Heater Not working

[Fohhunnid]

Ls400 with A/C issue, blows cold air when set to 80 degrees for heat.

I think it might be the coolant that is wrong or maybe bubbles in the pipes, but it just wanted to make sure i go about it the right way if someone else has had this issue.

Any help would be appreciated!

[chc0318]

As for my experience, it might caused by your COOLANT THERMOSTAT.

[RX400h]

First check your coolant level in the expansion tank and add Toyota coolant if necessary.

[Fohhunnid]

2 hours ago, chc0318 said:

As for my experience, it might caused by your COOLANT THERMOSTAT.

I remember the previous owner saying they replaced that prior to my purchase, so it might be something else

[Fohhunnid]

1 minute ago, RX400h said:

First check your coolant level in the expansion tank and add Toyota coolant if necessary.

I’ll check this out and see what i find!

[RX400h]

If the tank is full (to the indicated level line) then it could be that air in the coolant was not adequately bled when the thermostat was changed. If that is the case, then proper air bleeding must be performed. Many vehicle engines have one or more air bleed ports, as per the relevant service manual.

[paulo57509]

Check that the heater control valve located on the firewall is working.  When you adjust the temperature, the cable that's attached to the valve should move.

[Jeremy M.]

There's a bleed location just by the firewall at the top of the engine (at least on mine, I'm unsure about yours); pop the cap off of it and see if the fitting spurts fluid and no bubbles with the car running. If it has bubbles or no coolant comes out, bleed the air from the system. LS400s tend to like being bled parked on an incline (front end higher than the rear). My car also has bleeding instructions printed on the coolant reservoir, check yours and see if it details the procedure.

After that, check the heater control valve- it should remain closed until the engine nears or reaches operating temperature, and then the cable will open the valve. If the valve is broken, it's a fairly quick fix, but if the cable doesn't operate, you'll have a bigger issue, as the cable is either broken or the electronic controls are not operating.

If you need help locating either the bleeder or the valve, send a couple pictures / a video and I'll try and point them out. I'm more familiar with the 1UZ-FE VVT engine setup, as that's what's in my car, so if you happen to have the same engine, I can be more clear

[paulo57509]

I think that cap is actually a left over tap for some funky hot water defroster.

[Fohhunnid]

On 4/22/2022 at 1:35 PM, paulo57509 said:

I think that cap is actually a left over tap for some funky hot water defroster.

 

[Jeremy M.]

I've never seen the diagram for that water-heated windshield before; it explains why my filling procedure doesn't mention it though ¯\_(ツ)_/¯

As for the heater valve, I've gone and circled the valve in blue in your picture- on top of that, here's a picture of my reservoir sticker, since yours seems to have gone missing.

Take note of what position this arm on the side of the valve is in before and after your engine heats up. Mine is labeled, and yours may be as well- if it never opens from the "shut" position, take the cable off and manually open it. Follow the filling procedure first, and make sure not to skimp on time when holding the engine rpms up; those higher rpms are what's going to push the coolant through the heater core (keep your temperature controls set to max heat as well).

Lastly, if you still have no hot air coming through by the time you've completed the bleed procedure, and if your valve is being actuated by the cable, I would pull the valve out and physically check that it isn't broken; like any mechanical part, it can fail, but it is somewhat uncommon for them to go bad.