Broken heater core quick disconnects

jatkinson8755 · December 15, 2018

Has anyone else suffered from the stupid plastic heater core outlets breaking or leaking ?

Ive broken 2 of these in the last few years. It seems like dorman or whoever is not making them as well as they used to. 1 of mine is leaking again slightly and I know its a matter of time.

Im trying to get some metal replacements fabricated but I need to know the outlet tube diameter from the heater core. I dont want to mess with mine because I know it will break and I dont have time to work on my truck right now. Does anyone know the heater core outlet tube diameter ? I think its 3/4" but not entirely sure without measuring.

Im talking about this part :

https://www.amazon.com/Dorman-800-409-Heater-Hose-Connector/dp/B000E347PW?tag=silveradosierracon-20

txab · December 15, 2018

Just connect the hoses directly to the heater core tubes with screw clamps. Or try the Gates brand version of the disconnects

Supreme Pizza · December 15, 2018

5 hours ago, jatkinson8755 said:

Has anyone else suffered from the stupid plastic heater core outlets breaking or leaking ?

I have had a fair amount of experience with these connectors - sorry for the long post

I have replaced lots of them on other people vehicles after they complained about water leaks, overheating, or poor heater function. I even broke one on my own vehicle one time. I was changing spark plugs and slipped - my hand hit the heater hose - which broke the connector. At first I was not happy about it. I thought "what a stupid design, why not connect the hose directly to the heater core - or at least make the connector out of metal!". Then I remembered working on older cars. Vehicles in the past did not use any connector at all. They just clamped the hose directly to the heater core, but there were several issues associated with that. Due to the heat and pressure, the hose gets "stuck" on the heater core. When you try to remove it, your twisting and pulling on the hose, which would often damage the heater core solder which resulted in a leak. Now your changing a heater core - which can be extremely difficult and/or expensive. So the only way to prevent this was to cut a slit down the heater hose, and peel it off of the heater core tube. Sometimes the tube had bits of rubber stick to it that were hard to remove. Sometimes the knife would scratch the heater core tube which made it difficult to get a good seal on the new hose. Another problem was that the hose clamp would sometimes crush or deform the heater core tube. Even if everything went well during the removal, your hose gets a few inches shorter every time you cut it off of the heater core.

With the quick connector that GM is using, the heater core is very well protected. No more broken solder on the heater core, no crushed or scratched heater core tubes, no more fighting with stuck hoses, and its actually a lot faster to disconnect the tubes using these connectors. The biggest advantage is that if someone slips and lands on a heater hose (like I did), the connector simply snaps off rather than bending or breaking the heater core. If I had metal heater hose connectors on my rig (or hose clamped), there would have been a very good chance that the heater core would have been damaged. The plastic connector is a great fail - safe, and they are very inexpensive.

If one breaks, just replace them both. Keep a couple extra connectors and the removal tool in your truck's tool box. If yours ever break, or even someone else's - you will be able to save the day in just a few minutes time.

Another way to help protect these plastic connectors, is to secure the heater hoses to inner fender. That will prevent the hose from moving back and fourth as the motor moves under load. It will also help keep the hoses from bouncing around and putting stress on the plastic when you go over speed bumps. Constant movement of the hoses can eventually wear out the O-ring inside the connector, resulting in a leak.

What ever you do, don't break that heater core. They are very brittle.

Edited December 15, 2018 by starman8tdc

jatkinson8755 · December 16, 2018

Ok good replies here guys thanks for all this info. I have several points to add :

1. I don’t think just connecting heater hoses direct to heater core is good idea because it will stretch the hoses and pull on the heater core since hoses aren’t long enough without pulling them towards the heater core connectors. As was mentioned, you don’t want the heater core to break, period. It costs thousands of dollars to replace and at least a week of labor. The heater core itself is weak so pulling the hoses on it is just a bad idea.

2. I get the plastic couplers are meant to be sacrificial but bumping a hose would not break the heater core. The hose would just deflect. Now if you grab the hose and yank the heck out of it then yes you would break the heater core if there wasn’t a sacrificial plastic coupler in place to break first. However, the amount of stress you put on the heater core tubes when replacing the plastic couplers is significant. Constantly changing them out is putting undue stress on that heater core. My plastic couplers were hard to remove, they almost had to be cut off.

3. If you went with a metal coupler and short length of high quality silicone hose, why would you ever mess with it again ? It would permanently fix the issue once and For all. Also, the short length of silicone hose is softer and more pliable than a normal coolant hose, yet much more durable. It would Be connected between metal coupler and the heater core tube, and this would provide an additional level of dampening in case you did bump the heater hose when changing spark plug or such.

I think metal coupler is the best way to go but probably not the least expensive. When you consider the failure rate of the plastic couplers though, high stress changing them can put on the heater core, and just the fact that who the heck wants to be constantly changing these plastic fittings and worrying when they are gonna break next - metal coupler with short bit of silicone hose seems to make the most sense.

please comment and let me know thoughts here

Supreme Pizza · December 16, 2018

When I broke mine, the knees were on the core support, and I had my weight on my left hand, changing spark plugs with the right. My left hand slipped and the hose was the thing that my hand found to stop my sudden decent. I heard a snap, followed by fluid dripping on the floor.

You make a lot of valid points about metal VS plastic.

Your comments have made me question which is the better option.

Each side has its ups and downs.

jatkinson8755 · December 16, 2018

Ive actually seen service techs looking for coolant leaks start grabbing hoses and yerking them !$#% I almost punched a guy out when I saw him do that to my truck. Be very careful disturbing coolant hoses, they are all connected to expensive, brittle parts !

Also this might not have been such an issue years ago, when the plastic couplers actually lasted and were durable. But It just seems like they have done something to weaken the plastic material such that it breaks much easier than it used to. After you buy a few of these plastic couplers, you would probably exceed the price of a proper metal / silicone kit, too. It seems typical GM/Dorman - raise prices and decrease part quality.

jatkinson8755 · December 16, 2018

Heres more discussion about it on Silverado forum :

https://www.silveradosierra.com/engine/heater-core-hose-quick-connect-fitting-failure-t104873.html

swathdiver · December 16, 2018

On 12/15/2018 at 8:37 AM, jatkinson8755 said:

Has anyone else suffered from the stupid plastic heater core outlets breaking or leaking ?

Ive broken 2 of these in the last few years. It seems like dorman or whoever is not making them as well as they used to. 1 of mine is leaking again slightly and I know its a matter of time.

Im trying to get some metal replacements fabricated but I need to know the outlet tube diameter from the heater core. I dont want to mess with mine because I know it will break and I dont have time to work on my truck right now. Does anyone know the heater core outlet tube diameter ? I think its 3/4" but not entirely sure without measuring.

Im talking about this part :

https://www.amazon.com/Dorman-800-409-Heater-Hose-Connector/dp/B000E347PW?tag=silveradosierracon-20