No heat
11-16-2017, 06:02 AM
#3
Mark
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01-26-2019, 08:40 PM
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Howdy!
I just got through fixing my "no cabin heat" issue on my '99 F150 4x4 5.4 triton, 180k miles. What a journey!
Short version: Water pump failure (impeller fins were actually gone - completely worn off!).
Long version: I bought the truck about a year ago at 150k miles and noticed that the heat was marginal at best - kinda faded in & out, based on if I was moving or not. No overheating issues. I did have a very small leak in the radiator, which ended up being part of why the truck operated normally with a bad water pump. I'd have to add coolant about once a month or so. From my limited old school vehicle maintenance knowledge, heat still worked even if there were small compromises to the cooling system.
So, first thing I replaced was the thermostat. Not the issue.
Then, I did a heater core flush (in both directions) and complete coolant system backflush. Needed it anyway, I figured. System wasn't really all that dirty but I figured I'd go after the easy stuff first. Tip: To avoid pulling off those hard-to-reach and hard-to-remove heater hoses with the duckbill-style stock heater core nipple clamps, I simply cut a flush tee into both heater hoses - they're both right there and easy to access. Just be sure to orient the flush kit connectors the right way when you hook up your garden hoses - they only flow one way. And, avoid spilling water onto your coil packs as this will cause a misfire on those cylinders. So system wasn't dirty & so not the issue.
Then, since the hot/cold temp is controlled by a blend door in the moving air part of the system inside the cabin and not a heater hose or an in-line coolant valve like a lot of cars typically, I went after the blend door. I took apart a bit of the dash underneath and checked the blend door and actuator. Both in good shape. They were moving freely, no broken parts, stripped or burned out motors, etc, so also not the issue. I noticed at this point that the heater core was not even warm even at normal op temp. Still no heat and now starting to fear having to take dash out to replace heater core - so glad I didn't! BTW not a fan of dremeling into the airbox behind the glovebox. It is legit but just not my style. Dash can be taken out by the home mechanic (thank you youtube!)
Here are what the remaining symptoms were that led me to suspect that the water pump was bad. I bounced these off my mechanic and he suggested I replace the water pump (I was pleasantly surprised that it was only about $40):
Symptom 1: Cooling system would barely build any pressure. I'd drive for an hour, temp gage normal, go out and crack open the coolant res cap and not even a hiss. Also, very little water (if any) and no pressure at the flush tees as well.
Symptom 2: Whenever I'd be sitting at a long stoplight, temp gage would run up to about 3/4 of the way to the red, causing me a little concern until I'd start moving again. It would then settle right back to it's normal op temp.
Symptom 3: Both heater hoses were completely cold, even at normal op temp. One or the other being hot could be a sign of a clogged core, but in my case both were "cold".
So, I took my mechanic's advice and replaced the water pump. Lo and behold, as I mentioned, impeller fins were totally worn away. From all indicators, it appeared to be a slow, "over a lot of time & miles kind-of worn out" (no metal chunks anywhere, etc). Pump was not leaking or wet, and shaft & bearing appeared to be in good shape. Based on the bit of fight it gave me to get it out of it's hole, I'm guessing it was the original. Overall, not a bad repair - took me about 2 hours to replace pump & radiator. Note: Fan clutch nut on this one was right-handed (not like my old straight 6's which were left
So there ya have it! Hope this helps somebody tear out a little less hair than I did. Gotta have my heat (born &raised in Milwaukee).
Peace,
Gery the tree guy
I just got through fixing my "no cabin heat" issue on my '99 F150 4x4 5.4 triton, 180k miles. What a journey!
Short version: Water pump failure (impeller fins were actually gone - completely worn off!).
Long version: I bought the truck about a year ago at 150k miles and noticed that the heat was marginal at best - kinda faded in & out, based on if I was moving or not. No overheating issues. I did have a very small leak in the radiator, which ended up being part of why the truck operated normally with a bad water pump. I'd have to add coolant about once a month or so. From my limited old school vehicle maintenance knowledge, heat still worked even if there were small compromises to the cooling system.
So, first thing I replaced was the thermostat. Not the issue.
Then, I did a heater core flush (in both directions) and complete coolant system backflush. Needed it anyway, I figured. System wasn't really all that dirty but I figured I'd go after the easy stuff first. Tip: To avoid pulling off those hard-to-reach and hard-to-remove heater hoses with the duckbill-style stock heater core nipple clamps, I simply cut a flush tee into both heater hoses - they're both right there and easy to access. Just be sure to orient the flush kit connectors the right way when you hook up your garden hoses - they only flow one way. And, avoid spilling water onto your coil packs as this will cause a misfire on those cylinders. So system wasn't dirty & so not the issue.
Then, since the hot/cold temp is controlled by a blend door in the moving air part of the system inside the cabin and not a heater hose or an in-line coolant valve like a lot of cars typically, I went after the blend door. I took apart a bit of the dash underneath and checked the blend door and actuator. Both in good shape. They were moving freely, no broken parts, stripped or burned out motors, etc, so also not the issue. I noticed at this point that the heater core was not even warm even at normal op temp. Still no heat and now starting to fear having to take dash out to replace heater core - so glad I didn't! BTW not a fan of dremeling into the airbox behind the glovebox. It is legit but just not my style. Dash can be taken out by the home mechanic (thank you youtube!)
Here are what the remaining symptoms were that led me to suspect that the water pump was bad. I bounced these off my mechanic and he suggested I replace the water pump (I was pleasantly surprised that it was only about $40):
Symptom 1: Cooling system would barely build any pressure. I'd drive for an hour, temp gage normal, go out and crack open the coolant res cap and not even a hiss. Also, very little water (if any) and no pressure at the flush tees as well.
Symptom 2: Whenever I'd be sitting at a long stoplight, temp gage would run up to about 3/4 of the way to the red, causing me a little concern until I'd start moving again. It would then settle right back to it's normal op temp.
Symptom 3: Both heater hoses were completely cold, even at normal op temp. One or the other being hot could be a sign of a clogged core, but in my case both were "cold".
So, I took my mechanic's advice and replaced the water pump. Lo and behold, as I mentioned, impeller fins were totally worn away. From all indicators, it appeared to be a slow, "over a lot of time & miles kind-of worn out" (no metal chunks anywhere, etc). Pump was not leaking or wet, and shaft & bearing appeared to be in good shape. Based on the bit of fight it gave me to get it out of it's hole, I'm guessing it was the original. Overall, not a bad repair - took me about 2 hours to replace pump & radiator. Note: Fan clutch nut on this one was right-handed (not like my old straight 6's which were left
So there ya have it! Hope this helps somebody tear out a little less hair than I did. Gotta have my heat (born &raised in Milwaukee).
Peace,
Gery the tree guy
