Got radiator Replaced. Now heat does not work on idle & water sloshing sound

[2.7t]

Had the ratiator replaced and afterwards, I'm hearing the sound of water rushing upon cold ignition and every time I accelerate. The sound is not heard during turns or braking which leads me to think it is something coolant bubble related.

The thermostat is also new.

So im hearing that the car shoukd be driven on the free way with heat and ac alternating to get the bubble out automatically. Some are saying there has to be the bleeder valve which must be opened to release the air.
Ive put maybe 50 miles on the car since the repair and only drove 15 miles on freeway (on the way from repair to home) The rest (4 days) have been local driving (4 miles one way and 4 miles back at night after 10 hours so engine is cold again) (so engine / engine oil doesn't get to full temp although coolant temp does)

The heat starts on idle when I press the gas and rev to 1500 and when it hits, I can hear the sloshing sound. What should i do? Drive on freeway and see if it clears up or take it back?

[Ilya]

If you have air in your system, you need to burp your car, basically. If you Google it, you'll see a ton of videos on how to get air out of a system.

But to me, if it's sloshing around, that makes it sound like there isn't enough in there to begin with...which may be why you have more air than coolant?

I'd probably go back there and complain.

[2.7t]

If you have air in your system, you need to burp your car, basically. If you Google it, you'll see a ton of videos on how to get air out of a system.

But to me, if it's sloshing around, that makes it sound like there isn't enough in there to begin with...which may be why you have more air than coolant?

I'd probably go back there and complain.

I am going back today. But the coolant reservoir is above max. How would it be low?

[2.7t]

It also does not overheat. So i'm stumped.

[Ilya]

The reservoir is above max? Kinda odd IMO.

And also, the reservoir I believe is only there to take any excess from the actual system I believe. But it can be filled individually from what I remember. You still might not have enough in the actual system. When the car is cold and you open the radiator cap, do you see fluid towards the top of the neck?

[2.7t]

The reservoir is above max? Kinda odd IMO.

And also, the reservoir I believe is only there to take any excess from the actual system I believe. But it can be filled individually from what I remember. You still might not have enough in the actual system. When the car is cold and you open the radiator cap, do you see fluid towards the top of the neck?

I took the car back. They are bleeding the system once again. But told me my NEW geniune Nissan radiator cap 2 weeks old was letting air into the system. Does that sound geniune? The cap is literally brand new 2 weeks old and geniune Nissan. Either way, I'm getting the part replaced since it's not costly.

[EdBwoy]

I have some thoughts.
1. How can my coolant be low yet my reservoir is above max?
If you have an air pocket trapped in a middle spot. Think of it like a coolant-air-coolant sandwich. When the engine heats up, the upper coolant layer (nearest the reservoir) will be purged into the reservoir. This means the cap is doing its job and the seal that prevents coolant from escaping the cap is doing its job; in effect redirecting coolant to the reservoir - but air is not really being purged.
*If the air pocket is at the top, that's how the system "purges itself out".

2. My new cap is letting in air. What gives?
New is not necessarily perfect, but I thought rad caps, being pressure equipment, would each be tested before release.
But yes, if the upper seal (the one that is squeezed against the filler neck) is bad, then air can be sucked back in to the system. This seal is supposed to keep air from entering the system, thus creating a vacuum when the engine cools down and the coolant contracts. This vacuum is what sucks the coolant back from the reservoir.
*Again, an air pocket even when sucked in, will typically stay at the top, and if the cap is ok, air is the first to be purged out upond expansion... and when it cools down, since the reservoir is fed from the bottom, coolant is sucked back in.

Edit to circle back on the thought: When this sandwich cools down with insufficient vacuum, then the coolant is not sucked back from the reservoir and the level inside the filler neck is low.

[BlackCat81]

These cars can be really tricky to get all the air out. If your coolant level is above the max line, don't sweat it. When the pocket of air escapes it'll draw the coolant level down.

[jiggersplat]

^^^ what he said. they are notoriously difficult to get all the air out and the most common symptom is lack of heat at idle (or at all). you may need to have it vacuum bled.

[2.7t]

^^^ what he said. they are notoriously difficult to get all the air out and the most common symptom is lack of heat at idle (or at all). you may need to have it vacuum bled.

If I go to the dealer for the coolant flush, will they do all that?

I had the cap replaced, drove 70 miles and still hear sloshing and no heat at idle.

Mechanic suggest to drive car around and the bubble will purge our in few days.

I don't understand how the car doesn't overheat in this manner?

[2.7t]

These cars can be really tricky to get all the air out. If your coolant level is above the max line, don't sweat it. When the pocket of air escapes it'll draw the coolant level down.

The thing is, will the air pocket escape automatically just by driving around?

[2.7t]

These cars can be really tricky to get all the air out. If your coolant level is above the max line, don't sweat it. When the pocket of air escapes it'll draw the coolant level down.

The thing is, will the air pocket escape automatically just by driving around?

I just read that basically I need to open radiator cap and turn heat on to high and idle/Rev engine for 30 mins to hours until the bubble comes out. Is that it?

[yomoms16]

There is a bleeder screw. Located on the heater core hose. On the passenger side firewall. Cant miss it when u look there.

