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heater core failures...possible causes?

11K views 20 replies 8 participants last post by  WinginIt 
#1 ·
Another stupid question. I have posted my heater core problems before and I'm here again... I have a '97 4.6. My baby has eaten THREE heater cores in the last 18 months!! Number 1 I paid for, number 2 (three months later) was under warranty but my dealer said that my radiator had a leak and THAT caused my failure. They agreed to do the core under warranty and I had to pay for the radiator. Number three was just last March and I had to pay as I had gone past my 12k warranty.


On this last one I asked them WHY the core had ruptured and they couldn't (wouldn't??) tell me. I just want to know because it seems to me that broken heater cores could be a SYMPTOM of a different problem. Could it be that my dealer "screwed the pooch" on my core installs and will not admit it, or is there something else that causes this and they aren't seeing it. The cores usually go in the winter time or when temps here in central Tx are in the 40's-50's.

I also have spoken to Ford Customer Service and they have no clue either. (and they will not call me back)
 
#2 · (Edited)
Yeah....I can tell you the.....

contributing reasons for your heater core failure...

1) poor manufacturing quality

2) higher cooling system pressure at high rpms
than the core can easily withstand.

3) MOST IMPORTANT - Cooling system electrolysis.
Have it checked , or do it yourself. If it's
more than .4 volts you need additional grounding.
Electolysis can eat away water pump vanes also to
the point where the pump is no longer able to provide
adequate circulation for the cooling system - I've
seen it with my own eyes so don't let some service
writer schmaltz you into thinking that it doesn't
happen - because it does. If you're told it's not
possible, I can put the dimwit in touch with a VERY
sharp Head Service Manager at Ford who's familiar with
the problem.

Good luck,
 
#3 ·
electrolysis...

yep they said that could be it but they had NO fix for the problem. I added some of Redline's "water wetter" when I got my baby back the last time. It is supposed to prevent electrolysis. I'm still worried though, I cannot afford another failure!!
 
#5 · (Edited)
There IS a fix, it's......

multiple additional grounding straps. Keep adding 'em
'til the voltage drops....block to chassis, heater core
housing or motor or mounting bolt to chassis, radiator
to chassis. ALSO using distilled or RO water may help
as dissolved electrolytes are removed. Don't give up.
You might want to consider the water pressure restrictor
used in some earlier Ford vans in the heater core line
to control over pressure at high rpms.

Good luck,
 
#6 ·
Well...it MIGHT mean...

JJanney said:
When I bought my bird the heater core was disconnected... Still is... Bad Thing?
the heater core's bad. That's usually why people
disconnect them....I hope I'm wrong. :confused:

Good luck!
 
#8 ·
IF it is, in fact, bad....

and you want to be able to have heat in your car
(maybe you don't care living in Florida) when
it gets cold, then you'll have to replace what
we're assuming is a leaking heater core.

As far as proper engine function is concerned,
it's not necessary to have an operating heater.

Hope this helps,
 
#9 ·
A lot in fact, it might explain a leak that I am having. I noticed back by the heater core cables, a small leak of coolant. Could that be it?

Haha, and yes, I'm not terribly afraid of the cold here in Florida. I'll just stay inside on frigid nights.

Thanks a lot for your expertise

Jeremy
 
#10 ·
Expertise.....?

not much of that, I'm afraid....but a small amount
of experience and a LOT of reading on this board. Thanks.

Normally speaking, heater cores leak onto the carpeting
in the passenger side footwell. Even if it's now dry - try
sniffing it near the firewall and see if you detect the
odor of anti-freeze. That's not to say it might not be
leaking somewhere around the heater core hose connection
and out into the engine compartment.
 
#12 ·
hey Mav...

Hey Mav, Jrb23 (originator of this thread) here, I am going on 5 months on my third core. This time out I put Redline "Water Wetter" in my coolant. Here's the link:

http://www.steeda.com/store/-catalog/redlinewater.htm

It is a "surfacant". It is supposed to prevent "electrolysis", which eats away at the cooling system. Since I put it in I have noticed slightly lower coolant temps. It can't hurt so give it a try.
 
#13 ·
Hmmm...

jrb23, cool, thanks! Talking to one other person today, they said it could be that electrolisys stuff... Bah... plus the system had the wrong coolant a while back, so my coolant system is all screewed as it is!

Since the smell of anti-freeze and clouds of stinky, white smoke started getting me buzzed while driving today (and making me sick to my stomach), I bypassed the heater core with a piece of hose... The $1.49 fix eliminated the smell and windshield fog, however, after doing so, my 'bird runs really bad at less than 1000 RPM. It stalled a few times and the oil pressure needle was in normal, but sitting lower than it normally does for a few minutes... I don't have a clue why it would do all that, but I think it might have had something to do with getting the anti-freeze all over the rear spark plug...
 
