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61 ragtop,2 67 eldos,68 ragtop,68CDV,93 ETC
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Re: Replacing Heater Core 91 DeVille—Any advice?

I just did the heater core on my 90 fleetwood tuesday and the only difficult part was removing the spring clamps on the hoses. I have a tool for removing them which has a cable with a sliding jaw clamp at one end and a squeeze grip at the other. I don't know how I could have gotten them off without it. As far as the heater core itself, it was a cake walk.

1. Drain engine cooling system.
2. Heater core inlet/outlet hoses.
3. Right sound insulator.
4. Glove box module.
5. Air mix valve link.
6. Programmer vacuum and electrical connectors.
7. Heater core cover with programmer attached.
8. Heater core retaining screws and heater core.

I took the programmer off the heater core cover just to give me some more room but I don't think you would have to. I also did not drain the cooling system as very little coolant leaks out if you raise the hoses above the engine after removing them. Flat rate on this job is 2.7 hours and I think I had almost 2 into it by the time I was done. Also, when you put it back together you need to adjust the air mix door which is hooked to the threaded rod you removed from the programmer . The procedure is:

1. Remove glove box module.
2. Set temperature on Climate Control Panel (CCP) for 32°C (90°F) . Allow 1 to 2 minutes for programmer arm to travel to maximum heat position.
3. Snap threaded rod from plastic retainer on programmer output arm.
4. Check air mix valve for free travel. Push valve to maximum A/C position, and check for binding.
5. Pre-load air mix valve in maximum heat position by pulling the threaded rod to ensure the valve is sealing. Programmer output arm should be in maximum heat position.
6. Snap threaded rod into plastic retainer on programmer arm. Avoid moving programmer arm or air mix valve.
7. Set temperature on CCP for l6°C (60°F) . Verify the programmer arm and air mix valve travel to the max A/C position.
8. Install glove box module.
These are actually far easier than most heater cores these days. Good Luck!
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