Fox body heater core

[USAWIT2]

Heater core starting leaking in my 91 last summer so I just bypassed it. Missed it on those cooler days in the fall so figured it was time to replace it.
Doesn't look like OEM ones are available.
Just wondering what brand people are using? Any brands to stay away from or are they all about the same?
Prefer not to have to do it again in a year.

[ZR]

Seen little to no difference brand to brand (beyond OE of course).

[LX89]

I replaced mine in 2006 with one from the Ford dealer.
Made by Valeo.Same company that supplied Ford with clutches.
Sucks if they are no longer available.

It is better built than the previous NAPA heater core which lasted 8 years.

[USAWIT2]

Well hoping the one I ordered lasts for a few years.

Also are these flow restrictors necessary?

I have to check my hoses to see if they had one from the factory.

I ordered new hoses so maybe they will have them?https://uploads.tapatalk-cdn.com/20210126/8d7a71ca981705131f7dd86d88623400.jpg

[ZR]

Not a bad idea.

[fast Ed]

There was usually a restrictor in one side on the factory hoses, and the Ford OEM replacements when available had them too ... so the engineers must have felt they were needed.

[Hutch]

The problem was too much flow at higher rpm through the core. I put a socket in one of mine so it would restrict the flow and I couldn’t wait for the actual restrictor

[USAWIT2]

Well the new Gates hoses I purchased didn't have the restrictor, end up using a 3/4 pex plug and drilled a hole thru it.

Heater core is back in, cars back together, no leaks hopefully it stays that way for a while

[ZR]

^ Nicely done.

[Titanium90]

Well the new Gates hoses I purchased didn't have the restrictor, end up using a 3/4 pex plug and drilled a hole thru it.

Heater core is back in, cars back together, no leaks hopefully it stays that way for a while

Hi there,

I had ordered my heater core along with the hoses through mustang depot here in Canada, and on of the the heater hoses included the restrictor in it. The part # 3943047.

I wanted to ask you, do you have any tips that would be easier to replace the heater core, as I will be doing mine in the spring myslef? Were you able to put the dash back up yourself or you need to have another hand?

[USAWIT2]

Hi there,

I had ordered my heater core along with the hoses through mustang depot here in Canada, and on of the the heater hoses included the restrictor in it. The part # 3943047.

I wanted to ask you, do you have any tips that would be easier to replace the heater core, as I will be doing mine in the spring myslef? Were you able to put the dash back up yourself or you need to have another hand?

Wasn't as bad as I thought is was going to be, LMR and CJ pony parts have some good vids on it.
I was able to do the dash by myself, it's not that heavy but if you have someone that can give you a hand it would be easier

[Titanium90]

Wasn't as bad as I thought is was going to be, LMR and CJ pony parts have some good vids on it.
I was able to do the dash by myself, it's not that heavy but if you have someone that can give you a hand it would be easier

Thanks for the response.
Did you have to remove the gauge cluster?

[Hutch]

Thanks for the response.
Did you have to remove the gauge cluster?

Yes. It is much easier if you remove the seats as well or least the pass side seat. If your car doesn’t have a/c it’s a breeze. If it does, it’s a little more work. Just lots of screws to take out and hopefully put back in

[ZR]

Best done on a day your in a good mood and weather is moderate.

[USAWIT2]

Thanks for the response.
Did you have to remove the gauge cluster?You can if you want but I didn't, just dropped the steering wheel and pulled it forward, just make sure it's not pulling on any wires etc

[m_owing]

Back to the flow restrictor. Replaced all my hoses last summer and ordered a Ford restrictor from American muscle, pictured below but it was too long, not enough room before the hose bends 90 degrees. My old hose had a small brass restrictor the same shape as the yellow one on page 1. I just cut it out and reused. And yes from what I hear it reduces flow because the heater core can’t take the pressure.

[LX89]

I wonder how much longer my 15 year old Ford heater core is going to last.
I sure as hell have no desire to do that shit job again.
Did it twice so far in this car with AC.

Father has a 97 Accord that still has the original yet these Mustangs seem to eat them.

