Heater works OK.

[cazsper]

This is actually about my '68 coupe but I will need to know for my '73 as well. U just replaced the theater in my '68 mustang. Now, it takes forever for the heater to get hot. But when it does, the heat only comes out of the bottom. I hardly feel anything coming from the defroster. Is this common? Has anyone ever installed a modern heater setup in their car? My '73 doesn't have a heater box and I will have to get one. But without a defroster, I can't drive it when it's cold.

 

[Wolverine]

This is actually about my '68 coupe but I will need to know for my '73 as well. U just replaced the theater in my '68 mustang. Now, it takes forever for the heater to get hot. But when it does, the heat only comes out of the bottom. I hardly feel anything coming from the defroster. Is this common? Has anyone ever installed a modern heater setup in their car? My '73 doesn't have a heater box and I will have to get one. But without a defroster, I can't drive it when it's cold.

It gets cold in Sunnyvale?

What does just replaced the heater mean?

The fan motor?

The controls?

The heater core in the heater box?

What is a modern heater setup?

As far as I know, the heater setup in 68 -78 mustangs is about the same. If it is taking a long time to heat up, your thermostat may be stuck open...or missing.

To check this, grab your wifes or mom's meat thermometer. When your car is dead cold, remove radiator cap, fill radiator and start car. The fluid in the radiator should be calm. If it is moving pretty good, then your thermostat needs replacing. If not, put in the thermometer. When the water starts to move RAPIDLY check the temp. It shouldn't move until the temp is 180. Anything less and you will still want to replace the thermostat as it is opening to soon.

Another issue is in regards to the heater hoses, the 2 hoses that come out of the firewall to your water pump. If your engine is hot, but the hoses are not, your heater core is plugged. You will need a 12 pack of beer and a new heater core for this task.

Anyways, answer the questions at the top, and do the thermometer test and get back.

 

[cazsper]

Sorry for being vague. I have a new heater core that was replaced about a year ago. I had the blower motor replaced about 4 months ago. I am still using the original heater controls. As for the temp, the car seems to warm up after just a few minutes. I will check the thermostat the way you mentioned.

I was wondering if I could use a modern heater from a 5.0L mustang.

 

[Wolverine]

Sorry for being vague. I have a new heater core that was replaced about a year ago. I had the blower motor replaced about 4 months ago. I am still using the original heater controls. As for the temp, the car seems to warm up after just a few minutes. I will check the thermostat the way you mentioned.

I was wondering if I could use a modern heater from a 5.0L mustang.

As far as I know, a "modern" heater works the same way as our heater. Hot water runs into the core and the air blows around it. There is a modern AC feature that allows only interior air to recirculate past the heater/ac cores. Perhaps that is what you are talking about.

But, come on. You live in Sunnyvale. Does the temp ever get below 28 degrees? Your heater should allow you to drive a convertible 7/24/365. If not, you have a problem.

If your air is not hot(and check the water temperature via meat thermometer remembering not to allow meat thermometer to fall completely into radiator), then perhaps your air diverter is stuck open, not allowing air to pass by the heater core. Additionally, the seal may be bad also preventing air to the heater core. If you replaced the core yourself, perhaps you checked this.

With the TEMPERATURE control slide in cold, only a small amount of outside air is diverted past the core. When the slide is on WARM, all the air will go past the core.

Make sure you can "feel" the diverter gate moving as you slide the temp control. If not, then you need to check the back of the heater control above the hump. Maybe the wire hook just fell off the control lever.

 

[midlife]

Doesn't a 68 use vacuum to control the doors? If so, I would suspect a failed vacuum hose.

 

[Wolverine]

Doesn't a 68 use vacuum to control the doors? If so, I would suspect a failed vacuum hose.

I believe vacuum doors are only used with factory AC.

 

[cazsper]

Below 28 degrees? That's rediculous. If it got that cold, they would close the schools..lol

Ill look into the heater.

 

[peche 71]

related to what Wolverine said, i had a 70 that had the same problem, and I had to reach under the dash to move the lever to open up the defroster vent, perhaps that cable needs some lube?

 

[cazsper]

Very possible. I'll check it this afternoon. Thanks...

 

[t.klapperich]

Check to see that your defrost duct work did not come apart. The controls move a flapper that diverts the direction of the air. That is part of the heater box. Many times they get stuck and won't move. Also I have a heater box for a 73. It has a bad core in it but since you have a new one it will work for you. P.M. me if you are interested.