View Full Version : {HVAC}Hidden Treasure! How to change a heater core easily!

Grand Marquis GT
09-21-2004, 03:57 PM
"Well as far as easy, we removed the Dash Pad and the glove box, then removed the 2 screws on the bottom inside the passenger side and then the one bolt on inside of the engine compartment. We did not disconnect all the wires/hoses as the manual says to do. Once we had the box pulled away fromt the firewall, we removed the 4 bolts on top the heater core (hold down plate) and then used some crative manuevering to get the core out!

I pulled the ATC sensor and cleaned it really good with Simple green and Alchohol. Put it back togheter and now it works.

If you want to bypass the ATC just remove the vacum hose (clear) that goes to the diaphram that sits on top the heater core under the dash. "

I found this, and thought id share :rock:

09-21-2004, 04:15 PM
Got any pics? I need to get mine done soon and I am not looking forward to it at all.

8 posts... ah hah hah

Grand Marquis GT
09-21-2004, 04:17 PM
No, but ive never actually done the job either.

This is what someone else wrote.

09-21-2004, 09:11 PM
oooooo excellent

09-22-2004, 12:09 PM
I always just pull off the hoses, then clamp them off/raise them up high enough nothing will come out... take out the heater core's fasteners... and pull on the dash until I can pull the heater core (well... actually pulling on the plenum) out enough that hte pipes are out of the holes... then turn it up side down...pull it out.

Reverse process for putting one back in. Oh, I think I also took an air compressor and blew out all I could from the old one, right after disconnecting the hoses.

Grand Marquis GT
09-22-2004, 12:10 PM
thats a great method too, nic!

09-22-2004, 03:56 PM
Yeah, the only thing is... every time I do it, I'm afraid I'm going to put a horrible crack somewhere in my dash. Hasn't happened yet, though. And also, my dad repaired the plenum once... one of the door valves (I think it's one of hte doors inside it that controls which way the air flows). It's "hinge" (which was basically a peice of flexible material) broke. So he made a new one, consisting of a 3/16" metal rod, which pokes through the ends of the plenum, and I forget how it attaches to the door. But that rod sticks out the bottom about 3/8", so it gets caught on the carpet when taking it out and wrestling it around.

10-09-2004, 06:12 PM
good tips...

the only one ive done was on my 72 f-100. it has factory under the dash air, so there were over 70 screws to take off. took me 12 hours.

is this a common thing that has to be done to boxes?

10-10-2004, 02:01 AM
HOllllllly crap...... 70 screws!!!!! That's terrible.

ANyway, I think the heater core has been changed maybe 2 or 3 times on my car, since we've (family) has owned it, which is just a little over 19 years.

10-15-2004, 12:25 PM
how will i know if it goes bad?

will it do like my truck and start leaking coolant all over the passenger side floor?

10-15-2004, 12:37 PM
how will i know if it goes bad?

will it do like my truck and start leaking coolant all over the passenger side floor?

Well... I suppose if it's a HORRIBLE leak, it might do that. The way I usually know is... my nose tells me. IF you turn your heater on, you'll smell hot coolant (if the engine has been running long enough to have hot coolant in the heater core). Also, if you have your defroster on, there might be an abnormally cloudy appearance on the inside of your windsheild.

Also, the way I caught mine this last time, Was in the summer. I had the A/C on. I didn't smell much, but I noticed that there was visible clouds (very very light, but still noticable) of white comming out of my vents. The heat/cool mix valve doesn't seal perfectly, so a little air still passes thorugh the heater core and mixes with the cool air. The cloud was probalby steamed coolant that had condesed in the cool air, and therefore looked like clouds shooting out of my vent.

Also, if you check your coolant overflow level (and /or radiator), and it's going down, but you cant find a leak anywhere in the engine compartment ( :lol: ), heatercore could be leaking.

12-25-2004, 02:06 PM
I did a heater core on a 85' Riveria and that sucked so much ass. The core was only like 10 bucks but all the work needed putting one in was hell. After about 5 hours of smelling coolant I wanted to never smell it again.

03-06-2005, 06:55 PM
Yeah i might have to do this soon im gettin a lil fog on my front windshield

03-06-2005, 07:09 PM
heater cores are easy! :banana:

03-07-2005, 03:09 AM
how will i know if it goes bad?

will it do like my truck and start leaking coolant all over the passenger side floor?

I have seen some worse examples explode and vaporize all vegetaion and animal life within a 13-mile radius...

04-09-2006, 11:53 PM
I had a friend in high school who wrecked when his popped on him. He said one minute he is flying down this narrow little country road, (barely, one lane)having a blast, then there is a pop sound. The next instant the car is full of steam and the windshield fogs up in a matter of seconds.

He got slowed down, a bit, and managed not to hit any trees, but he slammed his right front fender and wheel into a monster of a rock. It struck forcefully enough to break the ball joint and twist up the lower A arm like a pretzel.

He didn't get hurt or anything, but it shook him up pretty good. He later told us he had been smelling coolant for a few days, but thought it was comeing from somewhere under the hood.

BTW, it wasn't a box body. I want so say it was a late 70's full size ford, but I really don't remember.