Does Coolant Capacity Include Overflow Tank?

ssalvat

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Messages
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I did the flush this weekend. As usual it took longer than expected, and I'm second guessing myself on a couple of things, but that's typical for any job I do :)

In general it went fine. I drained the radiator and engine block, removed the thermostat, and pulled the heater core hoses to try to drain that too. All told I got barely over 1 gallon of coolant out, which was less than I had expected. Not sure where else it could have been hiding, maybe I didn't get a lot of what was in the core. Also weird, I'm still not sure what kind of coolant was in there. When I drained the radiator the coolant looked orange, so I figured Dexcool. But, when I drained the block through a clear hose it looked pink, like SLLC. When I drained the core into a clear measuring cup it looked pink, but when I poured it into a container it looked orange. Just depended on how the light hit it. Maybe it was originally pink and someone did a quick drain and refill with Dexcool so it was half and half, who knows.

Anyway, I filled the system up with distilled water and ran the car for a bit, then drained it, and what came out looked purple. When I held it up to the light it looked light pink, so again, a trick of the light and container it was in. I ended up filling and draining 4 times, after the last one the fluid was almost perfectly clear.

Since I was only able to get a gallon out I figured there must have been at least 2 quarts of distilled water left in the system after the last flush. When I refilled it I first added 2 quarts of Dexcool concentrate, then kept filling it up as air left with 50/50 Dexcool mix. Yes, I used Dexcool. I know a lot of people hate it, but I have another vehicle that takes it, and the fact that it comes in concentrate form let me get the right mix. Plus, from what I've read it sounds like the issue is letting air into the system with the Dexcool, and even then there were only a couple of engines that seemed really affected by it because of loose radiator caps, Dexcool by itself sounds fine.

I did have one scare when the heater wasn't working after I filled up, but I ended up going for a drive and it started back up. After I let everything cool down the level of coolant in the radiator and reservoir had both dropped, so I'm guessing just air in the core preventing fluid from moving through. I'm going to keep an eye on the coolant levels for a few days, and make sure the heater keeps working, and I still need to test the mixture to make sure I got the proportion right, but all in all I think it's good. Thanks everyone for the help!
 
Messages
60
I did the flush this weekend. As usual it took longer than expected, and I'm second guessing myself on a couple of things, but that's typical for any job I do :)

In general it went fine. I drained the radiator and engine block, removed the thermostat, and pulled the heater core hoses to try to drain that too. All told I got barely over 1 gallon of coolant out, which was less than I had expected. Not sure where else it could have been hiding, maybe I didn't get a lot of what was in the core. Also weird, I'm still not sure what kind of coolant was in there. When I drained the radiator the coolant looked orange, so I figured Dexcool. But, when I drained the block through a clear hose it looked pink, like SLLC. When I drained the core into a clear measuring cup it looked pink, but when I poured it into a container it looked orange. Just depended on how the light hit it. Maybe it was originally pink and someone did a quick drain and refill with Dexcool so it was half and half, who knows.

Anyway, I filled the system up with distilled water and ran the car for a bit, then drained it, and what came out looked purple. When I held it up to the light it looked light pink, so again, a trick of the light and container it was in. I ended up filling and draining 4 times, after the last one the fluid was almost perfectly clear.

Since I was only able to get a gallon out I figured there must have been at least 2 quarts of distilled water left in the system after the last flush. When I refilled it I first added 2 quarts of Dexcool concentrate, then kept filling it up as air left with 50/50 Dexcool mix. Yes, I used Dexcool. I know a lot of people hate it, but I have another vehicle that takes it, and the fact that it comes in concentrate form let me get the right mix. Plus, from what I've read it sounds like the issue is letting air into the system with the Dexcool, and even then there were only a couple of engines that seemed really affected by it because of loose radiator caps, Dexcool by itself sounds fine.

