When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Just did a coolant flush last month. Old coolant was Honda type 2 and new coolant was Honda type 2. Everything was fine but then when I did an oil change a few days later I noticed the coolant inlet hose for the oil cooler was bulging and looked ready to burst. So I bought a new hose and replaced it.
Now my problem is, when I did the air bleed for the coolant again, I noticed a few small yellow flakes in the coolant looking from the radiator and a lot of tiny smaller particles of indeterminable color floating around. Also when I was adding coolant with a funnel, some slight brown sludge made its way into the funnel and got stuck there. (The funnel was 100% clean before I began to use it). Are these particles and residue a sign of something bad? I looked at the old hose and funny enough there was a spot of yellow paint inside of it, but the pieces I saw in the coolant seem to be more than what would have come off of the hose.
I've seen those deposits before. Usually a sign that the coolant wasn't changed frequently enough in the past, it is a mix of corrosion and deposits. Doing additional flushes will get rid of more deposits in the cooling system , that is all you can do as you won't get all of it out on one flush. Leaving small amounts in the system won't hurt either, it is somewhat normal in older Hondas that may not have had fluid changed regularly.
the brown sludge is more concerning. Do you always use premix coolant or regular coolant mixed with distilled (not tap) water?
I used premix from my local Honda dealership. The guy didn’t ask me if I wanted concentrate so I kind of just assumed they didn’t have any. Saying that to myself I’m now realizing that may have been naive.
Originally Posted by zeroptzero
I've seen those deposits before. Usually a sign that the coolant wasn't changed frequently enough in the past, it is a mix of corrosion and deposits. Doing additional flushes will get rid of more deposits in the cooling system , that is all you can do as you won't get all of it out on one flush. Leaving small amounts in the system won't hurt either, it is somewhat normal in older Hondas that may not have had fluid changed regularly.
Yeah the cars approaching 140k miles, 5k of which I put on. Unfortunately it seems the previous owners didn’t do most of the necessary maintenance often enough besides oil changes. Thanks for the reply! That makes me feel better, I hope my water pump is fine.
edit: forgot to mention, before I did the first flush there was a lot of mold/mildew inside the overflow tank. Floating on the surface of the coolant and on the sides of the tank. Nasty.
I used premix from my local Honda dealership. The guy didn’t ask me if I wanted concentrate so I kind of just assumed they didn’t have any. Saying that to myself I’m now realizing that may have been naive.
Yeah the cars approaching 140k miles, 5k of which I put on. Unfortunately it seems the previous owners didn’t do most of the necessary maintenance often enough besides oil changes. Thanks for the reply! That makes me feel better, I hope my water pump is fine.
edit: forgot to mention, before I did the first flush there was a lot of mold/mildew inside the overflow tank. Floating on the surface of the coolant and on the sides of the tank. Nasty.
Yup guaranteed the previous owners did not change the coolant as recommended. Honda water pumps are pretty resilient, some of the rust colour you see comes from the pump as most of the system is aluminum. Sludge in the overflow tank is another sign the fluid wasn't changed. Some owners also use additives like Redline water wetter or similar products which react with Honda coolant to create sludge in the overflow tank, it percipitates and falls out of suspension in the tank during cooldown. Pre-mix Honda coolant is perfect.
Yup guaranteed the previous owners did not change the coolant as recommended. Honda water pumps are pretty resilient, some of the rust colour you see comes from the pump as most of the system is aluminum. Sludge in the overflow tank is another sign the fluid wasn't changed. Some owners also use additives like Redline water wetter or similar products which react with Honda coolant to create sludge in the overflow tank, it percipitates and falls out of suspension in the tank during cooldown. Pre-mix Honda coolant is perfect.
Thanks again. One reason I love Hondas, this car still runs and drives top notch even after being neglected.
I used premix from my local Honda dealership. The guy didn’t ask me if I wanted concentrate so I kind of just assumed they didn’t have any. Saying that to myself I’m now realizing that may have been naive.
Yeah the cars approaching 140k miles, 5k of which I put on. Unfortunately it seems the previous owners didn’t do most of the necessary maintenance often enough besides oil changes. Thanks for the reply! That makes me feel better, I hope my water pump is fine.
edit: forgot to mention, before I did the first flush there was a lot of mold/mildew inside the overflow tank. Floating on the surface of the coolant and on the sides of the tank. Nasty.
The mfgr coolant will almost always be premix (The honda stuff all is). If you buy aftermarket stuff like prestone, it will come in either premix or concentrated. Either is fine, as long as you know to use the right water with it to prevent putting mineral deposits in the system. Now there are some that say distilled is bad because while it removes impurities and deposit forming minerals, it creates a pH imbalance that can cause damage to some metals over time. This theoretically may be true, but I have had cars using distilled water in the coolant for 250,000 miles or more and have never in my life had any part of my cooling systems fail besides cracks in the radiator (plastic tanks) or hoses failing. I have had to replace one heater core in my life in my cars and it was full of sludge because the previous owner filled the radiator out of a garden hose I guess . Also, many shops use distilled water and have for decades. But to settle the minds of the purists on the topic, softened water is probably the better option to mix with according to some. BUT these days most of us just buy the premix coolant, whether it be from the dealership or the aftermarket premix stuff anyways. This is probably way more than you wanted to know in this thread since you used premix anyways... but I figured someone would swoop in with the "distilled water is terrible!"
The mfgr coolant will almost always be premix (The honda stuff all is). If you buy aftermarket stuff like prestone, it will come in either premix or concentrated. Either is fine, as long as you know to use the right water with it to prevent putting mineral deposits in the system. Now there are some that say distilled is bad because while it removes impurities and deposit forming minerals, it creates a pH imbalance that can cause damage to some metals over time. This theoretically may be true, but I have had cars using distilled water in the coolant for 250,000 miles or more and have never in my life had any part of my cooling systems fail besides cracks in the radiator (plastic tanks) or hoses failing. I have had to replace one heater core in my life in my cars and it was full of sludge because the previous owner filled the radiator out of a garden hose I guess . Also, many shops use distilled water and have for decades. But to settle the minds of the purists on the topic, softened water is probably the better option to mix with according to some. BUT these days most of us just buy the premix coolant, whether it be from the dealership or the aftermarket premix stuff anyways. This is probably way more than you wanted to know in this thread since you used premix anyways... but I figured someone would swoop in with the "distilled water is terrible!"
A lot of info indeed, but appreciated! I'm familiar with the aftermarket premixes and concentrates available as I have used them in previous vehicles of mine, but only OEM coolant will be going into my vehicles now. Worth the peace of mind since they are easily accessible and not much more expensive than aftermarket.
Honestly if I had to mix water I think I could probably get away with using my garden hose, lol. The tap water in my area is pretty low on calcium and sodium the last time I checked. (I used to maintain my pool's chemistry and once tested my tap water for fun).
04-21-2021, 02:14 PM
Yellow flakes in coolant
. Also, many shops use distilled water and have for decades. But to settle the minds of the purists on the topic, softened water is probably the better option to mix with according to some. BUT these days most of us just buy the premix coolant, whether it be from the dealership or the aftermarket premix stuff anyways. This is probably way more than you wanted to know in this thread since you used premix anyways... but I figured someone would swoop in with the "distilled water is terrible!" 
