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My 2018 Clarity has 33000 miles but seldom runs in HV mode. How often should I change the coolant and or flush the radiator?
 

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My 2018 Clarity has 33000 miles but seldom runs in HV mode. How often should I change the coolant and or flush the radiator?
Isn't there a service schedule in the Owner's Manual? The vehicle also has a "Maintenance Minder" function that should show up on the DIC when necessary.
 

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Coolant is usually good for 5 years or 150,000 miles.
 

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Isn't there a service schedule in the Owner's Manual? The vehicle also has a "Maintenance Minder" function that should show up on the DIC when necessary.
The published service schedule is non-existent for the Clarity PHEV. Maintenance Minder is garbage because you really can't plan for it.
 

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I wish here was a guage or meter that would give me actual HV time.

okay thanks
Yup. An old-school hour meter tracking engine run-time would be just dandy. Such a thing has existed on industrial machinery for at least fifty years. There was one on the fork lift I drove when selling building material, in college.
 

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Discussion Starter · #7 ·
Yup. An old-school hour meter tracking engine run-time would be just dandy. Such a thing has existed on industrial machinery for at least fifty years. There was one on the fork lift I drove when selling building material, in college.
I’m afraid if I even had a hour meter I would not know how to hook it up.🤨
 

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I’m afraid if I even had a hour meter I would not know how to hook it up.🤨
I don't either, but I'd think there'd be a way to hook it up to a tach or spark signal. In old days, you could clamp an inductive pickup onto the coil output wire. Now, we've got per-cylinder coils, and the firing signal is a little harder to detect.

Here's one for less than ten bucks on Amazon. You wrap a conductor around a spark-plug wire, and you're good to go.


Here's a link to someone installing one on a 2018 Clarity PHEV. It requires you to wrap a conductor around one of the per-cylinder coils, which of course requires a little under-hood time. Seems really easy:


I just ordered a meter for myself.

Thanks for prompting me to do a little research on something else I can do to my Clarity in the coming days...:rolleyes:
 

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Discussion Starter · #9 ·
I don't either, but I'd think there'd be a way to hook it up to a tach or spark signal. In old days, you could clamp an inductive pickup onto the coil output wire. Now, we've got per-cylinder coils, and the firing signal is a little harder to detect.

Here's one for less than ten bucks on Amazon. You wrap a conductor around a spark-plug wire, and you're good to go.


Here's a link to someone installing one on a 2018 Clarity PHEV. It requires you to wrap a conductor around one of the per-cylinder coils, which of course requires a little under-hood time. Seems really easy:


I just ordered a meter for myself.

Thanks for prompting me to do a little research on something else I can do to my Clarity in the coming days...:rolleyes:
Me too. Just ordered mine. Great link. Thanks
 

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Isn't there a service schedule in the Owner's Manual? The vehicle also has a "Maintenance Minder" function that should show up on the DIC when necessary.
There is no service schedule, the owner's manual only refers us to the maintenance minder. Although for a few items they give some guidelines beyond the maintenance minder:

Oil change: "If a Maintenance Minder message does not appear more than 12 months after the display is reset, change the engine oil every year."

Engine air filter: "If you drive primarily in urban areas that have high concentrations of soot in the air from industry and from diesel-powered vehicles, replace the dust and pollen filter every 15,000 miles"

Transmission fluid: "Driving in mountainous areas at very low vehicle speeds results in higher transmission temperatures. This requires transmission fluid changes more frequently than recommended by the Maintenance Minder. If you regularly drive your vehicle under these conditions, have the transmission fluid changed every 47,500 miles or 3 years"

Huh? At low speeds the engine will just be generating electricity. It's not like the engine is under an actual load directly driving the wheels at low rpm. I'm pretty sure that direct drive is not used in the situation described. I wonder if this is legit or if this is just boilerplate text copied from Honda's other owner's manuals? If someone drives in these conditions I'm not saying to ignore this, I'm just saying that I wonder about it.

Nothing in the owner's manual about coolant change. However the Maintenance Minder intervals can be deciphered using the same OBD-II scanner and software that is used to get battery capacity. This was first researched by @Clarity_newbie last year. I put the links to those threads at the end of this post.

The engine coolant message will appear at the ten year anniversary of the car going into service. I just confirmed this on my car. As Clarity_newbie discovered the maintenance minder is based to the day on when the car was put into service. So the dealer apparently does something at purchase to set the maintenance minder "clock". For example I purchased my 2018 Touring on April 26, 2019. As of today my maintenance minder says that engine coolant should be changed in 2683 days. Using Excel to calculate the dates, the due date is 4/25/2029 which will be ten years to the day from when I bought it. Actually off by one day, but I am just dividing total days by 365 and not factoring in leap years.

Of course some people may decide to change their engine coolant sooner than ten years, I'm just telling you what you can expect from the maintenance minder.

As for the other maintenance items,

A: oil and filter interval is one year. But the A message will appear sooner if you drive more than about 6,000-7,000 miles since the last reset. Although that includes all miles driven including EV miles, which is why many of us ignore the A message and just change the oil once a year.

The last time the A message popped up on my screen was 3/20/2021. I had already changed my oil a few months prior so I just reset it. Currently it shows being due in 90 days, which is 3/20/2022, or exactly one year from when I reset it. I have only driven my Clarity about 4,000 miles since I did the reset, if I had driven more than that the A message probably would have popped up by now.

3: transmission fluid, interval is six years (4/26/2019 to 4/26/2025)

4: replace spark plugs. This one appears to be totally based on ICE mileage, based on Clarity_Newbie's research. Even though ICE miles are not available to us on the display, Clarity_Newbie says that as he has monitored the minder for #4 and #8 (engine air filter) they both seem to be based on ICE mileage, so clearly the computer is capable of tracking ICE miles, they just figure we don't have any interest in seeing it (yeah right).

