Long story short, bought an Accord sedan w/ low miles at an excellent price from a local Honda dealership (4-cyl, 5MT). Test drove the car and it had no heat, they had that they would fix it because they couldn't sell a car w/out heat because of their quality assurance policy.

I end up buying the car and the heat goes out; they have taken it back three (3) times and each time the heater will a) blow cold air after awhile or as it is doing now, only blow hotter air under acceleration.

In those fixes, they have replaced the heater core, thermostat, radiator and hoses and flushed the system (no cost to me). This is starting to get old but I'm worried that this heater issue might be a sign of a larger problem in the vehicle that hasn't/wasn't detected; crack?

Suggestions please.

12/12/2012 6:07:28 PM

well, the only thing left is the water pump

12/12/2012 7:45:09 PM

Water pump and timing were done prior to purchase.

12/12/2012 10:35:11 PM

could be air in the system. i'd like to think they'd burp the air out of it after they refilled it, but maybe they've got some real idiots working there.

12/12/2012 10:40:45 PM

That's what I'm thinking but I'm not doing that when they owe me.

12/12/2012 10:45:50 PM

it probably takes longer to drive to the dealership than it does to burp it

12/12/2012 10:49:31 PM

I don't suppose they pressure tested the heads or checked the coolant for hydrocarbons?

12/12/2012 11:26:11 PM

Has anybody thought of a blend door actuator, especially if it's a vacuum servo? The heater control module could be at fault or there may be a vacuum line or check valve not doing its job. Periods of high vacuum could produce no heat, while a drop in vacuum produces heat.

All the stupidly obvious shit has been done, and any real pro shop will have a vacuum fill machine that virtually guarantees no air bubbles.

How many times have you really seen a water pump as the culprit? If you understand the principles behind the typical centrifugal water pump, nothing short of total impeller separation or erosion will cause those kinds of symptoms. It happens, as all of you BMW people know all too well, but I don't think I've ever seen a Honda with this problem. Ever.

12/13/2012 9:55:09 AM

12/13/2012 4:03:16 PM

Quote :

"I don't suppose they pressure tested the heads or checked the coolant for hydrocarbons?"

This makes me skurred.

12/13/2012 6:45:05 PM

Quote :

"Has anybody thought of a blend door actuator, especially if it's a vacuum servo?"

ding, ding, ding.

12/13/2012 10:22:29 PM