2017 RAV4 interior heating problem

[ppvora]

All,
I own a 2017 Toyota RAV4 Hybrid SE model. Right now it has about 80,000 miles on it. I put on roughly 12,000 - 15,000 miles on it every year.

About two years ago, I discovered that despite the turning the temperature knob to 74F or 75F, the vent was blowing cold air into the interior. During the next service, I asked the dealer to check it out. They said, "It's a lack of refrigerant. We added refrigerant and it's working fine." They charged me about $140 for that. But, the heating was ok. I thought this was strange that lack of refrigerant in the system affects heating.

A year ago -- same thing. I think they did the same thing but this time they said, "Since we charged you last time and the problem reappeared, we're not going to charge you again." OK. Heating was ok after that.

However, this problem has reappeared. But, with a small variation: the heating works randomly. But only 1 in 10 times. The defrosting of the front windshield is also not working anymore.

Any thoughts on the causes? Does their refrigerant story make sense? Should I just return to the dealer? I'm ok driving in this cold weather only because my driver's seat is heated. Otherwise...it would be really uncomfortable.

Thanks a lot community members!
Best,
Premal

[shorod]

Did they say refrigerant, or did they maybe say "coolant?" Refrigerant is what is in the air conditioning system, coolant is what goes in the radiator and flows through the heater core. It's also known as "Antifreeze/Coolant" because it doesn't freeze in the winter and cools the engine. A low coolant level would make sense for a lack of cabin heat.

Regarding the defrosting of the front windshield, is air blowing onto the windshield it's just not very effective (probably because it's not getting hot) or are you not even getting air flow?

-Rod

[ppvora]

It might have been coolant.

For the defrosting, air is blowing through the vents pointed toward the windscreen but there is no effect whatsoever.

[shorod]

It sounds like the defroster isn't working because it's not getting hot then. Sure, the defroster will engage the A/C system to dry the air if the ambient air temperature is high enough, but assuming you're trying to defrost ice, it will require heat as well. Or, your heater core is leaking enough that the coolant leaking in the heater core is putting a film on the inside of your windshield.

Assuming the shop said or meant "coolant," if they've had to add coolant twice, you have a leak somewhere. Do you know if they performed a pressure test on the system to check for leaks? If it's not leaking in the engine compartment then it could be leaking onto the floor in the cabin or leaking into a cylinder and getting burned and exits through the exhaust.

-Rod

[ppvora]

Is it possible that the leak is so small that it takes a year for it affect the coolant level?

I know the burnt coolant isn't coming out of the exhaust because I know what that smells like and the color of the exhaust fumes would also change. I'm not seeing any coolant on the floor of my garage, so unlikely that the leak (if any) is large enough for that.

But, I'm going to check the coolant level and fill it up if low and check whether that fixes the heat/defrost problem. If it does, at least I know where to start.

I vaguely remember the dealer saying something about doing the pressure test -- in fact the $140 might've been the pressure test because topping off fluids for free is part of my service agreement.

[shorod]

It would definitely be a very slow leak if it takes a year for the level to get too low. That might even be too slow of a leak for a pressure test to indicate, and certainly too small to smell or see in the exhaust.

Regarding the level, with other makes of vehicles owners have found that the overflow tank needs to be slightly over the "full Cold" mark (when cold) to have consistent heat. If the level is below that, the vehicles may stop blowing hot air while sitting at a stop light, etc. So you may want to slightly overfill it even if the level still appears correct and monitor for a change in the heat performance.

-Rod

[aleekat]

Maybe a back flush of the heater core?

[ppvora]

Bought Toyota's pink colored coolant. The local automotive shop said "Better to get the coolant/antifreeze that Toyota recommends for hybrids." It was relatively pricey.

Put the car into "Maintenance mode" so that the internal combustion engine runs continuously. Turned up the fan all the way and the heat to high.

Car took about one half gallon of coolant. Voila! Heat inside!

Thanks a lot for the replies and the guidance. Much appreciated.

If there's anything to report in the future will definitely do so.

[shorod]

I'm glad to hear it sounds like you might have it mostly sorted out. It will be interesting to hear if it continues to work this time or if in another year it's a bit low again. Although if it takes a year to get too low, that's not much of a leak. Keep an eye open for leaks though.

Thank you for following up on what you found out!

-Rod