Both my engine and hybrid coolant are decreasing of my 2005 rx400h with 120k miles.
i noticed the radiator is not in the best situation at the bottom. So this radiator should be replaced.

I try to understand how it is working and in the below document I see it are separated cooling systems flowing trough one radiator. Is this also correct for the rx400h?

Pdf file

Reasoning is that both cooling systems are loosing coolant.

 

Nobody any experience on this topic?

 

How low is low ? When was the last time you checked both levels of coolant.
If you notice the radiator is defective, get it replaced asap, just keep an eye on the hybrid coolant level, but do check ALL hose connections looking for any pink powder around hose connections... use only Toyota Pink/Red coolant and do a flush, how old is the coolant , how often do you check fluids levels.... many questions.... has someone used non-toyota coolant., dont mix coolant brands due to different coolant formulations.... these are considerations to address

 

Thx. This is clear for me. My main question is, if the same radiator is used for the engine coolant circuit and the hybrid coolant circuit (like the pdf)? Or are the 2 seperate radiators?

 

They are separate. Both cooling systems use the same type of coolant. It’s not uncommon to have to replace a Toyota/Lexus ICE radiator every 8 or so years.

The ICE radiator P/N is 16041-20353.The inverter radiator is P/N G9010-48010.

 

I have actually replaced the radiator twice in my 2008 RX400h. they just dont hold up. One thought is if the radiator hoses get stiff from age they put more stress on the radiator, also the constant on and off of the engine. Make sure your upper strut motor mount is not broken also, as this allows more motor movement when cycling on starts.