On cold days the heater air goes cold about 10 seconds after I turn on the fan. Instead of getting a new heater core I put in a new thermostat and added new coolant after flushing. But it didn't solve the problem. Anyone?

pull the hoses and flush out the heater core with either your garden hose or an air compressor or both. might need to get some cleaning agent in there and actually clean it out....but you wouldn't want anything harsh for your heater core. i'd see how just a basic flush does, i'd bet alot of gunk comes out.

 

someone on xt6.net just had this same problem and fixed it by blowing the heater core as i just mentioned. someone else actually bought a small pump and created a little system to keep a solution of water and cleaning agent running through the heater core. pretty hard core just to flush it out, but if it's bad enough maybe that's necessary? you can go to www.xt6.net and read the current thread about it.

I would flush it with the garden hose, but reverse flush it, so the hose is on the outlet side of the core. Also check to make sure the air door is closing off the cold air when the heat is on. The cable sometimes breaks off the end of the lever.

Thanks for the replies!

 

Will a flush work if there is hard build up in core?

 

I was thinking of getting a new core and doing the simple replacement by cutting a hole in the side of heater box as written by someone on the forum. But I wanted to try everything else before it came to that.

 

I never thought of checking the cable that keeps the cold air out. That just might be it. If not then I'll reverse flush and if that does not work then replace the core.

A simple garden hose flush won't remove hard deposits, but it might be enough. Like you said, it's worth a try before you spend the time and money on replacing it. It worked for mine.