Method for Removing Heater Core on Firewall for 55th

Discussions related to engines, transmissions, rear axles, suspension & steering.
Post Reply
JPGoebel
Posts: 14
Joined: Wed May 29, 2019 1:33 pm

Method for Removing Heater Core on Firewall for 55th

Post by JPGoebel » Mon Jun 03, 2019 6:31 pm

Hello All,

In endeavoring to replace the head gaskets on my 1955 Patrician, the manual calls for removing the heater on the passenger-side firewall. I've spent an entire afternoon trying to figure it, but I can't see how to get it off. The manual says three bolts hold it to the firewall, but I can't see how to get at them. The heater cover won't come loose (it seems to be riveted on the back) and I'd hate to have to remove the "plenum" on the inside.

Is there something I'm overlooking?

Many thanks in advance,

JPGoebel

Dave Czirr
Moderator
Posts: 4961
Joined: Tue Jun 16, 2009 5:30 am
Location: New Jersey

Re: Method for Removing Heater Core on Firewall for 55th

Post by Dave Czirr » Tue Jun 04, 2019 4:31 am

You need to remove the plenum first to get at them, and that's not a particularly difficult job.

Howard56
Posts: 1117
Joined: Mon Dec 24, 2012 11:35 am

Re: Method for Removing Heater Core on Firewall for 55th

Post by Howard56 » Tue Jun 04, 2019 6:17 am

The top of the box does not need to come off and at any rate will not do so without removing the entire assy from the firewall and then taking out a couple of small screws on the back side.

Dave is correct on needing to remove the plenum from 48-54 but on a 55-6 the bolts holding the heater assy are all accessed from the engine compt. There should be three 5/16 hex head bolts (on some units, large round head screws or a combination) holding the box and the round duct portion below the box containing the flapper valve to the firewall. Depending on when your 55 was made there will probably be another thin L shaped brace welded onto the top inner edge of the box portion which has a sheetmetal screw holding it to the firewall. The box and round tube are held together as an assy by a large plate welded to both which creates a space between the box and tube. The molded heater hose from the block outlet to water valve and a portion of the wire loom will probably run thru that space and will need to be removed so the assy can come off the firewall. The wire loom may have been routed in other locations above or below the assy but the hose is probably going to cause the problem.

To remove the entire assy, verify if you have the hose or wire loom running in the open space under the box. If so disconnect the block hose from the valve or head and if needed, the wire loom from the generator, regulator, head light terminal strip plus a couple of inline connectors and pull them thru the space. Also disconnect the two hoses on the box going to the heater core and the large duct hose connected to the round tube. On the fender side of the round tube portion there is a Bowden cable that works the air flapper. There is a small round push nut holding the cable operating wire to a metal stem coming out of the tube. The push nut will usually come off if you twist and pull at the same time but on occasion does need persuading. Take care not to break the tiny tangs which grip the stem or you will need to find a replacement. The cable housing is held by a clamp and screw to a bracket welded onto the tube. Remove both screw and push nut so the cable is freed from the assy and then remove the bolts and sheet metal screw holding the entire assy to the firewall. The gasket may be stuck to the firewall but if not, once the bolts are out the unit will be free and want to fall away. It is fairly heavy so be prepared.

Here is a photo and illustration from the parts book. The arrows show the approximate location of the bolts and sheet metal screw holding the assy to the firewall.
Attachments
firewall.jpg
heater.jpg

Dave Czirr
Moderator
Posts: 4961
Joined: Tue Jun 16, 2009 5:30 am
Location: New Jersey

Re: Method for Removing Heater Core on Firewall for 55th

Post by Dave Czirr » Tue Jun 04, 2019 7:17 am

Sorry about that JPG, I've removed heaters from many postwar cars but it was many years ago, I forgot the distinction about the 55/56 units.

Howard56
Posts: 1117
Joined: Mon Dec 24, 2012 11:35 am

Re: Method for Removing Heater Core on Firewall for 55th

Post by Howard56 » Tue Jun 04, 2019 8:27 am

Once you have the assy off the firewall I would suggest removing the two small sheet metal screws on the rear side next to the firewall. There are enough screws holding the parts together on the other 3 sides so you can leave them out. Cover the holes with tape if you wish. By leaving the screws out, if you need to remove the core at some point you can remove the top half and lift the core out without taking the entire unit off the firewall again.

JPGoebel
Posts: 14
Joined: Wed May 29, 2019 1:33 pm

Re: Method for Removing Heater Core on Firewall for 55th

Post by JPGoebel » Tue Jun 04, 2019 10:18 am

A thousand thanks to you all! This is by far the most knowledgeable and helpful community on the entirety of the internet! I'll have it apart by this evening, I reckon.

Howard56
Posts: 1117
Joined: Mon Dec 24, 2012 11:35 am

Re: Method for Removing Heater Core on Firewall for 55th

Post by Howard56 » Wed Jun 05, 2019 7:42 am

Glad to help and good luck. Lets hope the headgasket cures the problem.

On the short heater hose between the block and valve, there is a good chance it will give you grief or be damaged when you mess with it. If it is the old original hose or maybe one that was changed years ago it should be changed. Ordinary straight 5/8 hose can be used but that requires a longer length and different routing to avoid a sharp bend where it connects to the valve. Randy Berger who usually posts at the packardinfo forum found a modern molded hose available from Napa or other parts stores with the correct bend. You can trim the ends of the new hose to fit and perfectly replace what was there from the factory.
Attachments
molded heater hose repl.jpg

JPGoebel
Posts: 14
Joined: Wed May 29, 2019 1:33 pm

Re: Method for Removing Heater Core on Firewall for 55th

Post by JPGoebel » Thu Jun 06, 2019 6:47 am

Thank you again, this is brilliant! I removed the heater successfully, and have sent the heads out to be milled. I should have it back together in short order!

Two of the heater cores, the front and left rear, leak. They weren't even hooked up. I'll likely remove them and have them mended before I set up the hoses, but grand to know how to do it now!

Howard56
Posts: 1117
Joined: Mon Dec 24, 2012 11:35 am

Re: Method for Removing Heater Core on Firewall for 55th

Post by Howard56 » Thu Jun 06, 2019 10:25 am

One other thing known to leak is the heater thermal valve and sometimes that leak has been misdiagnosed as coming from the heater core. The valve leak will typically show as damp carpet on the passenger side and/or water dripping from under the car somewhere near midpoint on the right side. The area is not specific because as water runs down from the valve and under the carpet it can drip out one of the body bolt openings or thru a hole in a rusted floor.

The valve can be repaired and Napa has the little rubber seal that fails for around $10 + freight. It can a pain to take the valve apart but if you should find a need for a rebuild and want to tackle it yourself rather than buy a rebuilt exchange valve there is an excellent Replace a Ranco Heater Valve Seal article in the literature HOW TO & TECH TIP section at packardinfo. All the literature on the packardinfo site is available for free download.
Attachments
Ranco Seal.jpg

Post Reply