QuestionHi, I have just replaced the "el cheapo" Pep boys heater box I installed a month ago with the Ford brand at a significantly higher price. When I installed the cheap one, it worked for about 2 weeks, but we kept getting minute fog on the windows. I thought this was just residual in the system from the original bad one, but as time went on. The heavy steam from the vents came in and you could see under the hood, it leaking from the new hoses. I tightened those, but still steam. In need of advice, my local mechanic said the heater box was bad (at no charge of course). So' I replaced it last night. I let it warm up , it took the heat a while to kick in. I noticed there was a "valve" in line to the hose going in the driver side firewall heater core inlet (not sure if this is the in or outlet of the core) Is this the heater control valve? It took a long while for it ot open and allow the coolant to pass to the core. How much do these cost.
My car is a 94 merc sable 3.8 wagon LS.
Thanks for any advice.
AnswerHi Brian,
Here is a big TSB on this. This could explain why the dealer one is so much more expensive. As far as the heater control valve, this one does not have one. It does have a blend door actuator and motor. Internally, an electronic circuit accepts commands from the control head and positions the A/C air temperature control door by an electric motor. An integral potentiometer feeds the blend door position information back to the control head. I have a fairly good pic and detailed instructions. If you supply me with your email I will forward them to you.
Article No.
01-15-6
08/06/01
^ CLIMATE CONTROL - REPEAT HEATER CORE FAILURE
^ COOLING SYSTEM - REPEAT HEATER CORE FAILURE
FORD:
1985-1994 TEMPO
1985-1997 THUNDERBIRD
1985-2002 CROWN VICTORIA, ESCORT, MUSTANG
1986-2002 TAURUS
1988-1993 FESTIVA
1993-1997 PROBE
1994-1997 ASPIRE
1995-2000 CONTOUR
2000-2002 ESCORT ZX2, FOCUS
2002 THUNDERBIRD
1985-1990 BRONCO II
1985-1996 BRONCO
1985-1997 F-250 HD, F-350
1985-2002 ECONOLINE, F-150, RANGER
1986-1997 AEROSTAR
1988-1997 F SUPER DUTY
1991-2002 EXPLORER
1995-2002 WINDSTAR
1997-2002 EXPEDITION
1999-2002 SUPER DUTY F SERIES
2000-2002 EXCURSION
2001-2002 ESCAPE, EXPLORER SPORT TRAC, EXPLORER SPORT
LINCOLN:
1985-1992 MARK VII
1985-2002 CONTINENTAL, TOWN CAR
1993-1998 MARK VIII
2000-2002 GLS
1998-2002 NAVIGATOR
MERCURY:
1985-1994 TOPAZ
1985-1997 COUGAR
1985-2002 GRAND MARQUIS
1986-2002 SABLE
1991-1999 TRACER
1995-2000 MYSTIQUE
1999-2002 COUGAR
1993-2002 VILLAGER
1997-2001 MOUNTAINEER
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.
SERVICE PROCEDURE
Electrolysis Inspection
If there is a condition of a heater core leaking or repeal heater core leak, check for electrolysis using the following procedure:
1. 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.
2. Adjust engine throttle to 2000 RPM to properly get coolant flow and true electrolysis voltages.
3. If more than .4V is recorded, flush the coolant and recheck (follow guidelines in TSB 98-23-16 for Cougar). See Coolant Fill Procedure below to remove trapped air on 4.6/5.4/6.8L modular engines.
NOTE EXPORT MARKETS, BE SURE THE WATER IS DESALINATED.
4. If there is still excessive voltage present in the coolant, check the engine to 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.
5. 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.
6. 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 procedure:
1. Disconnect the heater hose at the right front or rear of the engine.
2. Remove the thermostat and housing.
3. Using the thermostat opening, carefully fill the engine with the proper clean coolant mixture until observed at the engine side heater hose connection.
4. Reconnect the heater hose and reinstall the thermostat and housing.
5. Fill the degas bottle to the coolant fill level mark.
6. Run the engine until it reaches normal operating temperatures.
7. 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.
Parts Block
OTHER APPLICABLE ARTICLES: 98-23-16
WARRANTY STATUS: INFORMATION ONLY
OASIS CODES: 208000, 208999, 402000
