86 5.0 Not Heating Up

[chrismc101]

I just bought my, new to me, '86 5.0. Unfortunantly in NC, it has gotten cold quick this year. So when having it out the 1st time, found that the heat didn't come on after bout 10 minutes.

Does the thermostat just needs replacing or the heater core needs replacing? If it is the core, is it really a bitch to replace? I heard that you have to get behind the dash board to replace the heater core. Is that the only way to replace it and if so, is it difficult to do?

Bottom line, I need my heat but I don't wanna give somebody (like FORD) an arm and a leg in labor charges to replace it.

Can somebody help me out? Thanks stangers...

[HoodStrype]

The 86 is a two piece dash... but still a beyatch. I had an 86 & paid $400 to get someone else to do it for me. You can usually tell if it is the heater core if a "mist" (antifreeze) is coming through the vents. Also, check the two hoses that go into your passenger side firewall... they should be hot. If they are not, you either have an "air burp" in the line or you need a new thermostat if nothing is coming through there... Good Luck!

PS- My 89 has a busted heater core so I feel your pain!

[Ieatcamaros]

If it's the heater core, your windshield will fog up with the defroster on. Or, you will see a wet spot on the passenger side carpet. Does the temperature gauge work? That should help diagnose. You can check your heater hoses like before mentioned. Also, how warm does the upper radiator hose feel?

[chrismc101]

Thanks everybody for your replies so far. Now, I haven't seen a "mist of antifreeze", nor have I had a chance to run the defrost or see a wet spot on the floor. Those two hoses. Should they be hot just while the engine is idle or while I'm running the heater or what? If I do see a wet spot on the passenger side floor, what does that wet spot mean? I guess I'll checked those things tomorrow.

I do have a new thermostat ready to install though. Will a bad thermostat cause it not to heat like it should? Cause it's cold as hell now in North Carolina, LOL...

Thanks for your responses. I appreciate all assistance cause I'm gonna have this '86 pissing on other stangs/imports/whoever, lol...

[~The Jester~]

A thermostat that's stuck open won't let the car heat up. A thermostat that's stuck shut will over heat the engine. If you think it's cold in NC, take a little road trip up here to Ohio! LOL

Change the thermostat, and while you have it apart, flush the heater core. Run a garden hose through it BACKWARDS.

The wet spot on the carpet if it's there is from the heater core leaking. It's supposed to leak out the drain through the firewall, but they almost never do.

Heater core on a NON-AIR car is a piece of cake. Remove heater hoses, remove glove box door, remove 2 screws, slide out the heater core.

Heater core on an AC car is a baaaaad thing. Start with the left rear taillight and work your way in from there. Little exaggeration, but it's a royal pain. Let me put it another way, with the 8 point cage in my stang, the heater core almost CAN'T be changed. Just not enough room in there anymore.

Good luck, let us know!

[chrismc101]

Well, the thrmostat thing sounds good cause I have a brand new one.gasket ready to replace. Now my question is, "Where is it located?" It's in the engine bay close to firewall, right? I hope I don't have to rip the dash down to change the thermostat too! LOL...

[HoodStrype]

Umm... follow the upper hose from the radiator. It's a pain to get the housing off sometimes cause it takes small hands to get there. It's right where the upper radiator hose meets the motor- check this out... autozone has a chilton's manual online...

http://www.autozone.com/servlet/UiBr...3d801947f9.jsp

Like Jester said, if you're looking for the heater core you have to rip the dash out to take it out... bummer. As old as these cars are now the dash will probably crack and that's why I won't touch mine. It's on the passenger side behind the firewall. If you see those two hoses going into the fire wall, they're connected to it. If they (2 copper pipes) are just jutting out and the hoses are connected to each other, then someone previous has bypassed the heater core. Check right behind the passenger valve cover I think. Good luck!

[chrismc101]

Thanks, that's some good chicken, lol... I like the Mustang family already. It feels good being a part of an ever growing fam!

[mpj76]

It is such a major pain in the ass to remove and replace the dash. You are also risking developing new creeks and rattles. Sometimes the wet spot on the floor will actually be under the floor mat AND carpet. One option is to buy an auxilliary heater to get you through the winter.

[Ieatcamaros]

Maybe this pic will help. On the thermostat housing, you can see one bolt. The other one is 180* away. The one you don't see is the one that is a little challenging.

[chrismc101]

Thanks for all the info family... Plus it gives me knowledge of my car and it's workings.