No Heat

[Lexuses71]

What would cause my climate control to not generate any heat after setting temperature to 73 degrees and vent closed on recirculate?

Just started this 2 days ago. MY car is a 1998 LS400, 84K miles. Very well maintained. Car is not overheating. Just looking for ideas and comments, thanks.

[sha4000]

The first thing to come to mind is that your coolant level is too low so you should definitely check that before going any farther. When I have my heater on that low I really don't feel the heat so I keep it up around 80. If those suggestions don't help I would think that your thermostat is stuck in the open position and might think about changing it.

[Lexuses71]

Thank you, Sha4000. That makes perfect sense. I will certainly check the coolant level before going any further. And the Thermostat is likely overdue to be changed anyway. Fingers are crossed. Appreciate the feedback!

[landar]

And maybe check the heater valve position?

[Lexuses71]

Landar, can u elaborate on that some? What position should it be in to allow heat?

[billydpowell]

feel the hose and you will know

[Lexuses71]

Billy: Which hose? Bigger diameter hose on left or smaller on right (in your pic) ? And am I supposed to feel a lump or knot? Or what?

[landar]

I believe that all the way up is full heat. With the valve wide open, you should feel both hoses being very warm to hot. That indicates that coolant is flowing.

You might have to disconnect the cable to move the lever all the way up. That cable is controlled by an actuator and I suppose it is possible for that to be inoperable.

[Exhaustgases]

I'm not sure but if the actuators are vacuum controlled a leak in a hose could cause that valve not to be moved to. If low coolant there will likely be an air lock going on too. Air in the system will block the coolant flow.

[Lexuses71]

OK, thanks. Will give it a try.

[sha4000]

Let us know what you find. This is usually not a difficult issue to diagnose or solve. Everyone has given you great advice.

[Lexuses71]

Yes, they have and it is much appreciated.

[billydpowell]

sorry to be slow getting back, heat was what I was referring to, I didnt elaborate since you were questioning heat, my thoughts were the INLET would be hot, and the OUTLET (going to the heater core) would not be hot since you posted lack of heat.. and you could see the range of the lever and even see it operate as you change your dials, just go to HOT and back to COLD to see it operate..