Posting for a buddy's '88 4Runner.
Tried burping the system of air with truck pointing
up on incline, removed heater return hose couple times, tried backflushing with garden hose, rear heater works fine, head gasket fine.
Floor trap has warm air, defrost lukewarm at best,
rear heater piping hot!
What gives?
Thanks!
Hugh

'86 SR-5 Extra-cab 4 x 4, 2" BL, 33 x 12.5 x 15R M/T on 15 x 8 rockcrawlers ( 3 3/4" BS ), 22RE 5 sp , 4.88's Detroit True-Trac front, V6 open rear, 24 mm Sway-Away + Rancho 5000's, removed sway bar, no-rust south US bed, Ramsey 8000 winch