Rx400h: Bubbles In The Coolant Reservoir

[Igino]

Hello everybody.

First of all, I want to say that I am very happy to join this nice community. I have browsed this forum for some time, founding here a lot of helpful information about the car that I just bought: a pre-owned, three year old Lexus RX400h with 85000 km (around 53000 miles) on its shoulders, no residual warranty.

The car is performing as expected, except for a detail that honestly is worrying me a lot: I noticed that, starting the car with the engine (ICE) cold, a lot of bubbles are perturbing the coolant in the reservoir. When the engine is warm, the coolant become quiet. However, when the engine is warm, and I check the coolant reservoir with the car (obviously) stopped, ICE is stopped as well...

Does somebody noticed the same thing in his vehicle?

Kind regards

Igino

[lemon]

I'm guessing you're talking about the coolant reservoir for the inverter. This is the one on the driver's side of the vehicle. The coolant reservoir for the engine radiator is attached to the back side of the radiator itself. Anyway, if you're talking about the inverter reservoir, it's totally normal for it to bubble like that.

If in fact you are talking about the engine coolant reservoir (back of the rad), then no it's not normal for it to bubble.

[Igino]

I'm guessing you're talking about the coolant reservoir for the inverter. This is the one on the driver's side of the vehicle. The coolant reservoir for the engine radiator is attached to the back side of the radiator itself. Anyway, if you're talking about the inverter reservoir, it's totally normal for it to bubble like that.

If in fact you are talking about the engine coolant reservoir (back of the rad), then no it's not normal for it to bubble.

Yes, it is on the driver's side, but I did not know that it was related to the inverter only ... so, its bubbling is normal? What a relief, I was really sick about that... Thanks a lot for the answer!

Cheers

Igino

[JeremyCZ]

Hi all, I'm new owner of RX400h, I have done timing belt and radiator change yet but now I suspect this thing in my invertor coolant when the car is on. It sounds like there is bleeding water but no leaking of water and it has still same amount of water. Is it normal? Thank you very much for your answers.

https://www.youtube.com/watch?v=a879lNNRcsA

[RX400h]

It seems like you never observed the coolant level before your radiator change. Is that correct? I'd have to say that I never have, either. I can take a look this weekend but keep in mind that there are quite a few different noises coming from a hybrid system, some of which can be heard with the hood closed but I suspect, also some that cannot be easily heard with the hood closed.