Honda Repair: Heat not working on Honda Odyssey, coolant level, honda odyssey

Question
QUESTION: Happy New Year!  I have a problem with 2001 Honda Odyssey Ex with front and rear A/C-Heat.  I had the coolant flushed a week before a holiday trip from north Florida to Indiana.  Heat worked fine before flush but noticed on the trip that the heat was not running at full capacity.  Air is not getting hot.  It instead will blow “luke warm” air and the vent in the dashboard on the passenger side blows cool air.  The A/C works fine, as always.  The engine did not overheat on the trip so I’m guessing the thermostat is working.  I’ve been told the system may not have been properly purged when flushed and refilled.  Is there something I can do now to purge the system myself?  And, if that doesn’t work, what else might be causing the problem (stuck valve or a vacuum problem)?  I have to believe it’s related to the coolant flush since the heat was fine before the flush.  Any help or suggestions with detail would be greatly appreciated.  I’ve found shops in my area seem to have a hard time fixing stuff the first time unless I can tell them what is wrong so I’m not anxious to go back to shop without having a pretty good idea of what is wrong with it.  Thanks for the help.

Ron


ANSWER: It sounds like there is an air pocket in the heater core. This happens when the coolant isn't purged correctly after a service. The easiest thing to do is check the coolant level when the engine is off & cold. Take the radiator cap off & top your cooling system off with 50-50 mix of antifreeze. Then run your engine at 2000 rpms until the cooling fans cycle. You should have the front & rear heat on high & on defrost. This should purge air out of the cooling system, or better yet, take it back to the repair shop that did the work & make them redo their work. They should have checked that your cooling system was operating normally before they released the car back to you. Hope this helps.

---------- FOLLOW-UP ----------

QUESTION: Thanks for the very fast reply and helpful suggestion.  One point of clarification - after topping off the antifreeze do I leave the radiator cap off to run the engine at 2000 rpms or do I put the cap back on then run the engine?

Thanks again.

Ron

Answer
Sorry, you need to put the cap back on. Leaving the cap off while the engine is running at 2000 rpms would make a nice mess. After the fans cycle, let the engine cool off again & recheck the coolant level. Also, make sure the overflow bottle is topped off.