EazyLS460

A/c works fine and blows strong, but it’s getting colder outside now and when I turn on heat settings it blows out cold air while heat settings are on 85. No over heating at all haven’t changed or flushed out coolant since my purchase of car back in march 2022.

swfla

iTrader: (1)

Get trouble codes from OBD2. Some auto parts stores will do this for free. Lexus is $$$$.

Anfanger

Probably there is an air pocket in the cooling system or some of actuators are not functioning.

Boykie

My guess is enough coolant escaped via valley leak to create an air pocket.

Gerf

Is the coolant level low?? what's the temp gauge at ??

EazyLS460

Coolant is very low and temperature gauges operating at normal temps.

Gerf

Well, any sign of an external leak? I hope it's not the valley plate because that wont be much fun to repair.

Boykie

It is... Classic sequence of events. Also, ECT sensor is located top side. If coolant is low all it's picking up is air pocket temp. Danger.

swfla

iTrader: (1)

Besides looking for signs of coolant leak, you can try to bleed air from system to get the heater to work. There's a small plastic plug on top of a fitting, driver side, near radiator. It takes a hex key to open it while the car is running and warm. Turn on heater and add coolant to plastic coolant overflow. If air comes out and heater begins to work, you know there was air in system. Also the cap on overflow is supposed to hold pressure, it's cheap to replace. Like Boykie said, the valley plate leak scenario is a known issue as cars age. You didn't state age or mileage.

LS460Yeet

I had the exact same symptoms (heat wouldn't work, temperature gauges working normally, coolant low). I would inspect the radiator for any leaks. After driving my car and looking at the top of the radiator, I could see bubbling and leaking of radiator fluid so I just needed a radiator replacement. Lexus replaced my radiator for $1700 AUD. No problems since. You can also DIY this quite easily if this is the issue that you're facing.

EazyLS460

Heat working again just needed to top of coolant. During those hot summers I never wind down windows. Took a while to find the pink coolant online. Didn’t just wanna put any coolant in before doing some research and mess up radiator or water pump in long run. Thanks everyone for all the recommendations.

Anfanger

Did you track down the leak? Or you are just planning on topping off the system?

Boykie

Valley plate...

swfla

iTrader: (1)

Any leak is a bad thing as it will only get worse. Both suggestions of valley plate and radiator are very real possibilities. Now that your coolant tank is at the proper level, check it weekly. Then you can make an informed decision as to how quickly it goes down and when to do the repair. Keep an eye on the temperature gauge as well. This issue is far from over, it's going to get worse and may leave you stranded with an overheating engine and an unplanned(expensive) repair. Or even worse, you try to get home with an overheating engine and you destroy the engine in the process. What's the year and mileage of your car?

lwphat66

When you first bought the car back in March, was coolant at the proper level then? And if so, have you been monitoring the level throughout the summer?