[JJsays77]

I have a leak in the heater core somewhere. It leaks whenever I fill the coolant back up. Is coolant supposed to be flowing though the heater normally?
Also, because I live in Arizona, can I just plug it off or something?
It’s quite frustrating too because I actually invested the time to replace the old one (it was leaking too, super rusted etc) and in less than two years this one leaks.


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[98whitelightnin]

coolant flows through the heater core when the truck is running. You can disconnect the hoses at the core and loop them back together to bypass the heater core

 

[Pavement Tested]

coolant flows through the heater core when the truck is running. You can disconnect the hoses at the core and loop them back together to bypass the heater core

And not have heat...

 

[BFD]

We have a week of low 100s coming up but hopefully it will cool off some day!

 

[Pavement Tested]

We have a week of low 100s coming up but hopefully it will cool off some day!

I missed the info on where the OP is from, but I need heat in the morning these days to defog the windows if for nothing else.

 

[98whitelightnin]

He is from Arizona, must not be northern part since he acted as if heat was not needed there

 

[Pavement Tested]

He is from Arizona, must not be northern part since he acted as if heat was not needed there

That's what I get for not reading all the words... Doesn't it get cold in AZ some of the year too?

 

[NIsaacs]

That's what I get for not reading all the words... Doesn't it get cold in AZ some of the year too?

It does where I live, Snowflake. I have seen minus 17 several times. Normal is about 0 for the coldest.

 

[98whitelightnin]

The coldest I’ve ever been was standing over the south rim of the Grand Canyon

 

[NIsaacs]

coolant flows through the heater core when the truck is running. You can disconnect the hoses at the core and loop them back together to bypass the heater core

OP, be sure and loop them together like 98 said. If you block them off you loose the bypass effect and the water pump pressure at high RPM's can blow out the head gasket at the coolant ports. I see you have a highly modified truck, so I assume high RPM is normal. High RPM can also blow out the heater core. Again, the water pump can flow more than the heater core can take. You might need to use a restrictor at the head port that feeds the heater. I think it is a 1/2" pipe nipple and might even be slightly restricted. I recommend about a 5/16" restriction on a hi output Cummins to protect the heater core.

 

[BFD]

The oem HWS nipple is already restricted to protect the core from the pressure. I plugged the heater water on my 03 for several summers til I could fix the dampers and no blown gasket. Engines have a bypass cast in to keep from dead-heading the pump. Old cars had shut-off valves and I never had to replace a head gasket in them.
So, what rpm is dangerous?

 

[NIsaacs]

The oem HWS nipple is already restricted to protect the core from the pressure. I plugged the heater water on my 03 for several summers til I could fix the dampers and no blown gasket. Engines have a bypass cast in to keep from dead-heading the pump. Old cars had shut-off valves and I never had to replace a head gasket in them.
So, what rpm is dangerous?

Yes, the oem heater hose nipple is restricted, but with older trucks and several owners, who knows....The Cummins is a medium duty engine and designed for 2600 rpm. When you push 3k you are pushing your luck. The oem bypass port at the thermostat, is right on the edge of the block/head with a super thin bead of silicone. This location is on the right front corner, over time they can and will leak there.

I have seen nice new silicone heater hose bulge when the engine is revved up. Sled pullers that run real high rpm install bypass systems to prevent soft plugs from blowing out. I blew several heater cores in my '75 F-250 with a high performance 428 before I figured out what was happening. When I used a restrictor all was golden.

It is not just any engine or head gasket, it is the Cummins. Picture of what I am talking about, at the 3 blue dots.

 

[LD-Ordie]

I live on the outskirts of Death Valley, super hot in the summer, but still gets in the 20's and 30's in the winter. Heater core is also leaking........but will be changing it out ASAP

 

[BFD]

3/8” ID is very common for heater water nipples. I’ve known about the restricted nipples and pump bypasses since auto shop in the 60s and I saw it when I had shops in the early 70s and changed hoses and water pumps.
My 5.9’s were also 3/8” ID.
I deleted the Rube Goldberg EGR delete that the PO put on my 12 and I capped the standpipe. I saw that the heater nipple was 1/4” ID to work along with the EGR coolant flow. I had read about the water jacket pressure problems and blowing out the rear block plug so I used a pressure gauge and thermal couples to check P&T at the front and rear of the head to see what was going on after what I changed. I saw up to 63 psi and there was no difference in pressure or temperature between the front and rear and I was running it up to 3500 RPM regularly, towing and empty, so I could see if there was any temperature problems. I thought I would see some PSI pattern but there was no rhyme or reason to the pressure and it didn’t matter if the thermostat was just beginning to open or if it was fully open and RPM didn’t matter either… 63 psi was the max.
So I drilled the heater nipple to 3/8”, like the 5.9s, and max psi went down to 53. I used the two tapped holes that are on either side of the rear block plug and tabbed it and then I was satisfied with everything.
my 97 215 with 3K kit also pulled hard to 3500 RPM and I needed that rpm regularly with the five speed, 3.54 and towing in the mountains.
I made sure all of my Dodge CTD’s had enough turbo and fuel to pull that high and I was never afraid do use it.
I believe you’ve seen the blown gaskets in that bypass area but I wonder how much of it has to do with higher power levels and too much timing, just like the blown head gasket problems that so many guys have with rotten tuning. I’ve always been very careful with my tuning and don’t allow timing rattle.
Interesting subject, for sure!

 

[Yukonjackman1]

I have a leak in the heater core somewhere. It leaks whenever I fill the coolant back up. Is coolant supposed to be flowing though the heater normally?
Also, because I live in Arizona, can I just plug it off or something?
It’s quite frustrating too because I actually invested the time to replace the old one (it was leaking too, super rusted etc) and in less than two years this one leaks.


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I also live in Arizona I have a valve in the heater hose to shut off the water so my ac works better, get a pressure test on the radiator look where the water is coming out of

 

[bigfish95971]

Should not need a valve, you blend door takes care of that for max or hi cool air. No air goes through heater core for cold air.

 

[Yukonjackman1]

I have a leak in the heater core somewhere. It leaks whenever I fill the coolant back up. Is coolant supposed to be flowing though the heater normally?
Also, because I live in Arizona, can I just plug it off or something?
It’s quite frustrating too because I actually invested the time to replace the old one (it was leaking too, super rusted etc) and in less than two years this one leaks.


Enviado desde mi iPhone utilizando Tapatalk

I'm in the valley 2001dodge diesel, I have a valve installed off in warm weather open in cold weather