Safe to bypass heater core?

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Is there anything I should be aware of when bypassing the heater core on a '95 Grand Marquis? The core has started leaking a bit and I thought I would just short-circuit the hoses before they go through the firewall as a temporary fix until I have the time (looks like an all-day job) to take the dashboard off to get at the heater core. Since it's summer I'll be using the air conditioning, but I can live without heat for awhile.
 
There is no problem bypassing the heater core, I would do the same thing...just make sure you remember to fix it before the snow flies.
 
Certainly is. When I bought my 93 Crown Vic, the guy told me he spent I think it was something like 600 bucks just to replace the heater core because the whole dash had to come off. Taking the heater core out of circulation during the warmer months is a viable option
 
Faloln_LS posted pics of his dash all apart. Intimidating pictures!

Just be sure you note one hose is probably bigger than the other.
 
We did one on a late 90's Taraus. The owner came back 2 times afterwards for noises behind the dash. When you take THAT many screws off at the sametime and just let the dash hang down on the front seat there will be squeaks afterwards. But, it was a 1 day job. It's doable.
 
I wonder if plugging the two hoses might be a little better. That would send more water thought the block rather than bypassing the block through the shunt.
 
I'm assuming it's the heater core that's leaking as I can smell coolant, and there is coolant dripping down from somewhere below the area where the condenser is on the engine side of the firewall. But, there is no coolant leaking into the passenger compartment. I assume there must be a drain of some sort connecting the heater housing through the firewall. Or, could it be something else leaking?
 
On the OP's 95 I'd not be worried.

BUT for other vehicles the heater core is a important part of the WHOLE cooling system and taking it out of the system could cause more issues with keeping the engine cooled.

Bill
 
Originally Posted By: AuthorEditor
I'm assuming it's the heater core that's leaking as I can smell coolant, and there is coolant dripping down from somewhere below the area where the condenser is on the engine side of the firewall. But, there is no coolant leaking into the passenger compartment. I assume there must be a drain of some sort connecting the heater housing through the firewall. Or, could it be something else leaking?


There could be a drain, or something else can be leaking. Before I invested the time in swapping out a heater core, I would make sure its connected and pressure test the system first, and have a good look for leaks. You might luck out, and find something as simple as a connection, clamp, or hose.
 
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BUT for other vehicles the heater core is a important part of the WHOLE cooling system and taking it out of the system could cause more issues with keeping the engine cooled.


That's interesting Bill. My guess would be that the Crown Vic/Grand Marquis radiator/fan is big enough to provide plenty of cooling, but I have wondered about some current cars that seem to have miniature cooling systems. Can't remember what I was looking at but the fans looked like something out of a computer.
 
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Before I invested the time in swapping out a heater core, I would make sure its connected and pressure test the system first, and have a good look for leaks. You might luck out, and find something as simple as a connection, clamp, or hose.


It's definitely leaking coolant (green, smells, feels like coolant), and I can tell from the general vicinity it is about where the drain would be for the plenum box, and I can't see what else it could be without getting underneath the car. All coolant hoses etc. in that vicinity seem to be fine when looking from above. Also, I can smell coolant pretty strongly in the car when the fan is on.

But, you are right, I will put it up on the ramps and try to see better where it is coming from before I pull the dash to replace the heater core.
 
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what engine?


My '95 Grand Marquis has the standard 4.6 V8. I don't think there was any other engine available.
 
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Originally Posted By: AuthorEditor
I'm assuming it's the heater core that's leaking as I can smell coolant, and there is coolant dripping down from somewhere below the area where the condenser is on the engine side of the firewall. But, there is no coolant leaking into the passenger compartment. I assume there must be a drain of some sort connecting the heater housing through the firewall. Or, could it be something else leaking?

The condenser is nowhere near the firewall. It's in front of the radiator. You mean the evaporator?
 
Originally Posted By: brelandt
We did one on a late 90's Taraus. The owner came back 2 times afterwards for noises behind the dash. When you take THAT many screws off at the sametime and just let the dash hang down on the front seat there will be squeaks afterwards. But, it was a 1 day job. It's doable.


Off Topic. There is a "work around" posted on You Tube that eliminates many hours of work on the Taurus heater core replacement. http://www.youtube.com/watch?v=LsZoFoiJsdw

I always check You Tube now for short cuts.
 
Originally Posted By: Bill in Utah
On the OP's 95 I'd not be worried.

BUT for other vehicles the heater core is a important part of the WHOLE cooling system and taking it out of the system could cause more issues with keeping the engine cooled.

Bill


I'd be more concern that a car has cooling system dumping heat forcefully into the cabin. It will be uncomfortable. If you can stop that with a driver controlled valve, then it is not going to be useful as a cooling system.
 
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The condenser is nowhere near the firewall. It's in front of the radiator. You mean the evaporator?


Sorry, I meant the accumulator. I always get those terms mixed up.
 
Originally Posted By: AuthorEditor
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what engine?


My '95 Grand Marquis has the standard 4.6 V8. I don't think there was any other engine available.


Correct, only engine available in ANY '92-'11 Grand Marquis, or Crown Vic...

It's a 99.99% the core is leaking and dribbling out the A/C drain... You can loosen the pressure cap and probably stop most of the leak, as long as the cooling system is in good shape there won't be any issue... I ran my '93 for three or four years with a loose cap cause one of the crimps on the radiator tanks was seeping...
 
Bypassing is good and safe.
But you have one of the worse vehicles to replace the HC in!
They should be horsewhipped for doing that to us!
 
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