Heater Core Leak

Other question: does the carpet have a plastic, waterproof backing? In other words, is all the coolant soaked into the carpet? Or is there coolant down on the sheet metal under the carpet? And do I have to remove the carpet to clean up under there?
 
This says ground to sheetmetal, no, ground to the engine block. Our body is only grounded thru a thin wire, and current flows in it, so the body is not at the engine voltage.
Get aluminum, and ground it to the engine next to the starter.
 
1997ThunderbirdLXV6 said:
Other question: does the carpet have a plastic, waterproof backing? In other words, is all the coolant soaked into the carpet? Or is there coolant down on the sheet metal under the carpet? And do I have to remove the carpet to clean up under there?
Click to expand...

There is no meaningful moisture barrier. If the carpet gets soaked, it will drain through to the floor pan. Pulling the seats is enough to get at the bulk of the area under there.
 
1997ThunderbirdLXV6 said:
Other question: does the carpet have a plastic, waterproof backing? In other words, is all the coolant soaked into the carpet? Or is there coolant down on the sheet metal under the carpet? And do I have to remove the carpet to clean up under there?
Click to expand...

If you've got the seats out I'd just pull the carpet and dry it out, inspect the floor pan, clean and prime any rust spots. It's a great opportunity to inspect the floor pan. Slap a few of these down on the sheet metal to dampen vibration and road noise. Really good stuff for not too much money. I used it to treat the floorboard of our '99 RAM 1500 when I upgraded and repaired the interior of the cab.

 
Question: Does all coolant go through the heater core, or just a portion of it?

I'm asking because I anticipate my bypass to be potentially slightly kinked, which may reduce the inner diameter of the hose. Problem?


Meanwhile, I doubt I'll be able to get the hoses off without destroying them. Add that to the shopping list.
 
1997ThunderbirdLXV6 said:
Weird. So my car has a V8 core?! I wonder if that's not even original then...

View attachment 14605
Click to expand...
Looks original to me. The rubber seal is intact. Most folks wind up cutting to get new hose ends through as it is tight going in and since they are angled doesn't help and I was always afraid I would bend/kink them and ruin the core.
 
1997ThunderbirdLXV6 said:
Question: Does all coolant go through the heater core, or just a portion of it?

I'm asking because I anticipate my bypass to be potentially slightly kinked, which may reduce the inner diameter of the hose. Problem?
Click to expand...

No, coolant takes the path of least resistance. In the case of tees and wyes, it will equalize the pressure across all pathways - so smaller diameter and complex pathways will have a higher pressure for a given flow meaning they will flow less at a given pressure, but still flow compared to larger, more free-flowing parts of the system.

Here's the page in my FSM that shows coolant flow for the 97 3.8:

PXL_20250918_150741371.jpg
 
And I asked if I could do this in one day... :facepalm:


Meanwhile, nobody commented on my excellent transmission temperatures. They're easily >40°F below what I used to see.
 
1758215021089.png

Here is my custom setup. The nipple of the intake is 3/4, the reducer is not shown in the picture

everything I used -

1758215143932.png

It may be different for the 3.8

Also the heater hose at most parts store is junk. It will work, but is much thinner and I wouldn't recommend it for a long term repair
 
Ok...I cut the lines because there was no way to get them off without a nervous breakdown:

20250918_140030.jpg

Then I used one of the old hoses, not the one I bought this morning, to form a bypass. I had to minimally bend it, so there's some minor stress on the rubber, but I doubt that's an issue (?). No idea why it looks so veiny; maybe I jerked it too much:

20250918_140044.jpg

About to fill the reservoir and start the engine. Absent any issues, I'm headed to the store for kitty litter next.
 
I think now that the rubber was hot, once the engine cools back down, I'll loosen the clamps once, let the rubber settle, then reattach the clamps. Just to minimize stress altogether.

How do they manufacture these molded hoses in the first place? Do they start with a straight hose and mold in the curves, or do they make them with the curves from the start?

Assuming this installation is secure...here's a thought: in Virginia, I use consistent heat at best one month of the year, plus some occasional heat for up to an additional two months. Given my natural appreciation for the flamboyant, I also own a collection of exquisite scarf and sweaters. How crazy would it be to just  not replace the heater core?

Meanwhile:

20250918_145553.jpg
 
Do you ever need to defog or defrost/deice the window?

When I drive the Energi in the winter, being a cheap and miserly freak of nature, I can say that I prefer to leave the heat off to maximize range with its puny battery (unless we're taking a trip that is obviously outside EV range, then I'll use the engine and heater). When the HVAC is off and no dry air is being blown over the windshield, it will start to fog up within 3-5 minutes. If you turn the defroster on and let it blow cold, dry air onto the windshield it will usually clear up. However, there are plenty of circumstances where you need heat to clear up window fog (or ice!).
 
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The situation down here is interesting. No puddles; however, the highlighted foam piece along the floor is soaked. When squeezed into a white paper towel, it was colorless; ergo, I have another moisture problem...

20250918_163345.jpg

Meanwhile, on the positive side, mid-80s today and high 80s tomorrow. So the car can bake in the sun and hopefully dry some.
 
I started lurking there in 98, when it was birdcats, iirc.
I broke the original intake on Lazarus, and bought and swapped an NPI manifold.
Someone told me how to swap it. iirc, it was Ox or Joel. RIP, Joel!
 
Ok, so I'll very likely make this repair at some point; I just decided not to rush anything. Instead I want to read and study some first.

Meanwhile, I'll keep dropping questions here as they come up.

Reading in the factory workshop manual, the firewall gasket of the heater core comes out with it and is transferred to the new heater core. Yet, in the instructions in the tech article, it seems the gasket stays in the firewall (?); or am I misunderstanding something?
 
1997ThunderbirdLXV6 said:
You know where the tech article  does have its photos showing? On TSTSNBN!
Click to expand...

Probably because @XR7-4.6 copy/pasted the inline images along with his text which had references to embedded graphics that didn't paste with over here. He'll need to go and manually copy/reupload all his pics. :)
 
1997ThunderbirdLXV6 said:
Ok, so I'll very likely make this repair at some point; I just decided not to rush anything. Instead I want to read and study some first.

Meanwhile, I'll keep dropping questions here as they come up.

Reading in the factory workshop manual, the firewall gasket of the heater core comes out with it and is transferred to the new heater core. Yet, in the instructions in the tech article, it seems the gasket stays in the firewall (?); or am I misunderstanding something?
Click to expand...

The gasket is sandwiched between the firewall and the heater box and larger in size than the hole the core passes through.
 
theterminator93 said:
Probably because @XR7-4.6 copy/pasted the inline images along with his text which had references to embedded graphics that didn't paste with over here. He'll need to go and manually copy/reupload all his pics. :)
Click to expand...

I didn’t write that article so I don’t have the pictures saved anywhere. Even at TSTSNBN it’s a copy/paste of what used to be a members page

Gordon’s video is better anyway
 
I probably have the member page saved in my 2009 archive. Let me take a peek...

Edit - nope, not coming up. :(
 
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