tj884Rdlx

hey all,

yesterday my front heater stopped blowing hot for about 10 minutes. it was hot at first, then i parked a while for dinner. when i restarted later the heat was cold. all settings were still in the same place. i fiddled with every control, no affect. so i turned on my rear seat heater. it was working fine, very hot. a few mins later, i tried the front heat again, and it's blowing hot no problem.

same exact scenario today. driving for a while, gauge reads at middle, turn on fan and no heat from front. sliding any control has no effect. i can feel the difference between recirc and fresh, and the fresh is definitely being cut off on recirc. i can feel the air switching thru the top, vent, and floor outlets. it's all cold. but the rear heater is blasting hot just fine. i shut it off, drive another 10 mins, turn the fan on again, and it's blowing hot.

when i got home, i visually checked that the temp control cable is actuating the heater valve on the firewall. i can see the cable slide; i can see it slide the lever, and i see the chrome bar move in and out of the off-white round side of the valve, probably about 3/4" of motion. i see no leakage at the heater valve junction where the four hoses come together.

i looked for a heater hose diagram in the FSM and couldn't find anything concerning the heater hoses. it's not in "cooling" or "air conditioning" and i didn't see it in "body" either. anyone know where it is?

i don't understand how the rear can be blowing hot and the front not be, intermittently. blockage in the hose? if it came unblocked last nite, why return today? if it's t-stat, how can one be hot and not the other?

i'm really confused on this one. anybody?

thanx in advance!
Tj

thedanned

Check your coolant level/bleed system. If low, an air pocket could be circulating causing intermittent hot/cold heater core.

tj884Rdlx

i will chk that tomorrow, thanx for the suggestion. i've been researching for the last two hrs on this, and so far i've seen people here say:

their older style metal heater valve is crap and to replace it with a black plastic version;
to pull the hoses at the firewall and back flush the heater core, or
to check the black cable by the passenger's left foot, because there's a second cable controlled by the temperature control slider.


i replaced this radiator two years ago, with t-stat, and haven't had a cooling problem since. heat has been working perfectly, front and back, even all these past couple mos. so it's really weird that it's intermittent now. unless it's this cable flap dealie. i've got some places to check tomorrow, but in the meantime, i sure am glad i've got a rear seat heater so i'm not freezing on the ride in tomorrow.

tj884Rdlx

shop tells me today #3 has no compression. don't know if it's related. can't understand it at all

abecedarian

At this point... fix the headgasket issue then worry about the heater.

tj884Rdlx

hey abe, you've already seen my other thread, zo yeah, this ia now a dead issue. Oh well! But it appears it's not the hg, it's rings.

I guess when the motor comes out i'll have easy access to flush the heater core! Haha ugh.