2nd Gen Non-Engine/Transmission Heat/vacuum issue?!

[Beach]

I posted a question last year about this problem but never got around to finding the problem! My truck is an '01 and it only spit's out luke warm air. I flushed the heater core, both line's are hot, blower work's fine, heater core is hot to the touch, I believe the blending door is working, not sure how well. Could there be a vacuum problem and if so, what do I check, where and what are some symptom's of a vacuum leak. It's getting cold and I need to deal with this. I'm not going to try and get by this winter like I did last! Thank's

 

[Makensmoke]

I'm sure you've checked but I had the same problem and solved it by cleaning the crud from the fins on the heater core. It was extremely difficult getting in there and cleaning it without removing it, but it paid off as it heats the cab nicely now. I'm sure there is still some junk in there, but I had to get 100k worth out anyhow.

 

[T-Bone]

?,



When my vacuum check valve failed and oil got into the vacuum lines, the first thing I noticed was all I could get was defrost. I pulled the dash and got to the heater controls. Using a MityVac from Harbor Freight, I checked each line on the back of the controls. Sure enough, the vacuum actuator that controls the defrost/panel/floor was bad. It is located above the go fast pedal. Found one is a junk yard for $5 and was back in business.



As for the heat, I did have a bad thermostat. I could never get heat in the cab and the water temp never came up. I pulled the thermostat and it looked like this. I replace the thermostat and I now have HOT air coming into the cab.

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T-Bone



Here is a pic of checking the heater controls:

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[Beach]

Thank's, I'll try doing a vacuum check and maybe cleaning the heater core if it's not to much of a pain to take the dash apart. I already have the glove box and cup holder out, so that's a start. Thank's again!

 

[T-Bone]

Beach,



My symptoms of a vacuum leak were no panel or floor air. Only defrost. Sounds like you may be Ok here.



What does your water temp come up to? With a bad thermostat, I would only see 140 maybe.



If you do need to pull the dash, remove the cup holder and ashtray. Tilt the steering wheel down and move the gear shift lever into first. The dash bezel just pulls straight out. No screws. The heater controls are accessible then.



Good luck!

T-Bone

 

[Makensmoke]

I cleaned the core by pulling the fan and reaching in, I didn't pull the dash by any means. I did pull my front seat though so I could lay down to try and get up the duct and to the core though, it wasen't very easy, but had to be better than pulling the dash.