Replacing heater core on the Lifeliner

Bill Leverett

Bill Leverett

PCS Member/Super Site Supporter/Paramedic Supervis
Anyone have experience in replacing the front heater core on a '73 Cadillac Lifeliner? The service manual says the dash/instrument top needs to be removed in order to access the heater components. Any tips or other issues I should be concerned about?
 
Is the core leaking or is it clogged? Getting the dash top off isn't much of a problem, but it takes some effort to get to the center bolt in the front. You need to remove the glove compartment lining first. I have done them on various cars, and each time there is always something different about each of them that makes it a new learning experience. It is a time consuming job, but not a difficult one. Some come out from the passenger compartment side, and others you need to take apart the heater box on the engine side. Usually the shop manuals are not a lot of help with this project. Take lots of pictures of where things go, and if you disconnect any linkage, mark it with some nail polish so when you put it back, you have a reference point to go by. Do the same with all vacuum hoses, marking them with numbers on masking tape and a matching number on the vacuum pot itself. You will also need a box of band aids because you are bound to encounter some sharp edges... :smiley3:
 
Thanks Paul...it leaks. The mechanic who worked on the vehicle prior to me getting it actually bypassed the front heater completely due to the leak. Not sure how bad but will see when I take it out. I have no idea what shape the rear heater is in.

I've gotten smarter working on these now...I wear mechanic gloves and keep the skin on my hands and fingers!
 
got into this on a 74 just a bit ago. they want you to take to top of the dash off so you can pull the tube that goes to the sniffer just over the glove box.
the top comes off easily enough getting the vents out is the only hard part. they pry out from one side with a thin blade and a hook . the blade to lift the tab the hook to pull it to you. there are screws or bolts behind them. I can't remember which. you need to get in there and change out half the bulbs in the dash anyway. the housing drops out with 4 nuts under the hood. it falls to the inside leaking antifreeze all over. the core is right there 2 speed bolts and a strap hold it to the housing. the core is about 80 bucks an any parts store. about a week end on the first, 1/2 a day on the tenth one. I'm not sure if you need to take the top off I think you can reach everything you need to get off threw the glove box but it's your call on that. the lower right nust is the hard one to get off. you can tell if a shop did it the last time they always leave that one off.
 
Got it out.

With the helpful guideance of Paul and Ed and the shop manual (that helps with the dash removal instructions), I got the heater box off and the core out. The dash top does need to come off in order to reach all of the attachments from the top. Found the heater core leaking where one of the tubes goes into the shell. Droped it off at the rad shop and it should be ready on Tuesday. Here's a picture of what the dash looked like following the removal. The foam filters are disintegrated, should I replace these with some other foam?

On another note, in the other picture is a heater valve of some sort. The mechanic also bypassed this so I'm not sure what it's for, however I'm guessing it's a valve for controlling the flow to the rear heater. There is a cable through the firewall into a push/pull knob that's fastened just underneath the dash. Is this indeed a control valve for the rear heater? If so, why are there 3 places to connect to?
 

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When you find out about that valve with the cable, let me know. I have the same thing and not sure what is is either. Floor pan looks solid even though has a rusty color to it.
 
its for rear heat
if you look in it and the way the valve works inside it will bypass the rear heater hose but still run the front and return to the motor
 
Passenger floor pan needs replacing

Hi Richard, actually the passenger floor pan needs replacing. The rubber floor mat had deteriorated allowing water to collect in the thick underlay. I'm sure few crews actually lifted the mats up to air out the insulation.
 
that was the one they used on the MM. as they said water in, out the top to the cab heater by way of the factory valve. the other down to the rear heater. the return line should have been a y pipe in the big hose going to the raidator.
 
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