RX450h: Difference between Engine Coolant vs. Hybrid coolant replacement
Thread Starter
Pit Crew
Joined: Jun 2003
Posts: 170
Likes: 6
From: Florida
RX450h: Difference between Engine Coolant vs. Hybrid coolant replacement
Good afternoon everyone,
I would like to know what the difference is between the Engine coolant replacement and the Hybrid coolant replacement? Based on what I have read, in my service manual, the engine coolant should be replaced at 100K but I'm not sure when the Hybrid coolant should be replaced? Along with what the hybrid coolant replacement actually entails. Based on my research, the hybrid coolant replacement requires the system to be flushed while the engine coolant replacement requires a drain and fill. Is this correct? Any assistance with these questions would be greatly appreciated. Thank you.
I would like to know what the difference is between the Engine coolant replacement and the Hybrid coolant replacement? Based on what I have read, in my service manual, the engine coolant should be replaced at 100K but I'm not sure when the Hybrid coolant should be replaced? Along with what the hybrid coolant replacement actually entails. Based on my research, the hybrid coolant replacement requires the system to be flushed while the engine coolant replacement requires a drain and fill. Is this correct? Any assistance with these questions would be greatly appreciated. Thank you.
10th Gear
Joined: Jun 2019
Posts: 12
Likes: 3
From: AZ
I've been told by a mechanic that specializes in Toyota hybrids that the hybrid coolant shouldn't ever need to be replaced, just occasionally check and top off. I assume it lives a much easier life circulating through electric parts instead of a combustion engine.
As for engine coolant, I haven't done that on my 450h yet as it's still too low miles, but I plan to just drain and fill unless it's particularly nasty.
As for engine coolant, I haven't done that on my 450h yet as it's still too low miles, but I plan to just drain and fill unless it's particularly nasty.
CL Community Team
Joined: May 2005
Posts: 7,179
Likes: 1,721
From: VA
I would not make such as assumption about a dealer service department. You may have to instruct them and pay extra to have the inverter coolant serviced when you replace the hybrid battery.
One hybrid maintenance item often overlooked is cleaning the ducts and blades of the hybrid battery cooling fan system. Apparently dust clogged cooling fans and ducts are a cause of battery overheating. Some models have a filter on the fan intake.
I recently cleaned them on my HS250h and once I removed the back seat the cooling fan plastic ducts were easily unbolted as was the fan (with help from an access port in the trunk for one bolt). Then I cleaned out all the dust etc. There are youtube videos with demonstrations and instructions, search Toyota or hybrid battery cooling fan cleaning or similar. The RX fan may be under the cargo floor or rear seat, I don't know.
https://www.youtube.com/results?sear...g+fan+service+
One hybrid maintenance item often overlooked is cleaning the ducts and blades of the hybrid battery cooling fan system. Apparently dust clogged cooling fans and ducts are a cause of battery overheating. Some models have a filter on the fan intake.
I recently cleaned them on my HS250h and once I removed the back seat the cooling fan plastic ducts were easily unbolted as was the fan (with help from an access port in the trunk for one bolt). Then I cleaned out all the dust etc. There are youtube videos with demonstrations and instructions, search Toyota or hybrid battery cooling fan cleaning or similar. The RX fan may be under the cargo floor or rear seat, I don't know.
https://www.youtube.com/results?sear...g+fan+service+
I would not make such as assumption about a dealer service department. You may have to instruct them and pay extra to have the inverter coolant serviced when you replace the hybrid battery.
One hybrid maintenance item often overlooked is cleaning the ducts and blades of the hybrid battery cooling fan system. Apparently dust clogged cooling fans and ducts are a cause of battery overheating. Some models have a filter on the fan intake.
I recently cleaned them on my HS250h and once I removed the back seat the cooling fan plastic ducts were easily unbolted as was the fan (with help from an access port in the trunk for one bolt). Then I cleaned out all the dust etc. There are youtube videos with demonstrations and instructions, search Toyota or hybrid battery cooling fan cleaning or similar. The RX fan may be under the cargo floor or rear seat, I don't know.
https://www.youtube.com/results?sear...g+fan+service+
One hybrid maintenance item often overlooked is cleaning the ducts and blades of the hybrid battery cooling fan system. Apparently dust clogged cooling fans and ducts are a cause of battery overheating. Some models have a filter on the fan intake.
I recently cleaned them on my HS250h and once I removed the back seat the cooling fan plastic ducts were easily unbolted as was the fan (with help from an access port in the trunk for one bolt). Then I cleaned out all the dust etc. There are youtube videos with demonstrations and instructions, search Toyota or hybrid battery cooling fan cleaning or similar. The RX fan may be under the cargo floor or rear seat, I don't know.
https://www.youtube.com/results?sear...g+fan+service+
Racer
Joined: Mar 2011
Posts: 1,817
Likes: 229
From: wa
Toyota Synergy Drive has 2 coolant circuits:
1. standard engine/heater core one
2. inverter cool;ant one. Same circuit is cooling both motor generators.
You can DIY engine coolant, nothing special there. But, according to Big T, you need TIS to replace inverter coolant, as you need to operate dedicated coolant pump. That said, one of hybrid owners at toyotanation, simply siphoned coolant out of expansion canister, refilled it, let it cycle through, and then replaced again few times. It is a small volume circuit, not that hard to do.
Just in case someone will need this:
https://www.toyotanation.com/threads...ement.1641946/
1. standard engine/heater core one
2. inverter cool;ant one. Same circuit is cooling both motor generators.