[m_owing]

Did it twice so far in this car with AC.


Did you work on factory AC in a fox mustang?

[hsousa88]

I wonder how much longer my 15 year old Ford heater core is going to last.
I sure as hell have no desire to do that shit job again.
Did it twice so far in this car with AC.

Father has a 97 Accord that still has the original yet these Mustangs seem to eat them.

It’s been almost 8 years since I’ve owned my fox... still 0 desire to do this job.

[LX89]

Did you work on factory AC in a fox mustang?

Yes,factory AC in a 89 5.0 fox Mustang.

[LX89]

The first time I replaced the heater core,I took the car to a garage to remove/collect the R-12.
When the mechanic was finished we were talking for awhile and he said,
"I was glad when you said that you are doing it yourself".

Even a mechanic didn't want to do it,lol.

[ZR]

It's a mind over matter job often times made worse by an aftermarket stereo and or gauges.

[m_owing]

Yes,factory AC in a 89 5.0 fox Mustang.

Did you need any special tools? Like a manifold gauge set? I’m diving into my fox factory AC in the spring. I bought a can of dye, the filling hose gauge and a uv light. I know it works, but there’s a leak somewhere.

[USAWIT2]

You'll need a vacuum pump also, need to make sure there is no air in the system.

[LX89]

You need a disconnect tool to disconnect some of the AC lines.

[m_owing]

You need a disconnect tool to disconnect some of the AC lines.
I have those. I have the small hose/gauge that comes with the AC cans at canadian tire. No vacuum pump.

Did you replace your whole system? Or just swap a bad part? Did you retro fit with r143 or use the r-12A from redtek or duracool etc?

[LX89]

In 2006 R-12 was no longer available and I thought converting to R134a was a waste of money so a mechanic suggested 12a which he installed after I replaced the o-rings on the lines.
In 2017 it needed a recharge so I bought a Duracool 12a kit on sale with gauge and installed one can myself.

My AC system is original except for the o-rings and a few pressure switches.
Even with under drive pulleys I get 39-40*F vent temps.

[m_owing]

Ice cold!
I thought the drier/accumulator needs to be replaced with any exposure to air? They have a desiccant in them that will ruin if exposed for too long. Did you have to test pressure, or pump the air out? What about AC oil? I know the cans have some in them but was it enough?

[ZR]

Soon as the lines are off, plug em off / do not leave open.
However, if accumulator is old, money well spent to replace.
Be sure to vac before refilling.

[LX89]

After I replaced the heater core twice the AC was recharged at a garage where a vacuum was pulled on the system.
I think pulling a vacuum also gets rid of any moisture in the system.(not positive at the moment but I think it does).

I covered the AC lines when they were disconnected while replacing the heater core.
I probably should have replaced the accumulator/drier but the system still works ok,but for how much longer who knows.
Didn't need to add any oil as no major component was replaced.

[m_owing]

Awesome thanks. I heard somewhere that shops won’t touch an R12a ( the duracool/red tek stuff) because it contaminates their r134 system so I kept thinking I’m on my own. But sounds like if I can find a leak, replace the part or o-rings myself then have a shop charge it so I don’t have to buy a vacuum pump or manifold gauge. This is good news! I can’t take the heat anymore!

[LX89]

There must be several garages selling and installing 12a.
I got it at a garage in 2006 and about 7-8 years ago I took my fathers car to a garage for some work and heard a mechanic talking to a customer about using 12a.

[LX89]

Back in the day I replaced the heater core in my parents 71 Comet and grandfathers 77 Cutlass.
It was so easy to replace in those cars.
Heater box was easy to access without having to pull back the dash.

Why can't they design them like that anymore.

[ZR]

My wifes '88 Park Ave had an access door, hardest part was disconnecting hard to reach heater hoses, two screws on the access door and it was out.

[Frankie]

Even on a Fox.....86 and older with no AC the heater core is simple to do -access door right there in the glove box - takes longer to drain the coolant.

Not sure why they decided to complicate things when they added the AC parts to the heater box.