Please help me understand cooling in Clarity.

A

alexsahka

Member
I know that the Clarity has two coolant radiators. I've seen conflicting information regarding the number of cooling systems, with some sources stating three and others two. I also found instructions on this forum for changing the engine coolant. My question is whether there is any information available on how to change the remaining coolants, and most importantly, how to bleed the system. I'm trying to perform these repairs myself as my Clarity approaches 100,000 miles. Any guidance would be greatly appreciated. Thanks!
 
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The Clarity manual lists 3 cooling systems, Engine, Inverter and HV Battery. All 3 use Honda Long Life Type 2 antifreeze/coolant with a recommended service life of 5 years or 60K miles. If yours was changed at the recommended interval it wouldn’t be due for another 20K miles. Was yours replaced at 60K miles?

My recollection is that the manual specifically states to have the inverter and battery coolant replaced by an authorized Honda service center. There could be a very good reason for that, but who knows?
 
Landshark said:
The Clarity manual lists 3 cooling systems, Engine, Inverter and HV Battery. All 3 use Honda Long Life Type 2 antifreeze/coolant with a recommended service life of 5 years or 60K miles. If yours was changed at the recommended interval it wouldn’t be due for another 20K miles. Was yours replaced at 60K miles?

My recollection is that the manual specifically states to have the inverter and battery coolant replaced by an authorized Honda service center. There could be a very good reason for that, but who knows?
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I'm the second owner and have no visibility on the complete maintenance history. I'm reading multiple sources recommending a coolant change at 120k miles or 10 years; is this incorrect?
 
I just looked at a half dozen online sites that sell the Honda product and they all state 5/60,000.

FWIW: I tended to follow the MM guidance on service with the Clarity. 5 is the signal for a coolant change.

alexsahka said:
I'm reading multiple sources recommending a coolant change at 120k miles or 10 years; is this incorrect?
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Landshark said:
I just looked at a half dozen online sites that sell the Honda product and they all state 5/60,000.

FWIW: I tended to follow the MM guidance on service with the Clarity. 5 is the signal for a coolant change.
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For some reason, I see the first change at 120,000 miles or 10 years, then every 60,000 miles or 5 years after that.

But this isn't the main question. I'm looking for how to change and bleed the HV system coolant.
 
The engine coolant is pretty straight forward to replace. But I looked at the process for the HV system and the fill/bleed process is a little complicated. I would be hesitant to do it myself.
 
Joe17 said:
The engine coolant is pretty straight forward to replace. But I looked at the process for the HV system and the fill/bleed process is a little complicated. I would be hesitant to do it myself.
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Contacted Honda Dealership; they quoted $1060 for HV system coolant change. This is ripoff
 
$1000 is a bit steep. I would think $300-400 would be more reasonable for the work involved. Maybe check with a shop that specializes in Honda, they may be able to do it as a lift seems like it's needed to get to the battery pack area.
 
alexsahka said:
For some reason, I see the first change at 120,000 miles or 10 years, then every 60,000 miles or 5 years after that.

But this isn't the main question. I'm looking for how to change and bleed the HV system coolant.
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We may both be correct depending on which internet facts we choose to believe. That’s the beauty of internet learning.

Either way, the service life intervals for coolant are almost always qualified as being “up to”, sort of like towing capacities for trucks. The recommendation is typically to begin checking (testing) the coolant at 50% of the maximum interval and change before the interval, if necessary.

It sounds like Joe17 may be able to provide you with instructions on how to change the coolant. His current recommendation is that the procedure may require an advanced skill set.
 
Joe17 said:
$1000 is a bit steep. I would think $300-400 would be more reasonable for the work involved. Maybe check with a shop that specializes in Honda, they may be able to do it as a lift seems like it's needed to get to the battery pack area.
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Do you have instructions on how to change the HV system coolant? My friend has a lift, and I am an engineer by trade. I've rarely needed a professional shop, aside from when I've had my windshield replaced.:)
 
Joe17 said:
$1000 is a bit steep. I would think $300-400 would be more reasonable for the work involved. Maybe check with a shop that specializes in Honda, they may be able to do it as a lift seems like it's needed to get to the battery pack area.
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Joe17, I was wondering if you have instructions for changing the HV system coolant that you could share? Thanks in advance!
 
