Fleetwood Heater Core

You should know what this is. If not, you probably roll your windows down a lot.
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Adam
Posts: 2240
Joined: Wed Oct 23, 2013 9:50 pm

Fleetwood Heater Core

Post by Adam »

Did this last weekend. I even took some (terrible) photos. Turns out the low-light camera performance on my phone is mediocre at best. The reason for this job is to remedy the poor heater performance. I have flushed the coolant once a year since I got the car and have removed a lot of rust from the heater core each time. The heat then works good for a week or so, then it gets worse. Sometimes when you first turn the heat on, you get a whiff of coolant in the passenger compartment, but there is no window fogging or damp floor usually associated with a leaking heater core. At the very least, getting all the rust out of the system should improve its performance dramatically. Judging on the condition of the coolant when I first did a flush, the previous owners hadn't done one in 10+ years, which is about the length of time they owned the car...

Step 1: Remove engine. No, wait, this isn't a Saab. Remove coolant. That drain valve actually has a 1/4" square cut in it so you can open/close it with a nut driver. You can also see the aftermarket oil cooler lines are starting to rust after only a couple of years. Should have put some paint on them.
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The rest of the coolant is drained by removing the lower heater line 'cause reverse flow cooling system. Notice how gross the coolant is. It is only about a year old. There is some RMI-25 in it, which may have contributed to the color as it cleaned stuff out.
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Then remove the heater lines at the firewall (not shown).

Then comes the fun part, lower dash removal. Some screws removes this lower plastic part. It's not that blurry in real life.
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Removed!
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Next, you can remove the 7-ish screws in the bottom of the heater box (not shown). This part was fairly annoying, as there is one screw at the firewall side that you can't see. I got better access to it by pulling the carpet back and moving some foam sound insulation out of the way. After that it came right out.

Just as I suspected! You can see the telltale sign of coolant in the bottom of the heater box.
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You can kind of see where it was leaking out of the heater core in this blurry photo.
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After some wrestling and removing two brackets, it comes right out. Then swap over the foam tape and the clamp thing on the inlet/outlet pipes and you are ready for re-installation.
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I also did a thermostat while the system was drained. The camera seems to want to focus on things that aren't in the center of the shot for some reason. I should really use the garage point-and-shoot for better quality images.
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Refill and bleed and you are good to go. The heater performance has never been better! I get heat in the cabin quickly (like a large V8 car should) and if left on high, you actually have to open a window because its too hot.

In other news, I broke some things during this install when I was removing the heater lines at the firewall. The first of which was the oil dipstick. Broke the handle right off it since it is exactly where your hand needs to be to use long needle nose pliers to remove the hose clamp. When I was removing the dipstick tube to pull the broken dipstick out of it in order to replace it with the one from the Caprice (parts car FTW!), I also broke the plastic end off the coolant switch, which is right where your hand ends up half way through pulling the dipstick tube out of the block. It doesn't leak, so I will get around to this later. It is a different sending unit for the Caprice and the Fleetwood (gauge vs. light) so I can't just borrow my spare. Oh well. There is a separate sending unit for the PCM in the water pump so I am not worried about the fans not coming on or it overheating. Add that to the list of things to do.

Turns out I have more RMI-25, so I might add another bottle to the system to help clean up anything left in there.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Fleetwood Heater Core

Post by kevm14 »

I'd put RMI-25 in there.

I've never had do to a heater core in anything and I've always dreaded it. Curious about the lower dash stuff.

The sending unit for the dash is in the passenger side head? It's on the driver's side on my L05.
Adam
Posts: 2240
Joined: Wed Oct 23, 2013 9:50 pm

Re: Fleetwood Heater Core

Post by Adam »

I've had to do a couple heater cores over the years. It's usually due to complications from lack of maintenance. If you buy nicer cars, it isn't an issue.

Yes, the dash sending unit is in the passenger side head. Same as my other '94 LT1.
Adam
Posts: 2240
Joined: Wed Oct 23, 2013 9:50 pm

Re: Fleetwood Heater Core

Post by Adam »

Once the lower plastic panel was off, the bottom of the heater box is right there. The only complication is that bolt/screw you can't see. The FSM made a specific note about it, so I was aware going in.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Fleetwood Heater Core

Post by kevm14 »

How much coolant did you spill on the carpet?
Adam
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Joined: Wed Oct 23, 2013 9:50 pm

Re: Fleetwood Heater Core

Post by Adam »

kevm14 wrote:How much coolant did you spill on the carpet?
None. There wasn't enough in the bottom of the heater box to spill out.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Fleetwood Heater Core

Post by kevm14 »

I meant any that would have been due to wrangling the heater core out of there.
Adam
Posts: 2240
Joined: Wed Oct 23, 2013 9:50 pm

Re: Fleetwood Heater Core

Post by Adam »

kevm14 wrote:I meant any that would have been due to wrangling the heater core out of there.
None. The heater core comes straight out of the firewall, then down into the passenger compartment so unless you tip it upside down, there is no chance to spill coolant.
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