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OK, this is my first question thank you all for helping everyone.
I am not a novice working on vehicles, been doing share tree stuff for 50yrs. But this one has me a bit confused and would appreciate input.
1992 F-150, 5.0, 2wd, custom, extended cab. In the Summer with a/c running it will run hot, but no a/c it runs cooler side of Normal.
In the winter, can't seem to get it to ever fully warm up and blow hot air, lukewarm at best. The system has been flushed, new thermostat (I think 185), full of coolant.
I want to think fan clutch for Summer, or thermostat, but does not seem to make sense when having the opposite issue in Winter. I will add above 35 degrees to 55ish the heat OK. But below that I drive 20 miles to work and it is never quite warm in the truck, like most vehicles by 5-8 miles driven on highway you are turning down the fan. I have fan and temp full throttle the entire way.
Ideas? Please
OK, this is my first question thank you all for helping everyone.
In the Summer with a/c running it will run hot, but no a/c it runs cooler side of Normal.
In the winter, can't seem to get it to ever fully warm up and blow hot air, lukewarm at best. The system has been flushed, new thermostat (I think 185), full of coolant.
I want to think fan clutch for Summer, or thermostat, but does not seem to make sense when having the opposite issue in Winter. I will add above 35 degrees to 55ish the heat OK. But below that I drive 20 miles to work and it is never quite warm in the truck.
My '92 F150 (351) did the same thing years ago, but I tackled everything at once, so I don't know which was the cause (and I didn't learn anything).
Regardless, three things come to mind:
1. Thermostat is too cool or opening too soon.
2. Air in the system. If you're low on coolant, the heater store gets "starved" for water (a leaky system will point this out real fast). Also, that da** upper hose routes "way the heck up there"/it's the highest point in the system, and it's hard to get all of the air out sometimes.
3. Heater controls. I don't recall if the controls (heater doors and water valve) are manual or vacuum operated, but either way, next time you think it should be hot, grab both heater hoses and check if there's a difference in temperature. Better if you have an IR device or thermocouple to get an accurate measurement.
With regards to these sounding opposite to you (your quote above), what I've underlined makes perfect sense to me. Your truck runs cool in the summer, and even cooler in the winter.
I think I first will change the thermostat as you had mentioned.
As far as air in system, i want to profess that i have eliminated that issue, but am not sure I could do that confidently and may need to spend a little more attention there.
I chased the not warming up problem on one of these trucks years back. I threw three or four thermostats at it. Tested them in water on the stove before and after install. Didn't fix the problem. System was full, etc, etc.
I installed and inline thermostat and problem solved. No idea why moving the thermostat 6" solved it.
With regard to overheating, your radiator is probably partially plugged with rust assuming it's decades old. I find that most old iron block vehicles fill up the tubes with rust starting from bottom to top over time.
+1 for getting rid of the Fail Safe (it's probably stuck open)
If not and you use an infrared thermometer on your upper radiator hose, and come up with over 190, your stat is okay
The heater core might be plugged up or otherwise not transferring heat like it should
Some of them flow coolant just fine, like they are not plugged up, but only work on half a core because the bottom gets full of rust
I would
Verify the outlet coolant temperature in the upper radiator hose before tearing the thermostat out again
They have those digital thermometers at Home Depot cheap, by the barbeque grills
^CLIMATE CONTROL - LACK OF HEATING OR COOLING PERFORMANCE - NEW TEMPERATURE DOOR CABLE ADJUSTMENT PROCEDURE - VEHICLES BUILT AFTER 4/1/91
^CLIMATE CONTROL - NEW TEMPERATURE DOOR CABLE, CAM AND HEATER CORE DESIGN - REMOVAL AND INSTALLATION PROCEDURE - VEHICLES BUILT AFTER 4/1/91
LIGHT TRUCK: 1991-93 BRONCO, F SUPER DUTY, F-150-350 SERIES
ISSUE: A lack of heating or cooling performance may occur because the new design temperature door cable is not properly adjusted.
ACTION: A new design temperature door cable adjustment/retaining clip, temperature control cam and heater core cover have been introduced. The new design allows the cable to be pre-adjusted before installation at the assembly plant. The new cam and cover allows a greater closing force to be generated by the cable. If a temperature door cable adjustment is required or replacement of the cable and its associated components are necessary, refer to the following procedure for service details.
NOTE: CHANGING THE THERMOSTAT WILL NOT INFLUENCE POOR HEATER PERFORMANCE WHICH RESULTS FROM THE PRESENCE OF THE CAM SPRING.
NEW CABLE, CAM AND COVER USAGE
1993 vehicles are built with the new cable, cam and cover. These components should be used to repair all 1992 vehicles when, after cable clip adjustment, the temperature blend door still does not close properly at the full cold and full heat positions.
On 1991 F-Series and Broncos built from April 1, 1991, the 1993 cam and cover can be used for repair of the temperature blend door condition. However, the 1993 cable CANNOT be used. The 1991 cable is unique and should be used along with the 1991 cam and cover.
ADJUSTMENT
1.Release the glove box to gain access to the adjustment clip.
2.Pull back on the white tab on the adjustment clip as shown in Figure 1.
3.With the tab held back, move the barrel that travels through the clip in the direction required to obtain the proper door seating.
a.Move the barrel one notch.
b.Make sure that the door seats in each direction of travel.
CAUTION: DO NOT MOVE THE BARREL MORE THAN TWO NOTCHES FROM THE CENTER POSITiON IN EITHER DIRECTION. MOVING THE BARREL MORE THAN TWO NOTCHES MAY RESULT IN BARREL DETACHMENT FROM THE CLIP DURING LATER OPERATION OF THE TEMPERATURE LEVER.
