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Question Is flushing the radiator with a 1:1 mix of distilled water and distilled vinegar before adding new coolant a good idea?

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I'm about to replace my coolant and I'm curious if I should drain what's in it and just replace it per the service manual, or should I drain the old stuff, then do a full "flush" with 50/50 distilled water & vinegar, and THEN add the new coolant? My bike is getting up there in miles (60,000+) and I'm not exactly sure what brand of coolant the previous owner used so just for peace of mind I'm thinking I should do the water/vinegar mix first, but I'm not sure if it's necessary. What do you think?
 
If you put vinegar in it, how will you ensure you removed all the vinegar? If you have perhaps rinsed it thoughly with water after the vinegar, how do you know how much water might still be present in the system before you add coolant?

That seems like a lot of extra work. Don’t overthink it. Just drain the radiator and the block, and add fresh 50/50 coolant.
 
If you put vinegar in it, how will you ensure you removed all the vinegar? If you have perhaps rinsed it thoughly with water after the vinegar, how do you know how much water might still be present in the system before you add coolant?

That seems like a lot of extra work. Don’t overthink it. Just drain the radiator and the block, and add fresh 50/50 coolant.
That would be the ideal way to do it, but even on the instructions of the coolant I bought (Engine Ice) it says to fully flush the system before using their coolant. Do you still recommend doing it that way even though it's part of their instructions?
 
The Honda will run forever on a regular phosphate & silicate free coolant changed when recommended. Engine Ice is twice the price on the shelf and must be changed at least twice as often as OEM type coolant. In my opinion it’s simply not necessary and the only reason for a vinegar/distilled water flush is due to Engine Ice instructions.
 
I'm about to replace my coolant and I'm curious if I should drain what's in it and just replace it per the service manual, or should I drain the old stuff, then do a full "flush" with 50/50 distilled water & vinegar, and THEN add the new coolant? My bike is getting up there in miles (60,000+) and I'm not exactly sure what brand of coolant the previous owner used so just for peace of mind I'm thinking I should do the water/vinegar mix first, but I'm not sure if it's necessary. What do you think?
That would be the ideal way to do it, but even on the instructions of the coolant I bought (Engine Ice) it says to fully flush the system before using their coolant. Do you still recommend doing it that way even though it's part of their instructions?
Since you didn’t specify, I originally made the assumption you were concerned about what coolant the previous owner installed, as you wanted to install the Honda recommended coolant (“replace it per the service manual”). That you want to use Engine Ice instead was important information that was omitted. I can offer no suggestion other than to follow Engine Ice instructions and deal with any consequences that may arise from using their product.
 
Quick update. I went ahead and drained the old coolant and did a flush with the distilled water. I ran the distilled water through the system until the radiator fan turned on. I then waited several minutes for the bike to cool down, and drained the distilled water. It was mostly clear with a hint of blue from the previous coolant, so I went ahead and poured in distilled water from the radiator cap and kept a close look at the draining water until it had no more hint of blue. Then I went ahead and poured in the new coolant and burped it several times until it settled, then I topped it off as needed and topped off the reserve tank. Overall pretty easy job, but I think when I replace it in the future I'll just go with the Honda coolant. The Engine Ice wasn't my preferred choice but it was all they had at the time.
 
Quick update. I went ahead and drained the old coolant and did a flush with the distilled water. I ran the distilled water through the system until the radiator fan turned on. I then waited several minutes for the bike to cool down, and drained the distilled water. It was mostly clear with a hint of blue from the previous coolant, so I went ahead and poured in distilled water from the radiator cap and kept a close look at the draining water until it had no more hint of blue. Then I went ahead and poured in the new coolant and burped it several times until it settled, then I topped it off as needed and topped off the reserve tank. Overall pretty easy job, but I think when I replace it in the future I'll just go with the Honda coolant. The Engine Ice wasn't my preferred choice but it was all they had at the time.
If you have difficulty finding the specified Honda brand coolant for the NC, it is also sold at Honda automobile dealerships in gallon containers. That may open up possibilities for places to buy it.
 
I know this thread is old but FWIW, you use vinegar if you want to clean out water deposits from the cooling system. If you are just wanting to flush out the old coolant then you don't need vinegar. In fact, as long as you are putting the same color coolant back in (in this case blue), you don't even need to flush all the old stuff out. If you are going to use a different color coolant then you may want to flush with water since mixing different types of coolants can cause them to gel.

Also, if you are using distilled water to flush your system you don't have to then worry about getting all of the water out. In warm climates, where they don't have to worry about freezing, it isn't uncommon for radiators to get topped off with water. Regular water will work in a pinch but due to it leaving behind calcium deposits you should use distilled when able.
 
I'm about to replace my coolant and I'm curious if I should drain what's in it and just replace it per the service manual, or should I drain the old stuff, then do a full "flush" with 50/50 distilled water & vinegar, and THEN add the new coolant? My bike is getting up there in miles (60,000+) and I'm not exactly sure what brand of coolant the previous owner used so just for peace of mind I'm thinking I should do the water/vinegar mix first, but I'm not sure if it's necessary. What do you think?
I would flush out the expansion tank too , its where all the gunk seem to settle in mine .. only use distilled water or expect waterpump leaks .
 
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