FYI, there are two radiators and three coolant loops. The inverter & battery loops are separate, but run through the same radiator.
 
Man.. that's a lot of work! Based on the instruction, this can't be a DIY unless you have a way to turn on the pump to bleed air out.
 
I am somewhat confused about this thread. The maintenance service items in the Owners Manual only specify that the engine coolant need be replaced. The Inverter (DT) and the Battery (ES) coolants are not mentioned at all. Why would the DT and ES coolants need to be changed? I realize that the protective additives in the coolant can age out but I thought that the engine environment was much harser than that of the DT and ES cooling systems. Thus, the DT and ES coolant are "lifetime" fills. What am I missing here?
 
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leop said:
I am somewhat confused about this thread. The maintenance service items in the Owners Manual only specify that the engine coolant need be replaced. The Inverter (DT) and the Battery (ES) coolants are not mentioned at all. Why would the DT and ES coolants need to be changed? I realize that the protective additives in the coolant can age out but I thought that the engine environment was much harser than that of the DT and ES cooling systems. Thus, the DT and ES coolant are "lifetime" fills. What am I missing here?
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I'm also a bit confused. Honda calls their coolant "long life," lasting 10 years or 120,000 miles. I don't fully understand why you need to change engine coolant; I just did it because it wasn't difficult. The coolant was a very nice blue color with no discoloration—almost like new. My Clarity has 100,000 miles and mostly runs in EV mode, with only about 10,000-13,000 miles on the ICE.

I also have a Tesla Model 3, and Tesla doesn't require any service at all.
The temperature in EV components is very low, unlike in the engine, which runs close to 190°F.

There are many illogical things. Tesla is recommending no service at all (probably because of a lack of service centers). On the other hand, Honda calls for very frequent services to encourage dealership upselling.
 
leop said:
I am somewhat confused about this thread. The maintenance service items in the Owners Manual only specify that the engine coolant need be replaced. The Inverter (DT) and the Battery (ES) coolants are not mentioned at all. Why would the DT and ES coolants need to be changed? I realize that the protective additives in the coolant can age out but I thought that the engine environment was much harser than that of the DT and ES cooling systems. Thus, the DT and ES coolant are "lifetime" fills. What am I missing here?
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Here’s what you’re missing from the owners manual. There was also a link provided in this thread which shows 11 pages of specific instructions from Honda for replacing the coolant.

It seems peculiar to me that Honda would provide instructions for the procedure if the procedure was unnecessary. It could all be part of the upselling conspiracy, but an informed owner can simply say no to such practices. Honda also provides guidance on testing the coolant for proper concentration and recommends adding a concentrate if necessary.
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Honda recommend changine the engine coolant because of possible engine oil contamination. Engine oil and coolant do run next to each other in the engine and the engine coolant do get a lot hotter than the other 2.
 
Landshark said:
Here’s what you’re missing from the owners manual. There was also a link provided in this thread which shows 11 pages of specific instructions from Honda for replacing the coolant.

It seems peculiar to me that Honda would provide instructions for the procedure if the procedure was unnecessary. It could all be part of the upselling conspiracy, but an informed owner can simply say no to such practices. Honda also provides guidance on testing the coolant for proper concentration and recommends adding a concentrate if necessary.
View attachment 24327 View attachment 24328 View attachment 24329
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I was also thinking about this, and here are my thoughts.

Honda provided these instructions for a few reasons:
  1. The HV system exists and needs instructions on how to replace the coolant.

  2. Something happened to the HV coolant system, like the system started leaking or physical damage occurred to the coolant system.

  3. The HV battery needs to be changed.

  4. The car is very old or the mileage is high. (That's a good question: when does this condition happen?)
Furthermore, Honda's recommendation to test the coolant for proper concentration is based on prevailing weather conditions. For instance, a car operating in an Alaskan winter with very low temperatures would require coolant with a high concentration.

I just finished changing the engine coolant, and I have a feeling the instructions are incomplete or even written by someone other than Honda. The book is a ProDemand product, from a different company entirely. For example, based on my experience changing coolant, it doesn't recommend using a special funnel—a tool that is very helpful for purging air and adding coolant. Without this funnel, purging the air is very difficult.

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