You can DIY engine coolant, nothing special there. But, according to Big T, you need TIS to replace inverter coolant, as you need to operate dedicated coolant pump. That said, one of hybrid owners at toyotanation, simply siphoned coolant out of expansion canister, refilled it, let it cycle through, and then replaced again few times. It is a small volume circuit, not that hard to do.
Just in case someone will need this:
https://www.toyotanation.com/threads...ement.1641946/
Last edited by ukrkoz; Feb 28, 2021 at 04:30 PM.
Trending Topics
Toyota Synergy Drive has 2 coolant circuits:
1. standard engine/heater core one
2. inverter cool;ant one. Same circuit is cooling both motor generators.
You can DIY engine coolant, nothing special there. But, according to Big T, you need TIS to replace inverter coolant, as you need to operate dedicated coolant pump. That said, one of hybrid owners at toyotanation, simply siphoned coolant out of expansion canister, refilled it, let it cycle through, and then replaced again few times. It is a small volume circuit, not that hard to do.
Just in case someone will need this:
https://www.toyotanation.com/threads...ement.1641946/
1. standard engine/heater core one
2. inverter cool;ant one. Same circuit is cooling both motor generators.
You can DIY engine coolant, nothing special there. But, according to Big T, you need TIS to replace inverter coolant, as you need to operate dedicated coolant pump. That said, one of hybrid owners at toyotanation, simply siphoned coolant out of expansion canister, refilled it, let it cycle through, and then replaced again few times. It is a small volume circuit, not that hard to do.
Just in case someone will need this:
https://www.toyotanation.com/threads...ement.1641946/
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Intermediate
Joined: Jan 2018
Posts: 360
Likes: 42
From: Victoria, Australia
My 2012 Lexus RX450h comes equipped with a handy pet **** for draining the coolant out of the hybrid cooling system.
Apologies, this picture is upside down:
Located near the front of the vehicle behind the front bumper. There is no need to siphon out the old coolant. Made the task of changing the coolant very straightforward.
Considering that this is a job which has such a long service interval, this is really some really nice engineering by Lexus/Toyota ease of maintaining the vehicle.
Apologies, this picture is upside down:
Located near the front of the vehicle behind the front bumper. There is no need to siphon out the old coolant. Made the task of changing the coolant very straightforward.
Considering that this is a job which has such a long service interval, this is really some really nice engineering by Lexus/Toyota ease of maintaining the vehicle.
Last edited by tempestv8; Sep 7, 2022 at 07:42 PM. Reason: Fixed picture size
CL Community Team
Joined: Apr 2001
Posts: 16,557
Likes: 1,385
From: Austin, TX
Bit of clarification:
Engine coolant ... Does not get contaminated by combustion. The coolant circuit is isolated and fully contained. Overflow, reservoir and heat exchanger [radiator], thermostat, channels in the engine block [to cool down the block and the engine oil], heat fuel intake, supply heat to cabin.
Invertor coolant ... Does not cool electric motors. It cools the device used to convert DC power to AC power.
Ideally water provides the best heat transfer, but it causes corrosion and freezes at 0-C,
Salim
Engine coolant ... Does not get contaminated by combustion. The coolant circuit is isolated and fully contained. Overflow, reservoir and heat exchanger [radiator], thermostat, channels in the engine block [to cool down the block and the engine oil], heat fuel intake, supply heat to cabin.
Invertor coolant ... Does not cool electric motors. It cools the device used to convert DC power to AC power.
Ideally water provides the best heat transfer, but it causes corrosion and freezes at 0-C,
Salim
Pit Crew
Joined: Nov 2018
Posts: 181
Likes: 36
From: CA
Found
this to be useful. BOTH the inverter and engine use the same coolant -- Toyota long-lasting genuine coolant. Also, Toyota/Lexus hybrids' engine coolant lasts up to 100K miles; while the inverter coolant lasts up to 150K.
The master mechanic in his video recommends to change a bit earlier than recommended mileage, because you don't want to leave the stuff too long in there that can cause leaks.
The master mechanic in his video recommends to change a bit earlier than recommended mileage, because you don't want to leave the stuff too long in there that can cause leaks.
Thread Starter
Pit Crew
Joined: Jun 2003
Posts: 170
Likes: 6
From: Florida
Cost of Inverter coolant replacement
Good afternoon everyone,
I would like to know what the difference is between the Engine coolant replacement and the Hybrid coolant replacement? Based on what I have read, in my service manual, the engine coolant should be replaced at 100K but I'm not sure when the Hybrid coolant should be replaced? Along with what the hybrid coolant replacement actually entails. Based on my research, the hybrid coolant replacement requires the system to be flushed while the engine coolant replacement requires a drain and fill. Is this correct? Any assistance with these questions would be greatly appreciated. Thank you.
I would like to know what the difference is between the Engine coolant replacement and the Hybrid coolant replacement? Based on what I have read, in my service manual, the engine coolant should be replaced at 100K but I'm not sure when the Hybrid coolant should be replaced? Along with what the hybrid coolant replacement actually entails. Based on my research, the hybrid coolant replacement requires the system to be flushed while the engine coolant replacement requires a drain and fill. Is this correct? Any assistance with these questions would be greatly appreciated. Thank you.
CL Community Team
Joined: Apr 2001
Posts: 16,557
Likes: 1,385
From: Austin, TX
It would take 1 gal jug of coolant [with left over] and 1/2hr to 1 hr labor. The job is definitely less than an hour but mechanics round up.
DIY skill level is 1 wrench.
Salim
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