1. Open ur radiator cap. Fill it up the radiator all the way. Then close it again.

2. Unscrew the bleeder valve a little. To give the air a chance to escape...

3. start ur car and put the heater on to the highest. Which should be 90 degrees.

4 as the car warms up. U should hear the hissing sound coming from the bleeder screw. Which would mean the air is escaping. Keep an eye on it. Because if u see coolant or steam coming out. Thats when u want to close the bleeder valve.

5. Let the car cool down. U could either put on the ac. So the fans kick in to cool it down. Or just wait. If ur not in a rush. The repeat. Steps 1-4. Again

6. Once u start to get heat at idle. All of the air is almost out. And once car is cooled down. Now u can completely remove the bleeder screw. And whilst filling up the radiator. U should see the coolant coming out of the bleeder valve. Which means the air is out. Ps. Please be very carful whilst performing. Theae steps. Because when coolant is hot. It can scald u. And have alot of thick towel around. Just in case whilst doing this. And if anything i said was unclear. U can refer to the owners fsm manual. Thats how i leanred to bleed my car after several failed attempts. Just like u. Good luck

[BlackCat81]

^^^ what he said. they are notoriously difficult to get all the air out and the most common symptom is lack of heat at idle (or at all). you may need to have it vacuum bled.

If I go to the dealer for the coolant flush, will they do all that?

I had the cap replaced, drove 70 miles and still hear sloshing and no heat at idle.

Mechanic suggest to drive car around and the bubble will purge our in few days.

I don't understand how the car doesn't overheat in this manner?

I do vacuum flushes at the dealer to help with air pockets. The air is trapped in the heater core, hence the sloshing noise. The car won't overheat because the coolant is still circulating. You can try cycling between revving the engine and letting it idle, that'll help purge the air. Do it with the engine warm.

[bicsintegra]

There is a bleeder screw. Located on the heater core hose. On the passenger side firewall. Cant miss it when u look there.

1. Open ur radiator cap. Fill it up the radiator all the way. Then close it again.

2. Unscrew the bleeder valve a little. To give the air a chance to escape...

3. start ur car and put the heater on to the highest. Which should be 90 degrees.

4 as the car warms up. U should hear the hissing sound coming from the bleeder screw. Which would mean the air is escaping. Keep an eye on it. Because if u see coolant or steam coming out. Thats when u want to close the bleeder valve.

5. Let the car cool down. U could either put on the ac. So the fans kick in to cool it down. Or just wait. If ur not in a rush. The repeat. Steps 1-4. Again

6. Once u start to get heat at idle. All of the air is almost out. And once car is cooled down. Now u can completely remove the bleeder screw. And whilst filling up the radiator. U should see the coolant coming out of the bleeder valve. Which means the air is out. Ps. Please be very carful whilst performing. Theae steps. Because when coolant is hot. It can scald u. And have alot of thick towel around. Just in case whilst doing this. And if anything i said was unclear. U can refer to the owners fsm manual. Thats how i leanred to bleed my car after several failed attempts. Just like u. Good luck

exactly I had this problem when I changed my radiator and flushed my ATF fluid, you can do all of the suggestions people have mentioned without this step you will still have air trapped in the system. bleed it out with the little valve which is near the firewall on my '06, after I did this no problems whatsoever.

[szh]

I just read that basically I need to open radiator cap and turn heat on to high and idle/Rev engine for 30 mins to hours until the bubble comes out. Is that it?

Whoa. I'd never run the engine - let alone that long - without the radiator cap on! Use the bleeder screw mentioned ...

Z

[2.7t]

I just read that basically I need to open radiator cap and turn heat on to high and idle/Rev engine for 30 mins to hours until the bubble comes out. Is that it?

Whoa. I'd never run the engine - let alone that long - without the radiator cap on! Use the bleeder screw mentioned ...

Z

Okay.
So leave the bleeder valve open and radiator cap closed?

also had another question:
when the radiator gets relplaced, is the transmission oil cooler built into the radiator? i ask because i just thought i may have lost some fluid while the shop did it. Not behaving funny, just trying to take it to the brim of ATF.

[2.7t]

There is a bleeder screw. Located on the heater core hose. On the passenger side firewall. Cant miss it when u look there.

1. Open ur radiator cap. Fill it up the radiator all the way. Then close it again.

2. Unscrew the bleeder valve a little. To give the air a chance to escape...

3. start ur car and put the heater on to the highest. Which should be 90 degrees.

4 as the car warms up. U should hear the hissing sound coming from the bleeder screw. Which would mean the air is escaping. Keep an eye on it. Because if u see coolant or steam coming out. Thats when u want to close the bleeder valve.

5. Let the car cool down. U could either put on the ac. So the fans kick in to cool it down. Or just wait. If ur not in a rush. The repeat. Steps 1-4. Again

6. Once u start to get heat at idle. All of the air is almost out. And once car is cooled down. Now u can completely remove the bleeder screw. And whilst filling up the radiator. U should see the coolant coming out of the bleeder valve. Which means the air is out. Ps. Please be very carful whilst performing. Theae steps. Because when coolant is hot. It can scald u. And have alot of thick towel around. Just in case whilst doing this. And if anything i said was unclear. U can refer to the owners fsm manual. Thats how i leanred to bleed my car after several failed attempts. Just like u. Good luck

OK thanks for the instructions. the radiator is already full and coolant is on the top of the neck.