Rep Power: 0

Hi all

I have been have this issue for a few months now.

The heater on my 05 is either not working or puts out very little heat only when the car has been driven for more than 30 minutes (even in 70degree weather). There are no issues with overheating or any other mechanical problems I currently know about.

We replaced the coolant (with honda 50/50), tried to backwash the system to ensure there was no debris clogs (only used a garden hose that did not have the greatest pressure), checked that the valve was opening and closing (turning the dial from cold to hot), and replaced the thermostat.

I finally gave up this weekend and took the car to a Honda dealership, that ran a 99$ diagnostic only to come back and say they did not find anything truly wrong. The dealership stated that the temp on both sides of the core was at 180degrees. They claim that they also adjusted the valve.

I am tempted to take it some place else and get to them flush the system again and try to put a little water pressure into the core and see if any debris comes out. Would it also be a good idea to have the valve replaced?

Everyone I have spoken with about the core has stated that there should be no way that the core is bad. Replacing it is pretty much out of the question as i have been quoted 1500$ for parts and labor and being a graduate student, this is not possible.

Any help?

 
Rep Power: 209

first i will ask the obvious.....is your engine up to normal temperature, and still no heat?

meaning, is the temp guage/needle at the "normal" position slightly lower than half way?

assuming your answer to that question is yes.....you most likely have a clogged heater core, the coolant is not passing through it fast enough and the blower fan is cooling it down,

try this....leave your heat and blower fan OFF and let the engine get up to full/normal operating temperature, now turn your heat on, and the fan to the highest setting, do you have heat for a min or two? then it cools off?

yes = clogged heater core

it is also possible that the system still has air trapped in it and it needs to "burp" it out

on a side note, you should never flush or put anything else in these cooling systems besides OEM honda coolant, your garden hose likely did more harm than good

 
Rep Power: 0

Yes, this is when the car is fully warmed up and the needle is about half on the temp gauge

I believe what you are describing is exactly what is happening. I will check tonight.

As far as the garden hose, we drained the system and tried to flush out any debris as instructed by a friend who is a honda mechanic.

The system has also been "burped" multiple times as you described. this was actually the very first thing we did

 
Rep Power: 518

That didn't hurt anything IMO.

Did it have good, rapid flow? Or was there serious restriction?

Did you check that the water valve can actually go fully closed and wide open when you had the hoses all apart? (I've seen the valve break at the shaft and not move when the lever does.)

Can you verify this yourself?

Max heat, fan on full blast, engine fully warmed up, feel the 2 heater hoses where they enter the firewall. Are they both too hot to hang on to, or is only one hose that hot?

 
Rep Power: 518

Did burping help? Does air come out each time?

The one common way these would repeatedly need to be burped, is a blown head gasket.