#14 ·
My car is leaking coolant all of a sudden...

its coming from somewhere on the passenger side, under the dash, closer to the window side of the car. Does this mean that my heater core is done for? Am I going to have to get a new one if I want heat in the winter? Also, about how much would it cost to get fixed?

btw, it's a '93 3.8lx

thanks guys!
 
#15 ·
Sounds like it is the heater core. I never experienced a wet floorboard, but I was able to smell it and after a short time, got allot of moisture and stinky, white clouds fuming from the air vents.

If it is infact the heater core, it will definitely need to be fixed to get heat (and to keep driving the car with coolant if it gets that bad). Remember, no heat = no defrost too!

I had mine fixed twice (second time under warranty) in 6 months, and it cost about $1000 because they had to remove the dash, unhook all my custom alarm and radio equipment, evacuate the A/C and replace the heater core. For a normal replacement, I was quoted around $750.
 
#16 ·
awww...man...

shoot... can i put in some stop leak stuff and would that work? cuz i definitely don't have $750 available...

is there any way to make this fix cheaper?... i guess i could bypass the heater, but...it's getting a bit cold here in New York.

also, if i definitely have to get a new one, is there an aftermarket heater core available that's more reliable than the stock one?
:(
 
#17 ·
i've seen the electrolysis deal with my own eyes as well. a 97 dodge neon with a blown head gasket had gaping holes and dips in the aluminum head near the water ports. had to have the head machined to make sure the customer didn't blow another head gasket anytime soon. it was the first time i saw such a thing, but chemically it makes sence. the rust inhibitors and the ethylene glycol which make anti freeze what it is, chemically react to scale and rust in the cooling chambers of the block and head. the constant swapping of electrons in the valance shells of each independant chemical are enough to make a small current. (current is electron flow) the same thing happens in the lead acid battery found in your car. the transfer of electrons between the lead sheets, and the sulfuric acid/water mixture.
 
#18 ·
Your options...

You can try some stop leak stuff, but your results may vary. When I had mine replaced, they where glad I had not dumped anything into the coolant. Personally, I don't like to idea of putting a band-aid on a broken leg as a permanent solution.

You could replace it yourself. I think there's an article around here that describes the steps to do it, without evac'ing the AC. It's an all weekend job from what I've heard.

I looked into better replacements and asked around, and no one had a good answer. Most of the part places just claimed their replacement model was better than Ford's factory part...not like I expected them to say anything else.

The second time it broke (a few months ago), I spent several hours searching the internet for electric heater core replacements. Something I could rig up to replace the coolant one... but I found nothing helpful, other than a few parts available for building all electric vehicles.
 
#19 ·
Well, I think I have the record for the most blown heater cores in this club. I just had my 6th replaced a couple months ago. Thats SIX in about the same 18th month span as your 3, so you can imagine how frustrating it is. The main reasons they blow seem to be a combo of more pressure then the core can withstand at a high rpm, and very poor heater core quality. At the rate mine were blowing, there wasn't enough time for electrolysis to be causeing the problem. I went threw 2 cores even after it was grounded for electrolysis.
So, at this last visit to Ford, I had them replace the core with a non-Ford part since its obvious that they don't have a very high quality standard on their cores. Also, they installed a restrictor on the inlet side to keep the coolant pressure at an acceptable level at a higher rpm. Hopefully it holds togther for a couple years now.
 
#20 ·
I agree with you, it is probably high pressure on mine too. When the replacement failed, they checked my engine for all kinda stuff including a blown head gasket, bad coolant and even pressure. They came up with nothing, other than the "replacement was defective". I just hope the 3rd times the charm for me! :D
 
#21 ·
I have been dealing with heater cores since the mid-'70's. On Classic Mustangs before I had the "84 bird. I agree with most of what was offered as possible problems, but I want to add one more. If you happen to be doing something else under the hood, and try and move the heater hoses even a little bit to get some clearance, you will most likely cause the outlet and inlet tubes to crack at the solder seams. I've had this happen to mine, I know, and right before I could warn my bud not to move them on his "90 'Stang, he did it to his. Well, I can't approach some of your records with this being my 3rd in this car since I have had it, but I decided I was tired of taking all day and taking the dash out. Since I was a sheet metal mechanic by trade, I decided to cut a hole in the firewall and side of the heater box, then the core can just be slid out. The new core is in, but I am in the process of making the cover panel. I am also going to brace the hoses to a bracket that will keep it from moving in any other way than the core moves by using the bolt that holds the heater box in, and some other bolts I may have to install to the heater box through the hole I cut. I am new to this site, don't know if there is a place to post step by step pix, but if so maybe someone could give me some instructions. Otherwise, I plan to post them on Yahoo pix, probably. I'll keep y'all informed on how it ends up.

Good luck,

Bob
 
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