5: engine coolant, interval is ten years

7: brake fluid, interval is three years (4/26/2019 to 4/27/2022). Some people have already started to get the brake fluid message, but there is a separate discussion about whether it really needs to be changed that often. If you are thinking about DYI brake fluid change be sure to look for threads in this and other forums about it because the old fashioned DYI methods aren't quite enough there is a little more to it.

8: engine air filter - based on ICE miles

Here is the previous discussion about the minder:


 

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There is no service schedule, the owner's manual only refers us to the maintenance minder. Although for a few items they give some guidelines beyond the maintenance minder:

Oil change: "If a Maintenance Minder message does not appear more than 12 months after the display is reset, change the engine oil every year."

Engine air filter: "If you drive primarily in urban areas that have high concentrations of soot in the air from industry and from diesel-powered vehicles, replace the dust and pollen filter every 15,000 miles"

Transmission fluid: "Driving in mountainous areas at very low vehicle speeds results in higher transmission temperatures. This requires transmission fluid changes more frequently than recommended by the Maintenance Minder. If you regularly drive your vehicle under these conditions, have the transmission fluid changed every 47,500 miles or 3 years"

Huh? At low speeds the engine will just be generating electricity. It's not like the engine is under an actual load directly driving the wheels at low rpm. I'm pretty sure that direct drive is not used in the situation described. I wonder if this is legit or if this is just boilerplate text copied from Honda's other owner's manuals? If someone drives in these conditions I'm not saying to ignore this, I'm just saying that I wonder about it.

Nothing in the owner's manual about coolant change. However the Maintenance Minder intervals can be deciphered using the same OBD-II scanner and software that is used to get battery capacity. This was first researched by @Clarity_newbie last year. I put the links to those threads at the end of this post.

The engine coolant message will appear at the ten year anniversary of the car going into service. I just confirmed this on my car. As Clarity_newbie discovered the maintenance minder is based to the day on when the car was put into service. So the dealer apparently does something at purchase to set the maintenance minder "clock". For example I purchased my 2018 Touring on April 26, 2019. As of today my maintenance minder says that engine coolant should be changed in 2683 days. Using Excel to calculate the dates, the due date is 4/25/2029 which will be ten years to the day from when I bought it. Actually off by one day, but I am just dividing total days by 365 and not factoring in leap years.

Of course some people will decide to change their engine coolant sooner than ten years, I'm just telling you what you can expect from the maintenance minder.

As for the other maintenance items,

A: oil and filter interval is one year. But the A message will appear sooner if you drive more than about 6,000-7,000 miles since the last reset. Although that includes all miles driven including EV miles, which is why many of us ignore the A message and just change the oil once a year.

The last time the A message popped up on my screen was 3/20/21. I had already changed my oil a few months prior so I just reset it. Currently it shows being due in 90 days, which is 3/20/22, or exactly one year from when I reset it. I have only driven my Clarity about 4,000 miles since I did the reset, if I had driven more than that the A message probably would have popped up by now.

3: transmission fluid, interval is six years (4/26/2019 to 4/26/2025)

4: replace spark plugs. This one appears to be totally based on ICE mileage, based on Clarity_Newbie's research. Even though ICE miles are not available to us on the display, Clarity_Newbie says that as he has monitored the minder for #4 and #8 (engine air filter) they both seem to be based on ICE mileage, so clearly the computer is capable of tracking ICE miles, they just figure we don't have any interest in seeing it (yeah right).

5: engine coolant, interval is ten years

7: brake fluid, interval is three years (4/26/2019 to 4/27/2022). Some people have already started to get the brake fluid message, but there is a separate discussion about whether it really needs to be changed that often. If you are thinking about DYI brake fluid change be sure to look for threads in this and other forums about it because the old fashioned DYI methods aren't quite enough there is a little more to it.

8: engine air filter - based on ICE miles

Here is the previous discussion about the minder:


THANK YOU!:D
 

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Discussion Starter · #12 ·
THANK YOU!:D
Great info. If only Honda had let us know in the manuals for owners. Hate guessing games when it comes to keep my car in shape! Thanks for the info. I’m getting the engine hour monitor just for grins.😁
 

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Great info. If only Honda had let us know in the manuals for owners. Hate guessing games when it comes to keep my car in shape! Thanks for the info. I’m getting the engine hour monitor just for grins.😁
I must believe that the intent is to keep owners in the dark, as far as maintenance is concerned. The more "mystery" that remains, the more the "wizards" in the Honda Service bay must be employed.

It's a feature, not a bug, if you're Honda.
 

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Discussion Starter · #14 ·
I must believe that the intent is to keep owners in the dark, as far as maintenance is concerned. The more "mystery" that remains, the more the "wizards" in the Honda Service bay must be employed.

It's a feature, not a bug, if you're Honda.
I agree 100 percent.
 

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I just installed the hour meter, as described above. Took about thirty minutes. Works great!
 

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For the engine air filter, I open and inspect mine every spring after the trees have stopped blooming. If it's clean I put it back in. if it's dirty I put it back in and order a new filter at Amazon to put in the following weekend. My Volt has 67,000 miles and is on the original engine air filter. The Clarity only has about 7,000 miles (total). I replace the cabin air filter every year, though.
 
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For the engine air filter, I open and inspect mine every spring after the trees have stopped blooming. If it's clean I put it back in. if it's dirty I put it back in and order a new filter at Amazon to put in the following weekend. My Volt has 67,000 miles and is on the original engine air filter. The Clarity only has about 7,000 miles (total). I replace the cabin air filter every year, though.
Imagine that...common sense approach.

Kudos.
 
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