Heater Core Leak

billiebob

billiebob

TJ Addict
Supporting Member
Joined
Oct 31, 2015
Messages
5,604
Location
Kootenays, BC, Canada
Last April, my heater core was leaking, took it to a shop, they put in a new one. 8 months later it is leaking again, just before the holidays. Last April, I just bypassed the heater core and drove without any heat. Not an option at Christmas. And I definitely need a defroster.

My buddy, jack of all trades, master of none said, we could loop it thru the evaporator.... which I disconnected years ago to get onboard air. It took 1 minute to trade hoses. And works like a damn. Actually since the evaporator is much bigger than the heater core it puts out way more heat. Like biggly more.... and no more leak.

No way to turn the heat off tho. Set the dial to hot, is the coolest setting since air is directed thru the disconnected heater core too. But set the dial to cool, and it pumps out way more heat than ever. Almost feels like you could burn your hand.

Anyone struggling to get enough heat, especially with just a soft top.... in Alaska or the midwest where 40 below is common..... this is a great option.

And the evaporator is built for way more pressure than the heater core.

heater core.jpg
 
Last edited:
  • Like
Reactions: Edgar Marton, StG58, MountaineerTom and 3 others
Jerry Bransford said:
Great idea, never heard of that having been done before
Click to expand...
My buddy, Rodney, is the "gitter done" kinda guy. Lots of people ride, sled, quad easy if Rodney is there. No matter what breaks, he'll figure a way to keep moving. I've seen him use a come along to tie up a broken axle/missing wheel on a pickup and drive it out like a trike.
 
My heater core is currently bypassed and replacement is on the "to do" list somewhere after the manual hub conversion and some brake work. At the rate I'm going I should probably get to it just about the time it gets warm enough not to need heat again until next fall. :(

Ingenious fix. I would try it if I lived someplace cold enough, but it's not that cold here and I have a hard top so it might turn my rig into a sauna. But I'm going to remember it just in case. . .

Does your buddy have any ideas about how to plumb valve(s) for the hoses to the heater core to bypass heated coolant during the summer so that the A/C doesn't have to cool air heated by the heater core? I'm trying to find an "elegant" solution that uses the fewest valves possible.
 
His Ford Ranger has an inline valve, factory part. On the Ranger it stays closed until the coolant warms but it could easily be connected to a dash switch..... Rodney would likely wire it to the AC compressor circuit. One valve would do it.
 
billiebob said:
Last April, my heater core was leaking, took it to a shop, they put in a new one. 8 months later it is leaking again, just before the holidays. Last April, I just bypassed the heater core and drove without any heat. Not an option at Christmas. And I definitely need a defroster.

My buddy, jack of all trades, master of none said, we could loop it thru the evaporator.... which I disconnected years ago to get onboard air. It took 1 minute to trade hoses. And works like a damn. Actually since the evaporator is much bigger than the heater core it puts out way more heat. Like biggly more.... and no more leak.

No way to turn the heat off tho. Set the dial to hot, is the coolest setting since air is directed thru the disconnected heater core too. But set the dial to cool, and it pumps out way more heat than ever. Almost feels like you could burn your hand.

Anyone struggling to get enough heat, especially with just a soft top.... in Alaska or the midwest where 40 below is common..... this is a great option.

And the evaporator is built for way more pressure than the heater core.

View attachment 69000
Click to expand...
That is the most redneck thing I've seen in a long time. (Not saying that it is bad). I hope it works out for you until you can get the heater core fixed.

My question is how is the engine temperature. Is it causing any low temperature readings?
 
  • Like
Reactions: billiebob
billiebob said:
His Ford Ranger has an inline valve, factory part. On the Ranger it stays closed until the coolant warms but it could easily be connected to a dash switch..... Rodney would likely wire it to the AC compressor circuit. One valve would do it.
Click to expand...

Great idea. Now the search for the Ranger part begins . . . . What year Ranger does he have?
 
Thanks. Found the valve. It is vacuum operated. There are several write ups of how to plumb it . I'm looking for a manual valve - found a cable operated valve that may work but still looking for one with a lever or wheel. I'm sure there is one out there. Maybe McMaster-Carr.
 
Boinked said:
@Mr. Bills try something like this
Metalwork PEX Brass Full Port Shut Off Ball Valve, 5/8" Barb, 1 Pcs https://www.amazon.com/dp/B07CMC62YR/?tag=wranglerorg-20
Click to expand...

Thanks.

I think what I am looking for is a 4-port valve like this but with a lever or wheel rather than cable operated:

738d8015-5ee8-43d7-b095-806f4a736305.jpg


Open for winter, bypassed for summer or if/when my heater core blows again. I had a hardware store version of this on an old Ford pickup, but it took an "H" manifold and 3 valves like the one you linked. There has to be a better way.
 
Last edited:
  • Like
Reactions: MountaineerTom and Boinked
This is a neat idea. The valve @Boinked posted the link to seems like it would quick and simple to use.

Would you need on both lines to keep any hot coolant from still being in the core?

Would it be ok to have coolant just sitting in the core and not circulating?

I'm interested in this because any extra heat I can get rid of in the cab here in South Carolina during the summer would be nice.
 
Par for the jeepers code! Make it work! My AC leaks via the evaporator, so I'm not looking forward to ripping the dash out.
 
My heater core has developed a leak and I need to get it replaced at some point. I'll keep this in mind. I heard a buddy of mine say that heater cores on the TJ seem to go bad quite a bit, not sure if that was true or not...not even sure why they develop cracks to begin with.
 
Kaynutz said:
My heater core has developed a leak and I need to get it replaced at some point. I'll keep this in mind. I heard a buddy of mine say that heater cores on the TJ seem to go bad quite a bit, not sure if that was true or not...not even sure why they develop cracks to begin with.
Click to expand...


Mine was a factory heater core when it started leaking at 12 years. I can't say that it was THE original core since I'm the 3rd owner, but I'd be willing to bet it was based on everything else on the Jeep. I replaced it with another MOPAR core figuring if I get 12 more years out of it, I'll be happy.

I have heard lots of people have bad luck with parts store heater cores not lasting very long though.

As much as involved with changing the core, I don't want to do it often. Not really hard, just time consuming.
 
MountaineerTom said:
This is a neat idea. The valve @Boinked posted the link to seems like it would quick and simple to use.

Would you need on both lines to keep any hot coolant from still being in the core?

Would it be ok to have coolant just sitting in the core and not circulating?

I'm interested in this because any extra heat I can get rid of in the cab here in South Carolina during the summer would be nice.
Click to expand...

An "H" manifold with a ball valve on the cross and each upper leg (total 3) would allow you to bypass the heater core by stopping flow into and out of the heater core and instead diverting flow through the cross, turning the "H" manifold into a "U". To operate normally the valve in the cross would be closed and the valves in the upper legs would be open. It is an oldtimers "hack" to stop the air conditioner from having to cool air that has been heated by the heater core in vehicles where hot coolant flows through the heater core at all times. I did it in an old Ford pickup and it substantially improved air conditioning performance. I called it a summer/winter valve.

It won't hurt anything to have coolant sit in the heater core for a month or two, and all one needs to do to get fresh coolant into the heater core during "bypass season" is restore flow to normal for a minute or two every once in a while.

The four port valves pictured above are a more sophisticated way to accomplish the same thing. This is what is happening inside:

4_Port_Flow.jpg
 
  • Like
Reactions: Blondie70, StG58, billiebob and 1 other person
That is pretty cool. I'd probably only have the valve open to use heat 4, maybe 5 moths out of the year here in SC.

I wonder if they make a manually activated version of that.
 
Top Bottom
Back