost
Low radiator coolant level due to coolant leaks.
CHECK radiator cap pressure. REPLACE if below minimum pressure. FILL to specified coolant level. Pressure TEST for engine cooling system and heater system leaks. SERVICE as required.
REMOVE bugs, leaves, etc. from radiator or condenser fins.
CHECK for: Loose drive belt (8620)
Incorrect ignition timing
Water pump impeller damage
Restricted cooling system
SERVICE as required.
Loose drive belt.
REPLACE drive belt if cracked or worn and ADJUST belt tension.
FEEL heater water hoses (18472). If the heater water hoses are too hot to hold, the thermostat is OK. If the heater water hoses do not get too hot to hold, REPLACE the thermostat. If only one heater water hose gets hot while the other remains cool, a plugged heater water hose or a plugged heater core (18476) is indicated.
REFER to Group 03.
Plugged or partially plugged heater core.
CLEAN and BACKFLUSH engine cooling system and heater core.
Loose or improperly adjusted control cables.
ADJUST to specifications.
Kinked, clogged, collapsed, soft, swollen, or decomposed engine cooling system or heater system heater water hoses.
REPLACE damaged hoses and BACKFLUSH engine cooling system, then heater system, until all particles have been removed.
Blocked air inlet.
CHECK cowl air inlet for leaves, foreign material, etc. REMOVE as required. CHECK internal blower inlet screen (on vehicles so equipped) for leaves and foreign material. GO to Pinpoint Test F .
Blower Motor (18527) Does Not Operate Properly. Check Fuse
CONNECT a No. 10 gauge (or larger diameter) jumper wire directly from the positive battery terminal to the positive lead of the blower motor. If the blower motor runs, the concern must be external to the blower motor. If the blower motor will not run, connect a No. 10 gauge (or larger diameter) jumper wire from the ground lead to a good ground. If the blower motor runs, the trouble is in the ground circuit. On vehicles with ground side switching, CHECK the heater blower motor switch resistor (18591), the heater blower motor switch (18578) and the harness connections. SERVICE as required. If blower motor still will not run, the blower motor is inoperative and should be replaced.
Heater blower motor switch resistor.
CHECK continuity of resistors for opens or shorts with a self-powered test lamp. SERVICE or REPLACE as required.
Wire harness to blower motor.
CHECK for proper installation of harness connector terminal connectors. CHECK wire-to-terminal continuity. CHECK continuity of wires in harness for shorts, opens, abrasions, etc. SERVICE as required.
Heater blower motor switch.
CHECK heater blower motor switch for proper contact. REPLACE heater blower motor switch as required. GO toPinpoint Test C .
Loose or disconnected vacuum hose.
Damaged vacuum control motor (18A318).
Misrouted vacuum connections.
REPAIR or REPLACE system components as required.
Blend door operation, Check blend door for binding and proper operation; Mode door operation. Check mode door for binding and proper operation. Blower fan operation, Check blower fan for proper operation and control. Heater core plugged, Flush cooling system. Coolant level, Check level in radiator and coolant recovery reservoir. Leakage, Check for leaks using pressure test. Thermostat operation, Check Thermostat. Refer to "Thermostat Diagnosis" procedure.