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One thing leads to another 1968 DVC Climate Control

Started by cadillacmike68, October 31, 2019, 09:02:12 PM

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cadillacmike68

So, I was able to wire up a rocker switch to shunt voltage to the compressor when the Climate Control is On as noted in this thread: 

http://forums.cadillaclasalleclub.org/index.php?topic=156768.0

I did this last week and took the car to Daytona for the weekend to see Tony C and go to a couple informal shows over there.

The weather was disturbed, very humid with 40% chance of rain.

Of course it started raining heavily before I had even gotten 25 miles so I had to pull over and put up the top. I turned on the Climate Control and within a few minutes everything was fine in the car.

It was a 3 hour tour - er, um drive. Actually closer to 4 hours. I had the XM on and was just chillin - literally during the entire length of I-4. It got a bit too col so I upped the temp a few degrees, just a few from around 70-71 to 73-74.   

As the system adjusted, the dash vents started misting. I'm like WTF??

Then I sniffed it. A faint odor of Coolant.

Oh no.

So I fiddled and diddled with it over the next couple hours. As soon as it got to equilibrium, and started to blend in heated air, it would mist out of the dash vents. When I flipped it over to Fog and upped the temp to 80 + I got a Lot of mist out of the defroster vents Yikes! Lowering the temp to make it not blend heated air stops the misting. snce it never dropped below something like 78F all weekend, the misting was not an issue, because i rained again on say for a while. Sunday it was clear so I drive back with the top down and gior a little red on the left side of my face, the result of driving SW for 3 hours in the early afternoon.

SO I started thinking back to last winter when I would see condensed steam on the inside of the window on cooler nights even if I had not run the Climate Control at all and came to the conclusion that I have a heater core that is going bad. I don't have a puddle on the floor, but then this year system might not leak onto the floor. I don't have and puddles on the garage floor either, so it must be a pinhole leak. Just enough to get moisture in the air flow and make a barely detectable coolant odor in the car.

Do I have a heater core leak or a malfunctioning heater  / water control valve? My past experience with bad heater control valves is that they suck coolant all through the vacuum system of the climate control, so I don't think it is the valve.

Does anyone else have any different ideas?

I ordered a new core Spectra Premium brand, the same brand that makes the fuel pump assembly for my 1996 Fleetwood. amazon had the best price. It arrived today, made in Mexico (not china Yay!) and looks fine. 

According to this thread, it should not be that difficult to have it changed:

http://forums.cadillaclasalleclub.org/index.php?topic=146688.0

Now, how do I get any coolant residue out of  the ducts? I can clean the heater core casing myself when it's out but I'd like to get those defroster vents cleaned out. Any suggestions?

And I still have to repair or replace the bad vent switch in the control unit.


Regards,
"Cadillac" Mike

"Cadillac Kid" Greg Surfas 15364

Mike
I’ve changed “a few” heater cores and unless you were really pouring liquid into the air stream, any residual coolant in the ducts will be minor. I personally have not done anything but pull the diffusers and got back as Fay as I could from that side. Any coolant in the heater core box will drain with the condensate.
Greg surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

cadillacmike68

Greg,  I was thinking of spraying some lysol into the cowl with the fan on HI or ICE for a bit one I get it changed and cleaned up as best I can.

Then I plan to take a small sponge "bottle brush" and wipe down the inside of the defroster vents as much as possible The dash vents should be fine.
Regards,
"Cadillac" Mike

bcroe

Based on failures, I change out heater cores at 19 years.  My
Eldo/Toro being the worst, inside the car.  Bruce Roe

cadillacmike68

Regards,
"Cadillac" Mike

Scot Minesinger

Mike,

When you replace the heater core, which is easy BTW follow FSM, be sure and allow that dissimilar metals are not in contact.  The factory accomplished galvanic corrosion protection with paint.  I think that is kind of crazy, and I use a thin gasket material in addition tot he painted coating.  It fits a little tight back in the mounting, but it will last the rest of the life of this Cadillac.
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty