Engine Perplexing issue with heat ...

MrPerfect2 · Sep 12, 2019

Don’t BBQ ME ! You guys have all heard about my hot temps - 225-240 degrees - so , I am going to replace radiator - I noticed when car is at 225 degrees the heat does not blow hot - guy I bought from changed thermostat and it does look like he did by the caulking - and top hose reads 230 and bottom reads 195 - so I suspect flow - what do you suggest - change rad first ?

Wayne Waldrep · Sep 12, 2019

Got a good laugh at that first sentence!! Oh, and I promise no BBQing. As much car trouble as I've had this week, I'm not even holding any matches.

JD1964 · Sep 12, 2019

1) Low coolant will make the heat not blow hot. 2) The heater core could be clogged internally, just like radiators do. 3) The vacuum lines that are controlled by the buttons on the dash could be disconnected. 4) The vacuum diaphragm that opens and closes door in the heater box could be stuck or ruptured.

Thats a few things to check anyway

MrPerfect2 · Sep 13, 2019

Coolant is topped off and burped - the vacuum lines on temp knob work - ( got ac and heat blows hot for a few minutes then just warm ) - the core could be clogged and I like the flap idea check - btw , how difficult is it to change heater core on 91 - thanks

Olivethefet · Sep 13, 2019

MrPerfect2 said:
how difficult is it to change heater core on 91

Not the end of the world but it SUCKS. You have to drop the dash and either cut a hole in the heater/AC box or pull the entire box out use a heat gun and other tools to open the box and replace the core. I think changing a Fox heater core is one of those "right of passage" things! I did mine less than a year ago. You can find it in my progress thread. There are some good Ytube vids on it also.

MrPerfect2 · Sep 13, 2019

Ok - it’s not leaking so I won’t change out - how does the flap work and is that easier to get to?

Olivethefet · Sep 13, 2019

You should be able to look up at the heater box from the passenger side and see a silver vacuum module on the side of the box. I dont think its to hard to get to with everything in place.

Olivethefet · Sep 13, 2019

This is a pic of mine. You should be able to get it off with out much trouble.

Now if the defrost quits.... well then you have to get to this one.

As you can see from the location it would be very difficult to get to without dropping the dash. Thinking back on it now I should have replaced both when I had the box out of the car.

MrPerfect2 · Sep 13, 2019

Wow - that looks complex ! Who needs hot heat .... warm heat and a coat should be fine

Olivethefet · Sep 13, 2019

Heater cores on these cars are notorious for going out. Especially if it still has the factory unit in it. This is a pic of my old core. It was not leaking, but I was changing the AC evaporator and went ahead and ordered a new one. I'm glad I did.

Wayne Waldrep · Sep 13, 2019

For goodness sake, if you get a heater core get the Motorcraft one. I pulled the dash and put an LMR one in and it leaked a month later. Got another one...pulled the dash a second time and installed it (dummy) and it leaked the second it had fluid in it. So this time I did what I should have done to start with and got a Motorcraft one. I so wish I would have taken a pic of the two side by side. Think Shaq standing beside Spud Webb. No kidding, it doesn't even look like the same part. It hasn't leaked since. And just pull the whole thing out and do it right. Don't cut the box. Many people have done it i know and no offense Nick.
Since I was doing it a third time I took the opportunity to also replace the A/C evap. I also removed everything down to the firewall and cleaned and painted the metal dash frame. I also cleaned all the factory goop off the wiring that had been slowly falling in my floor for years. I rewrapped all the wiring and zip tied them in place. Hopefully, it's done for years to come.

Olivethefet · Sep 13, 2019

No offense taken! Cutting out the top of the box was the only way that I knew to replace the heater core with out removing the entire box from the car. Someone had already taken the box out of my car at some point and pulled the two halves apart. It's now secured with screws. Made it a lot easier to change the core and evaporator.

I didn't know that about the LMR heater cores. I bought a kit to replace the entire AC system from www.Foxresto.com. I also brought the heater core from them. It's all aluminum. Definitely not as beefy as the one that I took out. Hopefully it doesn't start leaking anytime soon! If it does at least I know how to fix it.

Wayne Waldrep · Sep 13, 2019

As a good gesture to start the weekend, I won't tell you that that is the same heater core LMR sells....

Olivethefet · Sep 13, 2019

Real time recon · Sep 13, 2019

MrPerfect2 said:
Don’t BBQ ME ! You guys have all heard about my hot temps - 225-240 degrees - so , I am going to replace radiator - I noticed when car is at 225 degrees the heat does not blow hot - guy I bought from changed thermostat and it does look like he did by the caulking - and top hose reads 230 and bottom reads 195 - so I suspect flow - what do you suggest - change rad first ?

"No BBQ-ING" lol ....some of the guys (HERE) live on BBQ other members .

Blown88GT · Sep 13, 2019

MrPerfect2 said:
Don’t BBQ ME ! You guys have all heard about my hot temps - 225-240 degrees - so , I am going to replace radiator - I noticed when car is at 225 degrees the heat does not blow hot - guy I bought from changed thermostat and it does look like he did by the caulking - and top hose reads 230 and bottom reads 195 - so I suspect flow - what do you suggest - change rad first ?

Probably needs more air flow through radiator.
Add Cobra grille insert or make your own. Or cut holes like I did.

MrPerfect2 · Sep 13, 2019

I took front tag off and it helped a bit you are right - the front has poor ram air design

General karthief · Sep 13, 2019

Who is Spud Web?

Wayne Waldrep · Sep 13, 2019

General karthief said:
Who is Spud Web?

Tiny former basketball player.

Blown88GT · Sep 15, 2019

MrPerfect2 said:
I took front tag off and it helped a bit you are right - the front has poor ram air design

It has nothing at idle. Need a good fan with high cfm's.

Engine Perplexing issue with heat ...

MrPerfect2

Wayne Waldrep

Before I post a pic, do you have one of yours?

JD1964

there is enough sticking out to grab on to

MrPerfect2

Olivethefet

I will own your nuts! LOL

MrPerfect2

Olivethefet

I will own your nuts! LOL

Olivethefet

I will own your nuts! LOL

MrPerfect2

Olivethefet

I will own your nuts! LOL

Wayne Waldrep

Before I post a pic, do you have one of yours?

Olivethefet

I will own your nuts! LOL

Wayne Waldrep

Before I post a pic, do you have one of yours?

Olivethefet

I will own your nuts! LOL

Real time recon

Mustang Master

Blown88GT

MrPerfect2

General karthief

wonder how much it would cost to ship you a pair

Wayne Waldrep

Before I post a pic, do you have one of yours?

Blown88GT

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Engine Perplexing issue with heat ...

Before I post a pic, do you have one of yours?

there is enough sticking out to grab on to

I will own your nuts! LOL

I will own your nuts! LOL

I will own your nuts! LOL

I will own your nuts! LOL

Before I post a pic, do you have one of yours?

I will own your nuts! LOL

Before I post a pic, do you have one of yours?

I will own your nuts! LOL

Mustang Master

wonder how much it would cost to ship you a pair

Before I post a pic, do you have one of yours?

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