2003 LC100 – No Heat, Coolant Refilled, HVAC Clicking

[jopaul]

Hi everyone, I have a 2003 Land Cruiser (100-series, 4.7L 2UZ-FE). It’s around –35°C outside. The cabin heat is not working (blows cold). The coolant reservoir was empty and I refilled the radiator, but there is still no heat. When changing HVAC modes (feet/defrost), I hear a ‘tuk-tuk/clicking’ sound, but there is no sound when set to face. Could someone please advise what the issue might be?

 

[mrkdwrds]

Could still be air in the system, when you filled the radiator did you burp it (a no-spill funnel makes this easy) while running heat on hi?

 

[jopaul]

Could still be air in the system, when you filled the radiator did you burp it (a no-spill funnel makes this easy) while running heat on hi?

I’ve been gently pressing the upper radiator hose while running the heater on max hot to help release trapped air and waited till the bubbles stopped

 

[mrkdwrds]

I’ve been gently pressing the upper radiator hose while running the heater on max hot to help release trapped air and waited till the bubbles stopped

Separate issue but do you know why the coolant was low in the first place? Worth keeping an eye on the reservoir and hoses/radiator for a bit to track down a potential leak.

Sounds like the system is burped but mine took a while to clear all bubbles from system after replacing radiator/hoses.

Could maybe be a clogged heater core? You could try to read temps of the hoses that go into it at the firewall behind the heater Ts to figure out if it’s getting hot coolant.

 

[jopaul]

Separate issue but do you know why the coolant was low in the first place? Worth keeping an eye on the reservoir and hoses/radiator for a bit to track down a potential leak.

Sounds like the system is burped but mine took a while to clear all bubbles from system after replacing radiator/hoses.

Could maybe be a clogged heater core? You could try to read temps of the hoses that go into it at the firewall behind the heater Ts to figure out if it’s getting hot coolant.

Separate issue but do you know why the coolant was low in the first place? Worth keeping an eye on the reservoir and hoses/radiator for a bit to track down a potential leak.

Sounds like the system is burped but mine took a while to clear all bubbles from system after replacing radiator/hoses.

Could maybe be a clogged heater core? You could try to read temps of the hoses that go into it at the firewall behind the heater Ts to figure out if it’s getting hot coolant.

Yes i ll do that. Does the 2003 Land Cruiser have a bleed screw, or is there an alternative method to remove air from the system?

 

[mrkdwrds]

Yes i ll do that. Does the 2003 Land Cruiser have a bleed screw, or is there an alternative method to remove air from the system?

This post has the factory service manual instructions for bleeding. Basically, run engine while giving it a bit of gas and with heat on, squeeze hoses, wait until coolant level stabilizes and it stops bubbling. Best to wait for thermostat to open which can take a little while, maybe 15 mins or so depending on ambient temps.

A no-spill funnel makes the whole process much easier.

 

[jopaul]

This post has the factory service manual instructions for bleeding. Basically, run engine while giving it a bit of gas and with heat on, squeeze hoses, wait until coolant level stabilizes and it stops bubbling. Best to wait for thermostat to open which can take a little while, maybe 15 mins or so depending on ambient temps.

A no-spill funnel makes the whole process much easier.

Thank you. Appreciate your help

 

[leveeguy]

Hi everyone, I have a 2003 Land Cruiser (100-series, 4.7L 2UZ-FE). It’s around –35°C outside. The cabin heat is not working (blows cold). The coolant reservoir was empty and I refilled the radiator, but there is still no heat. When changing HVAC modes (feet/defrost), I hear a ‘tuk-tuk/clicking’ sound, but there is no sound when set to face. Could someone please advise what the issue might be?

Your air mix servo is probably what's making that noise. It controls the hot/cold temperature for the ac system. It is located under dash on passenger side towards center of vehicle.

If refilling coolant doesn't remedy the issue, this may be what you investigate next.

Is your rear heat working?