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When the truck was cold I was checking things under the hood today and noticed that the overflow tank was at the max mark but when looking in radiator I could see the the flow tubes were not full. Is this normal? Should I fill radiator till tubes are covered with antifreeze? Do I use the blue color antifreeze or will the green stuff do? Thanks for your replies.
 

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Radiator should be full. Head over to your parts store of choice and buy a gallon of the house brand universal pre-mixed anti-freeze. That way you know it's compatible with most anti-freeze in use today and it's already correctly mixed to a 50/50 ratio with distilled water.
 

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I've raised this same question with my service department. You're levels are correct and do not need additional antifreeze - according to my service department. I've put another 16K since then and things stay the same. Personally, I think the flues should be covered so you use 100% of the heat rejection capacity of the radiator. But if you add, it just overfills the reservoir.
 

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I've raised this same question with my service department. You're levels are correct and do not need additional antifreeze - according to my service department. I've put another 16K since then and things stay the same. Personally, I think the flues should be covered so you use 100% of the heat rejection capacity of the radiator. But if you add, it just overfills the reservoir.
My radiator is kept full and the overflow is also kept at least 2in. above the max line. This means no more heater core gurgling these trucks are known for.
 

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When you took the radiator cap off you drained coolant into the bottle.

With these trucks you have to forget about the old school cooling system with a pressure cap on the radiator and the overflow bottle. The cooling system on the '05 and up are more advanced then that now. What looks like the old school overflow bottle with the min and max marks is now a pressurized, flowing, part of the cooling system loop. Technically it is the de-gas bottle.
The radiator cap, it is not longer a pressure cap. It is just a straight cap. Just a rubber seal.
That line that looks like the overflow hose, is what vents the air bubbles into the de-gas bottle where they are separated from the coolant. On the bottom of the de-gas bottle is another line (that you can't see very well) that flows coolant back into the engine. So as the engine is running there should be a steady flow out of the top of the radiator and into the degas bottle then back into the engine. You really need the engine warmed up (thermostat open) and the engine at speed to get that to work completely.

So what happen with you? You took the radiator cap off. The coolant now seeks its own level. The air pressure is now equalized and the level in the bottle comes close to the radiator. The coolant drained out of the radiator into the bottle. Not through the little vent hose at the top of the radiator but through the line on the bottom of the de-gas bottle tied back into the engine. So the low radiator and high bottle water levels are not a problem of the vehicle, but operator error. If you had just looked at the bottle and not opened the radiator you would not have induced the air into the system and would not have this issue. Easy fix though. Put the cap on the radiator, go drive it. When it warms up at driving speed it will push the air bubble out. and the coolant in the de-gas bottle will top off the radiator. The level in the de-gas bottle will drop. When it cools off again, check only the coolant level in the de-gas bottle and don't remove the radiator cap anymore (unless you are doing a full drain and refill service).

Never remove the pressure cap on the de-gas bottle when hot. It is pressurized as part of the cooling system. Just like never remove a radiator cap on a hot engine on an old school cooling system.

The fact that the modern cooling system looks like an old school system is a big part of the confusion here. If the radiator cap were removed like many other new cooling systems you would have to use the de-gas bottle to heck and fill the cooling system. At least Nissan was thoughtful enough to put a cap on the radiator so doing a cooling system flush would be easier.
 

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Good explaination ~ altho dealer techs shud already know it. My truck came w/2qt deficit. Rad replaced twice for leaks and each time half gal short which is outside of its burp capture range. The level at the bottle read as spec'd but apparently too much to self correct. Brought it to the service writers attn ~ some hang onto old concepts.

Good candidate as a Sticky
 

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When you took the radiator cap off you drained coolant into the bottle.

With these trucks you have to forget about the old school cooling system with a pressure cap on the radiator and the overflow bottle. The cooling system on the '05 and up are more advanced then that now. What looks like the old school overflow bottle with the min and max marks is now a pressurized, flowing, part of the cooling system loop. Technically it is the de-gas bottle.
The radiator cap, it is not longer a pressure cap. It is just a straight cap. Just a rubber seal.
That line that looks like the overflow hose, is what vents the air bubbles into the de-gas bottle where they are separated from the coolant. On the bottom of the de-gas bottle is another line (that you can't see very well) that flows coolant back into the engine. So as the engine is running there should be a steady flow out of the top of the radiator and into the degas bottle then back into the engine. You really need the engine warmed up (thermostat open) and the engine at speed to get that to work completely.

So what happen with you? You took the radiator cap off. The coolant now seeks its own level. The air pressure is now equalized and the level in the bottle comes close to the radiator. The coolant drained out of the radiator into the bottle. Not through the little vent hose at the top of the radiator but through the line on the bottom of the de-gas bottle tied back into the engine. So the low radiator and high bottle water levels are not a problem of the vehicle, but operator error. If you had just looked at the bottle and not opened the radiator you would not have induced the air into the system and would not have this issue. Easy fix though. Put the cap on the radiator, go drive it. When it warms up at driving speed it will push the air bubble out. and the coolant in the de-gas bottle will top off the radiator. The level in the de-gas bottle will drop. When it cools off again, check only the coolant level in the de-gas bottle and don't remove the radiator cap anymore (unless you are doing a full drain and refill service).

Never remove the pressure cap on the de-gas bottle when hot. It is pressurized as part of the cooling system. Just like never remove a radiator cap on a hot engine on an old school cooling system.