4.On 1991 vehicles built from April through August 1991, follow Steps 1, 2 and 3 above. However, in Step 3, if more than two (2) notches of travel are required, replace the temperature control cam (F3TZ-19788-A) and the heater core access cover (F3TZ-18B299-A).
a.After reattaching the cable and clip, make adjustments to the clip.
b.Verify that the temperature door closes at both ends of travel.
5.On 1992 vehicles, follow Steps 1, 2 and 3 on the previous page. However, in Step 3, if more than two (2) notches of travel are required, check for cable or cam binding. If there is no binding condition, replace the temperature control cable (F3TZ-18518-A), the temperature control cam (F3TZ-19788-A) and the heater core access cover (F3TZ-18B299-A).
a.After attaching the clip, make adjustments to the clip on the cable.
b.Verify that the temperature door closes at both ends of travel.
6.On 1993 vehicles in Step 3, if more than two (2) notches of travel are required, first check the temperature control cable and cam for binding.
a.Cam binding can be checked by detaching the cable from the cam and actuating the cam by hand. The cam should move freely.
b.If it is binding, adjust it to eliminate the binding.
c.Reattach the cable and verify that the temperature door closes at both ends of travel.
d.If the temperature door still does not close properly, the concern most likely is in the control assembly.
a.Detach the cable from the control assembly. Follow the procedure in the Service Manual.
b.Check the travel of the rack when the temperature control **** is rotated to the full cold position. The notch in the rack should stop at the bullet connector bracket when rotated to cold, Figure 2.
c.If it does not come within 1 mm or touch the bracket, replace the control assembly (F2TZ-19980-A).
d.Reattach the cable.
e.Make necessary adjustments to the adjustment clip.
f.Verify that the temperature door closes at both ends of door travel.
SERVICE PROCEDURE
REMOVAL
The adjustment clip is attached to a molded-in bracket located in the upper left hand area of the heater core cover. The clip is retained by two (2) tabs. Special service tool D91T-18532-A (Heater-A/C Temperature Cable Clip Remover) is required to depress the locking tabs in order to allow removal from the attaching bracket, Figure 3.
1.Release the glove box to gain access to the adjustment clip.
2.Position the removal tool over the bracket and clip as shown in Figure 3.
3.Align the opening in the removal tool with the retaining tabs which project through the bracket, and pull back firmly.
NOTE: WHEN PROPERLY ALIGNED AGAINST THE BRACKET, THE TOOL HANDLE WILL BE HORIZONTAL, BUT ANGLED SLIGHTLY DOWNWARD.
This will depress the locking tabs, but will not unhook the clip from the bracket.
4.While maintaining the pull on the tool, pull the clip away from the bracket with the free hand.
5.Examine the adjustment clip for damage during removal. If one or both tabs are broken or no longer spread away from the body of the clip, replace the clip (F1TZ-14A163-D). If the entire cable must be removed from the vehicle, proceed as follows:
6.Disengage the cable wire from the temperature door cam pin, Figure 4.
7.Refer to the Service Manual to remove the A/C-Heater Control Assembly. Disengage the cable connector and wire from the control assembly.
8.If the temperature door control cam is being replaced, it should be removed at this time, Figure 5.
9.If the heater core access cover is being replaced, it should be removed at this time, Figure 5.
INSTALLATION
1.Attach the new temperature door control cam (F3TZ-19788-A) if it is being replaced.
CAUTION: DO NOT OVER-TIGHTEN.
Minimum torque is 0.7 N-m and maximum is 1.7 N-m. Check for binding or too much movement effort and adjust if necessary.
2.Install the heater core access cover (F3TZ-18B299-A) if it is being replaced.
3.Install the A/C-Heater Control Assembly (F2TZ-19980-A) if it is being replaced. Refer to the Service Manual for the procedure.
4.On the adjustment clip at the cable end, move the barrel so that the red insert is on "center" and the red does not show from either end. Further adjustment is not normally required, but can be made after installation, if necessary.
5.Attach the cable to the control assembly if not already attached in Step 3. Attach the wire coil end to the temperature control cam. Be sure cable is under cable retainer as shown in Figure 4.
6.Align the adjustment clip with the opening in the molded-in bracket as shown in Figure 3.
7.Push the clip firmly into place and ensure that both tabs hold the clip to the bracket.
NOTE: AN AUDIBLE CLICK SHOULD BE HEARD WHEN ENGAGED.
8.Pull firmly on the clip to verify proper retention of the clip.
9.Rotate the temperature control to make sure the temperature door closes at both ends of travel.
PART NUMBERPART NAMECLASS
F1TZ-14A163-DCable ClipB F3TZ-19788-ATemperature Door CamC F3TZ-18B299-AHeater Core Access CoverC F3TZ-18518-ATemperature Control CableC F2TZ-19980-AControl AssemblyB
WARRANTY STATUS: Eligible Under Bumper To Bumper Warranty Coverage For 1992/93 Model Year Vehicles. Eligible For Basic Warranty Coverage For 1991 Model Year Vehicles
OPERATIONDESCRIPTIONTIME 930209AAdjust Temp Cable Only (All0.2 Hr. Vehicles) 930209BCheck And Adjust Temp0.7 Hr. Cable, Replace Access Cover And Control Cam (1991 F-Series, F Super Duty And Bronco) 930209CCheck And Adjust Temp1.0 Hr. Cable, Replace Access Cover, Temp Cable And Control Cam (1992 F-Series, F Super Duty And Bronco) 930209DCheck And Adjust Temp0.8 Hr. Cable, Check And Replace Control Assembly (1993 F-Series, F Super Duty And Bronco)
DEALER CODING BASIC PART NO.CONDITION CODE 1851807
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