85 Bronco 2 heater hastle

Tiny
85BRONCOII
  • MEMBER
  • 1985 FORD BRONCO
  • 100,000 MILES
I've changed my heater core and thermostat and still my heater won't blow anything but slightly warm air unless I rev it over 1500-2000 rpms then it blows very hot. What else could it possibly be? I've heard there's a heater control valve that goes bad on these but I don't know where that is located. I've also heard I may have a vaccum line disconnected, which one and where is it located?
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Monday, November 14th, 2011 AT 3:32 AM

4 Replies

Tiny
RASMATAZ
  • MEMBER
Check the heater control valve and air bleed door/actuator
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Monday, November 14th, 2011 AT 4:34 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
If there is a heater control valve, it will be on the supply line to the heater core (inline with the heater hose). Make sure you have all air bled from the system and the coolant is full. Next, losen the return hose from the heater core to make sure there are no air blocks. Finally, make sure the system is pressurizing and there are no leaks.
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Monday, November 14th, 2011 AT 5:52 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
I forgot to add. You mentioned a vacuum issue. There is a blend air door that determines the air temp entering the vehicle. It is near the heater core (under dash) and is operated by vacuum. Check to make sure there are no vacuum leaks and it is working properly. I think Raz mentioned that, but I wanted to add.
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Monday, November 14th, 2011 AT 5:53 AM
Tiny
CJ MEDEVAC
  • EXPERT
OK--I CAN GET A FEW DIAGRAMS (VERY FEW)

THEY SHOW 2 SYSTEMS:

"HEATER"

"MANUAL HVAC"

I NEED TO KNOW WHAT YOU HAVE

THIS DIAGRAM WAS LISTED UNDER "MANUAL HVAC"----IS IT EXACTLY WHAT YOU HAVE? (SEE DIAGRAM)

DO YOU HAVE ANY PINCHED/ CRIMPED HEATER HOSES?

ARE YOU SLAP FULL OF COOLANT?

IS YOUR THERMOSTAT INSTALLED UP-SIDE DOWN?

IF YOU CHANGED THE HEATER CORE. SURELY YOU WOULD HAVE SEEN A VALVE ON THE 2 LINES (COMING AND LEAVING THE CORE) IF THERE WAS ONE.

JUST FOR GIGGLES---NOTE/ MARK WHICH HOSE IS IN WHICH POSITION DISCONNECT BOTH HOSES TO THE CORE---BLOW IN EACH ONE (NO DRINKY!) ONE AT A TIME----ARE YOU BLOCKED FROM BLOWING? OR ARE YOU PUSHING FLUID BACK INTO THE ENGINE?

NEXT--LETS GET SHORT PIECE OF 1/2" COPPER TUBING---OR A 1/2" REPAIR COUPLING OR ANYTHING SIMILAR. CONNECT BOTH HOSES TOGETHER (THUS BYPASSING THE CORE). FIRE HIM UP! SEE IF THE HOSES GET WARM/ HOT NOW?

IF YOU ARE GETTING HOT NOW, LET ENGINE COOL---LET'S SWAP THE HOSES OPPOSITE FROM HOW THEY CAME OFF. RE-CONNECT TO THE CORE. CRANKY UP. RESULTS?

OK--LET'S SAY ALL OF THAT FAILED

LET'S MAKE A DIAGRAM OF WHERE THE HOSES ORIGINATE---WHERE THEY TRAVEL TO---DO THEY TEE OFF TO ANYTHING, BEFORE THEY GO TO THE CORE? ACCURATELY DRAW WHAT THEY DO---THEN SNAP A PIC AND POST IT.

I HAVE A '77 CJ 5---I HAVE MANY MODIFICATIONS ON THE HEATER LINES, I LEARNED I MUST INSTALL "FIXTURES" AS IF IT WERE A "STEAM" SYSTEM."FEED AND RETURN". THINGS DO NOT WORK IN A SERIES

I HAVE A HEATED INTAKE MANIFOLD---NEXT BACK IS FACTORY HEATER--FURTHER BACK IS MY HOMEMADE REMOTE HEATER

SEND BACK RESULTS

NEXT TO LAST PIC--TEE TOWARD YOU IS INTAKE HEATER

TO RIGHT IS THE FACTORY HEATER CORE IN THE FIREWALL

UNDER BATTERY IS GOING TO THE REMOTE EXTRA HEATER (SAHARA BREEZE)

LAST PIC--SAHARA BREEZE

THE MEDIC
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Monday, November 14th, 2011 AT 5:59 AM

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