Hello everyone, long time first time. Starting a thread is usually my last resort, and well here I am.
Battling a no heat issue on my 1998 Limited V6 2WD. More specifically, I'll occasionally get some lukewarm heat, but after running the fan for half a minute or so it'll go cold.
Background:
- Coolant gage always sits barely below the middle
- Scanner says coolant is reaching ~188F
- The heat has never worked since I've owned it
- The tees that go to/from the rear heater have been plugged
Attempts to solve:
- Brand new Spectra heater core
- Verified blend doors are working correctly
- Verified heater valve was working
- Bypassed heater valve
- New OEM thermostat
- 5-10 system bleeds
- New Radiator Cap
- Back flushed new heater core
- Back flushed engine/radiator
Here's the interesting thing. I replaced a section of hose before the heater valve with clear tubing and saw that with the truck running, the coolant is just sitting there; virtually no flow into the heater core.
Also, the system is not building pressure. After running and getting up to operating temp, you can pull the radiator cap off (even the new one) with no problem.
Am I missing anything? I'm pulling my hair out.