I did have one scare when the heater wasn't working after I filled up, but I ended up going for a drive and it started back up. After I let everything cool down the level of coolant in the radiator and reservoir had both dropped, so I'm guessing just air in the core preventing fluid from moving through. I'm going to keep an eye on the coolant levels for a few days, and make sure the heater keeps working, and I still need to test the mixture to make sure I got the proportion right, but all in all I think it's good. Thanks everyone for the help!
Use a refractometer to test the coolant level.
 

ssalvat

Thread starter
Messages
11
I bought a couple of cheap float type testers. I tested them on a known 50/50 coolant/water mix and both seemed to read accurately. I then tested the fluid in the radiator after a couple of 10 minute trips, one seemed to indicate I was a little under 50/50 and the other seemed to indicate I was a bit over 50/50. Either way well within acceptable range, and plenty of freeze protection. I'm going to retest in a week or two after giving things plenty of time to mix in there but feeling pretty good about it.
 
Overflow tank was a term Grampa used to use. For many vehicles, the expansion tank is now an active part of coolant circulation system and are now pressurized and coolant circulates through them and yes they are included in the volume. Rule of thumb? If it has a pressurized cap, assume it’s part of the total volume in the owners manual. My volume in my tank is about 1/2 a gallon.
 
Last edited:
A refractometer tests the coolant CONCENTRATION, not the level.
Level. Noun. Definition number 2.

ACC99F54-22CF-476C-A624-C5A5378FA866.png
 
I did the flush this weekend. As usual it took longer than expected, and I'm second guessing myself on a couple of things, but that's typical for any job I do :)

In general it went fine. I drained the radiator and engine block, removed the thermostat, and pulled the heater core hoses to try to drain that too. All told I got barely over 1 gallon of coolant out, which was less than I had expected. Not sure where else it could have been hiding, maybe I didn't get a lot of what was in the core. Also weird, I'm still not sure what kind of coolant was in there. When I drained the radiator the coolant looked orange, so I figured Dexcool. But, when I drained the block through a clear hose it looked pink, like SLLC. When I drained the core into a clear measuring cup it looked pink, but when I poured it into a container it looked orange. Just depended on how the light hit it. Maybe it was originally pink and someone did a quick drain and refill with Dexcool so it was half and half, who knows.

Anyway, I filled the system up with distilled water and ran the car for a bit, then drained it, and what came out looked purple. When I held it up to the light it looked light pink, so again, a trick of the light and container it was in. I ended up filling and draining 4 times, after the last one the fluid was almost perfectly clear.

Since I was only able to get a gallon out I figured there must have been at least 2 quarts of distilled water left in the system after the last flush. When I refilled it I first added 2 quarts of Dexcool concentrate, then kept filling it up as air left with 50/50 Dexcool mix. Yes, I used Dexcool. I know a lot of people hate it, but I have another vehicle that takes it, and the fact that it comes in concentrate form let me get the right mix. Plus, from what I've read it sounds like the issue is letting air into the system with the Dexcool, and even then there were only a couple of engines that seemed really affected by it because of loose radiator caps, Dexcool by itself sounds fine.

I did have one scare when the heater wasn't working after I filled up, but I ended up going for a drive and it started back up. After I let everything cool down the level of coolant in the radiator and reservoir had both dropped, so I'm guessing just air in the core preventing fluid from moving through. I'm going to keep an eye on the coolant levels for a few days, and make sure the heater keeps working, and I still need to test the mixture to make sure I got the proportion right, but all in all I think it's good. Thanks everyone for the help!
All seems well to me. I did some contributions to a thread about a year or two ago and pointed out Dexcool looks orange in an open container but looks pink when viewed through plastic, including a plastic expansion tank. Your observations on the coolant levels are right on the money.
 
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No point in making things more complicated than it has to be. For a fully flushed and drained system, divide the coolant capacity as stated in owners manual by 2 and add that amount of concentrated coolant to the system. Then top off with water up to the cold line on the on the bottle. Keep adding water as all the air is burped out. This always produces a 50/50 mixture. If its really cold where you are, reserve a bit of the coolant for topping off the expansion tank so it doesn't freeze before the system has a chance to burp some coolant back into it.
 
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