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Old Jan 20, 2019 | 09:35 PM
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Cab fluid leak

Hey Guys,

I am new to the forum and just started getting into the truck. My mechanical knowledge is subpar but youtube and forums like this will hopefully help improve on that. I took my 73 f100 for a spin today and parked it in the garage so my son and I could change the oil. When I got home to change the oil I noticed this in my cab. It didn't really have a smell. I attached some pictures of where it looks to be coming from but I am not sure.

*pictures in comments*

On a positive note changing the oil with my 7-year-old as my helper was a great dad moment!
 

Last edited by Joecleston; Jan 20, 2019 at 09:42 PM. Reason: added photos
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Old Jan 20, 2019 | 09:41 PM
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From: Alpine, Ca

 
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Old Jan 21, 2019 | 03:45 AM
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Welcome to FTE, as long as it did/does NOT smell like antifreeze/coolant, you are doing ok. Usually a heater core leaks in on the passenger side floor board.
 
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Old Jan 21, 2019 | 08:00 AM
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If you have snow or ice on your truck, and a rust hole in your firewall..it could very easily just be melt off. Baby Blue gets it if conditions are just right.

Check your firewall along that general area.
 
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Old Jan 21, 2019 | 09:10 AM
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If you're not running antifreeze in your radiator, a leaking heater core will smell kind of like the air in a tire.
With antifreeze, it will smell like pancake syrup...

Also check the pinch weld where the floor-pan/toe-board meets the firewall. There is seam sealer there which can fail.
Another possibility is that the water is coming from the ventilation system. I've seen (online) the plenum tanks develop rust holes.
And if you have AC, it could be condensation overflowing because of a clogged HVAC case drain (tube).
 
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Old Jan 21, 2019 | 12:01 PM
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Originally Posted by 77&79F250
Welcome to FTE, as long as it did/does NOT smell like antifreeze/coolant, you are doing ok. Usually a heater core leaks in on the passenger side floor board.
I saw that from another thread on here. I checked again this morning now that my nose is free of oil and grime, I'm pretty sure its antifreeze. I will have to start it up tonight and see if I can locate the leak.

Thanks for the feedback.
 
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Old Jan 21, 2019 | 12:02 PM
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No snow or ice in my neck of the woods, Southern California. Thanks for the reply!
 
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Old Jan 21, 2019 | 12:05 PM
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Thanks for the advice. Ill take a look tonight. After looking again this morning I'm pretty sure its antifreeze. Last night my nose was not on target. This morning I checked and there was no additional fluid but the residual from yesterday had a sweet smell.
 
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Old Jan 21, 2019 | 12:11 PM
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Does the truck have AC? If it's heater only, then it's not too bad of a job to do the heater core. But before getting a new heater core, inspect the heater hoses under the hood. It could be as simple as a hose with a pinhole leak, which just happens to be aimed at a spot where it can get into the cab.
 
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Old Jan 21, 2019 | 04:28 PM
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Originally Posted by meangreen92
Does the truck have AC? If it's heater only, then it's not too bad of a job to do the heater core. But before getting a new heater core, inspect the heater hoses under the hood. It could be as simple as a hose with a pinhole leak, which just happens to be aimed at a spot where it can get into the cab.
This is my control panel. I have no actual vents in the dash.


