Heater Leaking Heat When Off

[bamelanc]

Weird title I know…heater leaking heat.

When the heater lever is in the off position or in the vent position, warm air is still leaking out and warm days are made warmer due to this leakage.

Is this to be expected? Or do I have a leaking valve somewhere?

 

[3_puppies]

are the hoses getting warm?
the shutoff valve is not closing completely
follow the hoses in the engine bay and find the valve, either inline, on firewall or shutoff valve on head

pic of firewall valve in this thread:

Adding heater shut off valve

Hello, I want to add this heater core shut off valve for my 11/71. The original F motor had a manual shutoff valve on the driver's side head. I now have a 2F from an 87' 60s. I want to have the knob pull shutoff valve seen below from Genuine OEM NipponDenso TOYOTA Land Cruiser Valve Assy...

forum.ih8mud.com

 

[greenbeasty]

There is felt like something on the flapper thingie ( that term is in the FSM, look it up) inside the box. Probably needs a referb.

 

[73FJ40]

If there is heat in the heater, hot coolant is flowing through it. @3_puppies is correct, find the valve (if it's still there) and close it or replace it if it leaks.

The flapper has no effect on the flow of fluid to the heater core.

 

[Shark56]

Do you have a pull for the heat valve or do you shut it off at the head with a turn valve?

 

[Living in the Past]

Do you have a pull for the heat valve or do you shut it off at the head with a turn valve?

He lists a 74 which is the first model year for the valve operated from the dash. Manual valve on the cylinder heat ended 9/73. If heater is original to the vehicle and a vent on the top is should have valve operated from the dash.

 

[bamelanc]

He lists a 74 which is the first model year for the valve operated from the dash. Manual valve on the cylinder heat ended 9/73. If heater is original to the vehicle and a vent on the top is should have valve operated from the dash.

Yes, I have a fan pull, a fresh pull and a heat pull. Then a vent lever - Off, Vent, Heat.

With heat pull in closed position and vent lever closed. Heat can be felt emanating from the lower vent near the floorboard.

 

[pb4ugo]

It sounds like your heater control valve is letting hot water pass thru it to the heater core. With the 40 warmed up feel the pipes going to the heater and see if they're warm/hot. All this has been mentioned previously this thread. If the heat pull knob is in the off position, and the heater core is hot, then the valve is bad.

 

[bhsdriller]

Or the wire might not even be connected from pull knob to valve. That's how mine was and even with it connected I had to play with it to get it to shut/open properly

 

[flx]

Then a vent lever - Off, Vent, Heat.

If it's the stock lever it should be Vent, Heat, Def (for defrost), not Off.
Def being a variant of heat just routing the air differently.

Heat can be felt emanating from the lower vent near the floorboard.

Heated floorboard is a standard, non-deactivatable, feature of all FJ40s.
Are you sure the heat is leaking from the heater and not just the metal floorboard?

Be also sure that your shifters boots are all in good condition, burning air can comes from here (and if you have a PTO you lost the right to ever were shorts in the driver seat).
When driving for long enough, the metal floorboard can be so hot that the air close to the floor heats very quickly and it feels like a hot ventilation is on.
Foot doors vents are not here by mistake, they really help!

 

[cstav86]

I have an 11/1974 with a new valve and everything hooked up and mine does the same thing. When it warms up I'll pop the hood to make sure the valve is as closed as it can be.