Just wondering if any of the Nissan guys on ExPo have had this problem. My 2012 Frontier SV 4x4 blows cold air when the RPMs drop to idle even with the engine at temp. Normally would think low fluid level first, but sitting level everything looks fine. But I've found a thread over on Club Frontier that talks about the system gathering air bubbles in the core and adding coolant to the top of the overflow tank will help purge the air from the system. Is this something any of you have dealt with? I can take it in to the shop but if the fix is that simple I would rather try at home.
Frontier heat blows cold at idle
- Thread starter fortel
- Start date
Airmapper
Inactive Member
Yeah I had that issue and did what you described on my Xterra. (all the same as a Frontier under the hood)
Just adding more coolant to the overflow tank helped, apparently it pulled enough into the system to get an air gap out. I did have to fill it over the "FULL" line, it claimed it was full but apparently it just needed a little bit more.
I've heard of some folks trying it and it not working, but it seems the majority of the time just adding more coolant to the overflow tank does the trick.
Just adding more coolant to the overflow tank helped, apparently it pulled enough into the system to get an air gap out. I did have to fill it over the "FULL" line, it claimed it was full but apparently it just needed a little bit more.
I've heard of some folks trying it and it not working, but it seems the majority of the time just adding more coolant to the overflow tank does the trick.
wreckdiver1321
Overlander
Mine had an issue where it blew cold just after the truck was started. I could idle it for 15 minutes and it would not blow warm air. If I got in it and revved the engine, then it would blow hot. No matter what RPM.
I let it cool down, then I added coolant to the overflow tank until it was about an inch and a half past the fill mark. I kept the cap off and let the truck idle for about 25 minutes, occasionally revving and occasionally holding the engine at 2000 RPM. The coolant level dropped a bit, so I filled it back to where I had it before. Then I drove on it for a while and it hasn't been an issue since.
I let it cool down, then I added coolant to the overflow tank until it was about an inch and a half past the fill mark. I kept the cap off and let the truck idle for about 25 minutes, occasionally revving and occasionally holding the engine at 2000 RPM. The coolant level dropped a bit, so I filled it back to where I had it before. Then I drove on it for a while and it hasn't been an issue since.
Ran by and picked up a gallon of Nissan coolant on the way home. Once it cools off I'll start adding to the overflow tank as described and see where it levels off. Some on other forums said they had to repeat a couple of times until the level quit dropping. Thanks for the replies, I'll post results once I see what happens.
Dmski
Adventurer
If this doesn't solve your problem, after you run the truck for 10 minutes or so turn it off, gently massage the top radiator tube to coax any air bubbles out and fill whatever is left over as necessary. May need to repeat. I've had the same issue on my truck. They seem to just want to have air bubbles after a coolant drain and fill...
So a couple of evenings ago I picked up a gallon of the Nissan coolant, let things cool down, and then filled the overflow tank to the top. Some on other forums mentioned parking with the nose up to help get any bubbles out - don't know if it matters or not but I did put the front on ramps while the engine was cooling off. I'm glad to report that yesterday and this morning with temps from single digits to low teens the heater is blowing heat again at idle. I'll check again this weekend to see how far the level dropped and can add more if needed but the one overfilling seems to have corrected the issue. I know others have said they had to repeat the step an extra time or two to get all the air out. What's funny is that I checked the level in the overflow tank a couple of times after the problem started knowing that low levels could cause the problem but the tank always showed correct levels when hot or cold. I wouldn't have expected the system could get enough air in it to cause the issue.
Don't over fill the tank.
Here's a "How to" from thenewx.org:
http://www.thenewx.org/forum/11-pow...oblems-if-heater-blows-cold-idle-no-heat.html
Here's a "How to" from thenewx.org:
http://www.thenewx.org/forum/11-pow...oblems-if-heater-blows-cold-idle-no-heat.html
broncobowsher
Adventurer
The heater core is the high point in the cooling system. Only takes a little air bubble to air lock the water flow through the heater and kill idle heater performance. The water ports in the engine are large enough that at idle the water pump can't push that air bubble out. Path of least resistance is the internal passages in the engine (priority coolant circulation).
Adding coolant does wonders. And it generally doesn't take much. Most of the ones I know of can be fixed with just a pint of water. Just enough to get up to the max mark. Out of dozens of these I have done I have never needed a fancy funnel, never needed a hill or ramps. But it has always taken a drive that got the engine to rev a bit so the water pump can blow that bubble out of the heater.
Adding coolant does wonders. And it generally doesn't take much. Most of the ones I know of can be fixed with just a pint of water. Just enough to get up to the max mark. Out of dozens of these I have done I have never needed a fancy funnel, never needed a hill or ramps. But it has always taken a drive that got the engine to rev a bit so the water pump can blow that bubble out of the heater.
sailorcolin
Observer
Whenever my coolant is low, the heater core runs dry, I have to make sure my coolant tank is topped off, otherwise, mine heat runs cold too.
My truck blows nice hot air but the other day I had it idling (warm) for a minute while I loaded something in the back and when I got back in the truck I thought the air blowing was a bit cool. Started driving and all become okay. Guess I need to try this trick of filling the overflow some.
broncobowsher
Adventurer
Not that much of a trick, a lot closer to general maintenance.
Hardly maintenance there bub. My coolant and all fluids get checked often and replaced when needed. Overfilling the overflow while the radiator is full is not maintenance.
broncobowsher
Adventurer
Learn your cooling system. That is NOT an overflow bottle. It is a degas bottle. It is pressurized and a part of the coolant flow. These truck do not have an overflow bottle. While running there is a steady flow of coolant (and air bubbles if any) off the top of the radiator. Removing the radiator cap makes for a huge air bubble that the system has to work to get out. If you noticed the radiator cap is just that, a cap. There is no pressure rating and nothing to block the flow out of the top of the radiator to the degas bottle. It is a bit hidden but on the bottom of the degas bottle there is a hose going back to the engine. This is where the coolant free from air bubbles returns to the engine. If the degas bottle is not maintained with enough coolant the engine will suck air in. And you get the air lock that takes out the heat at idle. So on this cooling system you do NOT remove the radiator cap to check or top off the coolant, it is done through the degas bottle.