I had to replace my heater core. Now when the RPMs climb above 2000, I hear the sound of rushing water from the dash. There don't seem to be any leaks or smell of antifreeze and the heat works. I am guessing trapped air. How do I get it out?

thanks

 

you need to burp the system, park it nose uphill (steeper the better), run the truck with heater on full blast, and radiator cap off. Top off cooling system.

 

Did you ever figure this out? My truck is doing the same thing after I installed a new heater core this weekend. Appreciate any info.. and if burping it fixed it.
Thanks.

 

Try that and take it for a nice drive to add some coolant to top it off.

 

never got it to stop, comes on when you hit the gas hard around 2k rpm. Shop that did work said "the core has a restrictor to slow the water to help extract heat". My BS alarm went off, but it does not leak and does work and no cash to tear dash out just for noise reduction.

 

second that.. I got a similar response only it was .. well thats just the way it sounds.. blamed it on a the fact it was aftermarket.

 

You will know soon enough if you have to do a head gasket. Good luck with it.

 

Ok, I'll bite, what does a heater core have to do with head gaskets?

 

It's making bubbles.

 

Ok, that makes sense. But it's not a air sound like when the core leaked. That sound was there all the time regardless of RPM. This is a jet sound like a using a small fitting on a high pressure hose. And it only lives above 2k RPM

 

Oh, you don't have a gurggle sound you have a HVAC sound. Is your AC hose cold to the touch outside while the other AC hose is hot? A vacuum leak should create a malf in the controls so that is out. Did you mess up the connection of the hoses thru the firewall. It is easy to dislodge one of the seals or the spacer between.

Watch all of his videos, great tips on repairs to a heater on a F150.

http://www.ford-trucks.com/forums/11...ggestions.html

After watching them you can remove the connector assemblies and recheck the seals for damage or dislocation inside the thing maybe even clogged/bent. When you are reved up at highway speeds you are moving a lot of water 5 gallons in no time. It wouldn't take much of a restriction to make a noise.

Also check out his blend door tips for the new repair to them. Slick bushing trick to reinforce the area wher it breaks and make it fit into the actuator.