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Discussion Starter #1
Hello. I just found this forum and have a question about replacing heater core in my 1990 Sedan De Ville. Is it easily accessible, or is this one that the whole dash has to come off?
Any help or other advice would be great.

Thanks, :worship:

Rick
 

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Im not sure..... I remember one (the fleetwood if I recall) heater core is super easy to get to, and it seems every one else is a PITA to replace..... Do a search.....

How do you know you need a new heater core???
 

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Discussion Starter #3
I took to Cadillac dealership. That's what THEY say it is. I'm not sure.
I have no heat. The air conditioning works. I'm not getting the "normal" signs of a bad heater core. There's nothing leaking inside the car, it isn't fogging up the windshield and I don't smell coolant.
(that's my understanding of how you can tell, anyway)

Cadillac mechanic says heater core is clogged.

I have a Haynes manual for my car and from what I read & see, this doesn't appear to be that big of a deal to change. I guess I'm looking for someone to verify that, or to tell me I'd be better off having a mechanic do it. My search has led me to; "it could go either way".

Rick
 

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Discussion Starter #4
Oh, I should also mention that dealership attempted to flush out heater core, but "couldn't get anything to come through".

Rick
 

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Hmmmm..... It must be pretty bad then..... How well has the cooling system been maintained????

Since your willing to DIY replace the heater core (right??), you seem fairly mechanically inclined...... What I would do is try and flush it out good......

Undo the in/out hoses, and put a hose going from the out hose into a bucket.....

Try and stick a garden hose upto it (ideally it would be best if you could make something with a fitting so you dont spray everywhere).... if you get any flowing from the out, your golden..... I saw that someone on caddyinfo used CLR or limeaway to get all the crap out from in there.... He let it sit for a while, and sloshed it around, and then flushed it out good.......

Id try that first.......

If you dont get anything coming out of the exit hose, then I guess your SOL and youll have to replace it.....
 

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Discussion Starter #6
I'm not sure how well this car has been maintained. I bought it this past April from my father-in-law. The most I know is that it sat for a while un-used. Elderly lady passed away and her son sold it to my father-in-law. I'd say not very well, because I've had to replace brake pads & rotors and have the transmission fluid replaced,as well as A/C work done.

I'll try the CLR or Lime-away and see what that gets me.
If not, I'll jump in with both feet & see what kind of job this will be.
(I'm not about to pay the $550.00 the dealership wants to do the job!) :helpless:

Thanks,

Rick
 

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If they want $550, then I would bet that it's not as involved a job as some of the older ones were. I bet you can handle it, and I bet it's not that tough. Get a new one and let us know how it comes out.

Good luck!
 

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Discussion Starter #8
Heater core replaced. Very easy to get to. Here's how I did it:

Disconnect negative battery terminal. Drain radiator. Disconnect heater hoses to heater core at fire wall. Remove glove box & electrical plugs for trunk release & light bulb (and fuel door switch if you have that). Remove lower sound insulator panel below right side of dash. Remove the rod from the programmer to the blend-air door. (squeeze connector & lift rod out) Disconnect electrical & vacuum connectors from the programmer, just to the right of the heater core housing.
Remove two (upper & lower) heater core cover screws & take out the heater core cover. Remove two heater core bracket screws & slowly take out the heater core, being careful not to spill any coolant that may still be in the core.

To install new core, do everything in reverse.

Took me about 3 & 1/2 hours start to finish, but someone more competent could do this in considerably less time. Tight squeeze getting upper & lower heater hoses off & on. The locking hose clamps didn't help matters. I replaced them with the screw tightening type clamps.

Hope this helps someone else.

Thanks to all for your suggestions. I got heat, baby! :D

Rick
 

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Great write up..... Very useful...... I guess your car was the easy one..... :thumbsup:

Did you by any chance take pictures.....???
 

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Discussion Starter #13 (Edited)
You know, I didn't think to do that until I was done with it. :banghead2 I wish I would have. If you think it would help, I could probably come up with some pictures. Wouldn't take that much to take apart to show the important spots. Screw locations, where the rod goes into programmer, electrical & vacuum connections, location of heater hoses, as well as the heater core itself.

The best advice I could give is to get a Haynes repair manual for your car. I've gotten one for every car I've had and they're loaded with information & pictures for just about any repair you'd want to do.
You can get them at AutoZone for $19.95 or direct from www.Haynes.com They even have them on CD, now. (I hope that's o.k. for me to give them a plug) Even a not-so-mechanically inclined person like me can understand it.

(Check me out. I'm all "Mr. Fix-it", now :histeric: )

Rick
 

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Haynes is OK..... But FSM is the only way to go IMO..... www.helminc.com
 

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Question:

Does the radiator have to be drained first?

I have a 1993 deVille and my heater core has to be replaced. Also, since I do not need a heater core to begin with, what are the consequences of bypassing the heater core permanently?

Thanks
 

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FSM sucks wes, its so damn expensive. Haynes is cheap and it has pictures. Find for easy repairs. I need to find the way to depressurize my coolant system so it doesn't blow up in my face when i take the inner fender out.
 

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RBraczyk said:
FSM sucks wes, its so damn expensive. Haynes is cheap and it has pictures. Find for easy repairs. I need to find the way to depressurize my coolant system so it doesn't blow up in my face when i take the inner fender out.
It's worth it. The manual that covers engine/trans/electrical for my 68 is an inch and a half thick. And thats for an OLD car, and not counting the body/interior manual. Gotta wonder what was left out of Haynes....

Oh, and as far as depressurizing your coolant system goes, just work on it with the engine cold, which shouldn't be a problem judging by the picture in your sig. (Doesn't look like you drive it too much as it is)
 

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All in jest. If you look in the lounge, you'll see that I am in the same situation. Anyway, I seem to remember that you have to get at the bolts from inside the wheel well, with one or two from the engine compartment. I'll try to check on my friend's 94 Concours.
 
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