The fact that the modern cooling system looks like an old school system is a big part of the confusion here. If the radiator cap were removed like many other new cooling systems you would have to use the de-gas bottle to heck and fill the cooling system. At least Nissan was thoughtful enough to put a cap on the radiator so doing a cooling system flush would be easier.

^^ All this is correct.^^

I opened my radiator when the truck had around 4k on it ,and was shocked to see the radiator appeared empty. It took awhile but I eventually got an answer similar to this one.
 

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Radiator down 1 gallon of antifreeze. Heater core gurgling. Engine making a lot of noise on cold start. Service tech added one gallon and bled the system. After getting truck and returning home, antifreeze all over engine compartment and fender.

Brought back to dealer and told service rep that there was blue radiator fluid all over engine compartment. He told me that it couldn't be antifreeze and that it was windshield fluid since it was blue. I told him that Nissan uses blue antifreeze. He still didn't believe me. He opened up the hood and still tried to tell me it was windshield fluid. I told him to open the overflow tank. To his surprise, it was blue.He took the truck and detailed the engine compartment. 1200 miles on a 2013 KC SV.made in Mississippi.
 

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Radiator down 1 gallon of antifreeze. Heater core gurgling. Engine making a lot of noise on cold start. Service tech added one gallon and bled the system. After getting truck and returning home, antifreeze all over engine compartment and fender.

Brought back to dealer and told service rep that there was blue radiator fluid all over engine compartment. He told me that it couldn't be antifreeze and that it was windshield fluid since it was blue. I told him that Nissan uses blue antifreeze. He still didn't believe me. He opened up the hood and still tried to tell me it was windshield fluid. I told him to open the overflow tank. To his surprise, it was blue.He took the truck and detailed the engine compartment. 1200 miles on a 2013 KC SV.made in Mississippi.
He's too STUPID to hold his job. They started putting the blue long life anti freeze in the Frontiers in 2010. He's obvioulsly not aware of the products he services.

Clint
 

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The fact that the modern cooling system looks like an old school system is a big part of the confusion here. If the radiator cap were removed like many other new cooling systems you would have to use the de-gas bottle to heck and fill the cooling system. At least Nissan was thoughtful enough to put a cap on the radiator so doing a cooling system flush would be easier.
My apologies for posting to an old thread, but I have a related question concerning my 2010 Frontier. My Min and Max levels on the overflow tank (de-gas bottle) seem to function the exact opposite of the way I think they should. When the engine is hot, the coolant level is at the Min line. When the engine cools the level moves up to the Max line. Is this the way it is supposed to operate on this type of cooling system?
 

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An air bubble is a bolus of gas that expands upon heating and contracts when cooled. The level in the overflow tank would be opposite of what you observed.

Although improbable, it is possible for the air bubble to be expelled when the radiator is hot lowering the level. Upon cooling with no water in the overflow tank, the radiator will suck in air to re-form the bubble.

When the engine is dead cold what is the level in the radiator?
 

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So... silly question, the caps are on the correct way around?
I keep seeing these type of posts so I guess air pockets must be common. Personally I have never had a problem, changed my coolant out this summer, it took a couple top offs to completely fill the radiator, but thats it. There is no air in the radiator.
 

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An air bubble is a bolus of gas that expands upon heating and contracts when cooled. The level in the overflow tank would be opposite of what you observed.

Although improbable, it is possible for the air bubble to be expelled when the radiator is hot lowering the level. Upon cooling with no water in the overflow tank, the radiator will suck in air to re-form the bubble.

When the engine is dead cold what is the level in the radiator?
When the engine is cold, there is no coolant visible in the top of the radiator when you remove the "seal cap".
 

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So... silly question, the caps are on the correct way around?
I keep seeing these type of posts so I guess air pockets must be common. Personally I have never had a problem, changed my coolant out this summer, it took a couple top offs to completely fill the radiator, but thats it. There is no air in the radiator.
Yes, the spring cap is on the de-gas bottle and the seal cap is on the radiator.
 

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When the engine is cold, there is no coolant visible in the top of the radiator when you remove the "seal cap".
If the radiator is not full when dead cold, it should be filled with radiator fluid (not just water). It still does not explain the behavior of the level in your overflow tank. See if there is a kink in the line.
 

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If the radiator is not full when dead cold, it should be filled with radiator fluid (not just water). It still does not explain the behavior of the level in your overflow tank. See if there is a kink in the line.
I will top off the radiator and see if that corrects the issue. It will be tomorrow before I will be able to buy some coolant though. Thanks.
 

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I will top off the radiator and see if that corrects the issue. It will be tomorrow before I will be able to buy some coolant though. Thanks.
If I were to take mine off cold (and its cold outside) it would spill out a few tablespoons. Shouldn't be any air in there. I just did mine old school and ran it hot with the cap off and the heat on full blast. It kept dropping down as air came out until it eventually stopped and stayed full. I screwed on the cap and ran it a couple days, topped off the tank and been GTG ever since. Good luck man!
 

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If I were to take mine off cold (and its cold outside) it would spill out a few tablespoons. Shouldn't be any air in there. I just did mine old school and ran it hot with the cap off and the heat on full blast. It kept dropping down as air came out until it eventually stopped and stayed full. I screwed on the cap and ran it a couple days, topped off the tank and been GTG ever since. Good luck man!
When you say you ran it hot with the cap off, I assume you are talking about the pressure cap on the overflow tank / de-gas bottle?
 
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