 
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Old Jan 21, 2019 | 04:47 PM
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Maybe a bit of help?
Removal and Installation of Heater Core Assembly
First, use zip lock bags to store screws and nut as you remove screws and nuts, this will help you keep things organize during removal and installation of hardware. Take pics, take pics,take pics.
Read instruction, before purchasing parts needed.
Parts need: 1 heater core, 2 gallons of antifreeze, 1 RTV silicone rubber or 1 weather strip adhesive, 1 heater fan motor (recommended), anti seize compound for radiator hoses.
  1. Loosen peacock onradiatorto drain the radiator fluid from the radiator. Use a container to store the radiator fluid (antifreeze). Tighten peacock when fluid has drained.
  2. Remove glove box door, 2 hinges, 2 screws per hinge, and the cable which attaches to the glove box door.
    Remove the black glove box behind the glove box door. (use a very short screw driver)
  3. Move glove box to the left side to access the lower vent door screws on passenger side of truck and remove screws to lower vent door. Remove the lower vent door, use a short and medium phillips screw driver.
  4. Now remove the black glove box, from the bottom, where the lower vent door was located.TAP THE EDGES OF THE GLOVE BOX HOLE (STAMPED IN DASH) THAT AREA CAN BE SHARP!
  5. Locate the heater cables from the heater core assembly (big black unit, mounted under the dash), it is easier to find if you move the selectors for the heat or vent and floor selections on the dash above the radio. At the end of cable, locate the one screw mounted to the heater core assembly, and with a short phillips screw driver, remove the screws at the end of the cables, remove heater cables and tie up and out of the way.
  6. Locate the floor heater vent, this is locate in the front center lower portion, inside the truck, and is mounted to the heater core assembly, below the ashtray. Remove the two clips with a set of pliers, Be careful not to break or chip the heater core assembly when removing these clips.
  7. On the inside of truck, on the heater core assembly, on the right side (passenger side), under the dash, locate and disconnect the wiring harness that mounts to the big black unit, tie wiring harness up and out of the way.
  8. In the engine compartment, locate the fan motor, remove the wiring harness and the screw for the ground wire, which attaches to the fan motor.
  9. Loosen and slide away the the two heater hose clamps mounted to the heater core, at right (passenger side) rear firewall, of the the engine compartment, in the engine compartment.
  10. Remove heater hoses from the heater core at the rear of the engine compartment. Sometimes it easier to slice the rubber heater hose mounted to the heater core with a utility blade, use a regular screw drive to pry the heater hose away from the heater core. Use a container to catch any radiator fluid (antifreeze) leaking from heater hoses.
  11. Loosen the three nuts under the engine compartment (they look like 3/8" bolt sticking out of the firewall with a nut mounted to it). One is located on the rear portion of the fire wall and is located behind the right valve cover on the fire wall, most of the time there is a ground wire attached to it, remove the nut to remove the ground wire, and remove the nut behind the ground wire. The other two is located near the fan motor on the fire wall. Remove the three nuts.
  12. The heater core assembly is ready for removal.
  13. From the inside of truck. Wiggle and remove the heater core assembly. Patience is a virtue. Have some rags nearby to soak up any radiator fluid which leaks in the vehicle.
  14. After heater assembly is removed, find a clean area to place the heater core assembly.
  15. Locate the heater core and remove the screws and bracket.
  16. Remove the heater core from the heater core assembly.
  17. Save the old heater core, you will need the rubber and foam attached to it.
  18. When purchasing your new heater core, take it with you to the automotive store, to match the old heater core with the new heater core.
  19. Place the rubbers and foams off the old heater core on to the new heater core. Use a weather strip adhesive or RTV silicone to attached it.
  20. Before placing the new heater core onto heater core assembly. Remove fan motor screws and remove fan motor. Rinse out heater core assembly with water. Use a cotton rag and bucket of water with Pinesol, to wash the inside and outside of heater control assembly.
    Wash and rinse to accomplish necessary results. Dry with a cloth.
  21. Optional and highly recommended. Take into consideration of replacing old fan motor with a new fan motor at this time, youmight not want to remove fan motor a year of so from now. If your new motor does not have a plug, make sure to wire it properly. Color matching do NOT always make it turn the correct direction. Test before hard install. A new motor does NOT come with a squirrel cage. Use your old one, held on motor shaft with allen screw. Long type allen wrench, down thru the fan blade gap.
  22. Installation of heater core and heater core assembly.Follow instructions from step 18 backward to step 7. (if rubber foam needs to be replaced on heater core, use the rubber insulating foam for pipes)
  23. On step 6, make sure heater cables are adjusted correctly. Then, follow step 5 to step 2.
  24. Fill radiator, as recommended on label on antifreeze bottle, with new antifreeze and water.
Check for leaks.
Note:
  1. Use anti seize compound for radiator hoses on installation of the hoses, as it will ease have to remove hoses later, if needed.
  2. Check the condition of heater hose, replace if necessary.
  3. Replace thermostat if necessary.
  4. Replace radiator hose(s) if necessary.
  5. Check for leaks on radiator, fix if necessary.
 
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Old Jan 21, 2019 | 08:04 PM
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And I love the gear and lightning bolt embossed on the floor mat! Did the '73s really still have that logo?
 
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Old Jan 21, 2019 | 11:23 PM
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Originally Posted by meangreen92
And I love the gear and lightning bolt embossed on the floor mat! Did the '73s really still have that logo?
I love it too. I have only seen that logo on older models and I don’t want to replace the rubber flooring because I’ll lose that logo. If I replace the cab rubber I’ll find a way to repurpose the logo.
 
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Old Jan 22, 2019 | 09:16 AM
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Your cowl drains may be plugged if it doesn't smell like antifreeze or oil.
 
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Old Jan 22, 2019 | 09:27 AM
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Run a garden hose turned on into your cowl with the mats off of the floor and look for any drips or rivulets of water.
 
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