Joined: Sat Mar 25 2006, 07:31PM
Location: Nebo, NC
Posts: 86
I am not usually in a big hurry for answers, but this is a special case. We need to drive our '71 300 on a 400-mile trip tomorrow and the new (not used) heater core I just installed leaks like a seive! I have no time (or inclination) to do this job over again so, rather than plug it off, is there any sort of stop-leak material on the market which will do the job without turning my brand-new coolant a sludgy brown as Bar's Leaks does?
Later, when I have more time, I will share with you "Fuselage C-body Heater Core Replacement, or the secret formula for spending over two hundred bucks, about fifteen hours and untold frustration in the pursuit of accomplishing absolutely NOTHING".
Joined: Sun Feb 05 2006, 11:51PM
Location: Pa
Posts: 3064
Unfortunately, anything you put into the system will tend to plug all sorts of passages - that's why it stops leaks! I have used Bar's and then flushed the system out with the 2 part cleaner as soon as I could (after your trip), with no long term problems. The silver "powder in the tube" stuff turns to "wet birdseed" (I accidently left a tube of this in a coat pocket that went through the wash!) so I wouldn't recommend that. You could open the inlet hose for the heater and plug it with a brass slug and put another hose clamp around the outside of the hose after it's re-installed to hold it. Or shut off the control valve and take the cable off so it stays there. If you could see the leak in the core, you could put hot melt glue over it. This would peel right off later. Have a safe trip
Joined: Tue Oct 11 2005, 01:33AM
Location: Calgary, Alberta
Posts: 5893
Been there with various leak additives without much luck and as Stitch says they cause more problems. It's unusual for a new core to leak unless you opened a solder joint when pushing on one of the hoses. Are you reusing the old hoses? Maybe one of them has a split in the inner liner so if you have enough length, chop off a couple inches and try again.
Joined: Sat Mar 25 2006, 07:31PM
Location: Nebo, NC
Posts: 86
I would never re-use an old heater hose. On '70 - '71 Chryslers (and I suspect all fuselage C-bodies) you have to remove the R.F. wheel and inner fender just to get to the actual heater core hose connections, so I replace those puppies every chance I get. They are brand-new with plenty of slack and screw-type hose clamps, tight but not over-tightened. I was in no way rough during the course of re-installing the heater core (or perhaps I should say "reassembling the car around it"). BTW, I recommend using some windshield installation tape as sealer when reassembling the heater box.
Just try to buy a heater core for one of these cars. Rebuilding them is cost-prohibitive. I ended up buying a similar core with a different frame and having a competent radiator man fit it into the old frame and graft the old tubes onto it. I think he did his job, but something must have gone wrong during my installation. I did find a leak at the soldered lower radiator outlet joint, so this may be the biggest source of my coolant loss, rather than the heater -- but there WERE some green drops on the passenger side floor yesterday.
Joined: Sat Dec 10 2005, 04:28PM
Location: United States
Posts: 4954
Hey Jeff
That can be done without taking the well out. . . The blower motor is a different story. I did a few of them from underneith. PITA, but less work.
I think I have two of those heater cores here. 71 Fury is the same. I bought a box, so I need to look. . . . Don't know what the condition is though. Lemme know and I'll look
Joined: Sat Mar 25 2006, 07:31PM
Location: Nebo, NC
Posts: 86
Well, I'm back from my 400-mile round trip to the Midlands Mopar Show in Columbia, SC and the '71 300 performed quite commendably. Since I had no choice, I gritted my teeth and rolled the dice on 16 ounces of AlumAseal Radiator Stop Leak which I poured directly into the radiator (this stuff goes in like syrup, not dry). There have been no more leaks from either the radiator hose coupler or from the heater core. Unlike Bar's Leaks, I can't tell that it's in the coolant by its appearance. And the car never ran over 190 degrees on the trip.
71F3, I think I may take you up on one of those heater cores if i'ts tight and if you really want to sell it, so PM me.. And you are technically right about the heater hoses, but I am afraid of not getting the connections tightened properly if I don't have the inner fender out. Besides, I DID want to take out my blower to see if it was any part of the low-air-volume problem. I disassembled, cleaned and lubed it while I had it out. I am now confident that, when hooked to 12 volts, it could push a Katrina-class hurricane back out to sea.
Joined: Sat Dec 10 2005, 04:28PM
Location: United States
Posts: 4954
Oh Boy. Now you tell me. I can't get into my garage attic at the moment. It'll be a few weeks. I have half a Polara stacked on the floor. BUT! I will look. I need to get up there anyway.