Water sound from heater core

[98EXPnSRQ]

I did a radiator flush over the summer and ever since I hear a water whooshing sound when I accelerate. I assume there is air trapped in there. What can I do?

 

[69Hcode]

Run the heater to open the valve to it. Then drive it.

 

[98EXPnSRQ]

It finally got cold enough here to run my heater. I have run it for a few days and i still get the water gushing sound. Not sure where to go from here. Is there a procedure to bleed the air?

 

[jlo82585]

In newer vehicles this is actually becoming a big issue but in the older fords the only real option is just to run the heater all the time, eventually it will work its way out. you could try pressurizing the system with a cooling system test kit but depending on where the bubble is it could be very stubborn to get out. I had an Isuzu I was working on that had a bubble I couldn't get out. It got rented to California ( im in Iowa ) and it was halfway back when the low coolant light came on ( the bubble was large enough it brought the coolant level down when the system finally burped it out ). So it could take 50 miles or 5,000 miles but it eventually will come out. You could help it out by loosening up the heater core outlet hose clamp while the engine and heater is running but that is not easy to get to and you may very well burn yourself so I would just let it work its way out naturally. They also make new fittings to fill your cooling system from the drain valve to eliminate the bubble all together but im thinking those are expensive.

 

[98EXPnSRQ]

I will see if I can loosen the outlet hose like you said and see what happens.

 

[stamp11127]

Park on a decent incline so the the coolant reservoir is the highest point in the system. Run the engine up to temp squeezing the upper rad hose once the t-stat opens. Squeeze the hose multiple times. Once the level in the bottle drops the air is out.

 

[98EXPnSRQ]

Park on a decent incline so the the coolant reservoir is the highest point in the system. Run the engine up to temp squeezing the upper rad hose once the t-stat opens. Squeeze the hose multiple times. Once the level in the bottle drops the air is out.

Well, that sounds easy enough. I will give it a try.

 

[IMINYOURCHAIR]

in my experience with this trucks setup, just add some extra coolant to the bottle, maybe 1 1/2 inch above the full cold mark. start the truck, let the tstat open up and squeeze the upper hose a few times. you will end up having to let it belch some out of the bottle when it expands but it usually gets all the air out of mine. I believe it's because the extra fluid pushes that much harder on the bubble forcing it over it's obstacle and into the radiator, it then goes out of the 1/4 hose to the reservoir

 

[98EXPnSRQ]

Just thought I'd update this post. Adding the extra coolant did the trick. I added it when it was cold well above cold fill line, but not completely full. I drove with the heater on a few days and noticed it was quiet. I checked the level when it was cold and it was actually down to the cold fill line. There must have been quite a bit of air in the system. Thanks for the help.

 

[1955moose]

I agree with in my chair leave cap off of expansion tank put heater on and just run it. Squeezing hose doesn't hurt. Your truck is like a baby, it needs to be burped.

 

[98EXPnSRQ]

Well, it's still doing the water gurgling. So either I have a pin hole on the return side that's sucking in air, or an air bubble that won't come out. I don't have any sort of leakage. I'm going to pull the rear heater lines off near the passenger side wheel well and flush both heater cores. Then I'm going to cut the line somewhere near the T's and install a flush T with a removable cap. At least I'll be able to bleed the air out of the front heater core that way.

 

[1955moose]

If you suspect you have a pin hole or leak, you will need to pressurize system with a radiator pressure tester. Pump it up to whatever is on cap. The only problem is if you have a questionable water pump or radiator it will open the tiny hole and make it larger. But if you have a leak now is the time to fix. Also the pressure of the pump might get rid of the trapped air. Good luck.

 

[98EXPnSRQ]

Easiest fix ever... I replaced the radiator cap with a new one. I noticed after the engine had cooled overnight and I opened the cap, there was always a whoosh of air being sucked back into the bottle. The valve in the cap wasn't letting the system breathe properly and air was being sucked in from somewhere and trapped in the system. I suspect one of the crappy o-ring hose connections in the heater core hoses.