Gm Truck Heater Core Quick Connects

[George7941]

Truck suddenly sprung a leak at the heater core inlet quick connector, the one on the right hand side. I plan on changing both hoses and the two quick connectors.
RockAuto has both the plastic quick connects and aluminium ones. The aluminium ones are listed as OE FIX but are double the price. Should I get the aluminium ones or stay with the plastic ones?

 

[Chris142]

I always just removed them then shoved the heater hoses past that retaining bump and put hose clamps on them.

I never could get the new fittings to seal and always had a drip there.

 

[George7941]

Thanks, Chris. I think I will do just that.

 

[GMBoy]

This is one of those not if but when they will leak or burst. The plastic gets brittle over time and just falls apart. Very bad thing to happen on the road if goes on you. I have usually used replacement plastic ones but have been eyeing up the metal ones because it does seem like a final fix vs plastic.

 

[Snagglefoot]

How many years on the first ones and how many more years do you plan to keep it?

 

[George7941]

These are the originals, 15 years of age, and I plan on keeping the truck for another 5

 

[Snagglefoot]

These are the originals, 15 years of age, and I plan on keeping the truck for another 5

It sounds like plastic will do the job but if the cash is not much go with aluminum.

 

[Kira]

Roll the dice and pray some plastics fabrication company bought the "better (heat resistant) pellets" for this contract?
TRANSLATION: You likely won't get the same quality as the 15 year old originals
What do they cost in plastic? You say peace of mind costs double.

Just learning that a pal's Dodge Grand Caravan has plastic T's (or Y's) in its heating system. Metal replacements are available here too.
Good luck with your decision and if you do go plastic don't let the specter of failure on the highway resulting in breakdown, lost time and possibly a destroyed engine interfere with a good night's sleep.

 

[JMJNet]

I am not really sure how this one is constructed but GM have a few of these in my diesel suburban coolant lines.

It has a plastic tee and quick connect that is metal but the clamp is plastic.
In both cases, I can get a metal replacement.
The quick connect was replaced with brass NPT to barb connector.
The plastic tee was replaced with brass tee from HD.

 

[Duffyjr]

These are the originals, 15 years of age, and I plan on keeping the truck for another 5

Do the new owner a favor and get the aluminum, unless you follow Chris142's advice.

 

[George7941]

I am not really sure how this one is constructed but GM have a few of these in my diesel suburban coolant lines.

It has a plastic tee and quick connect that is metal but the clamp is plastic.
In both cases, I can get a metal replacement.
The quick connect was replaced with brass NPT to barb connector.
The plastic tee was replaced with brass tee from HD.

Your Suburban setup seems to be different from mine, no NPT anywhere on the Sierra heater hoses. For now I am going to bypass the heater core by tying the inlet and outlet hoses together with a barb coupler. I need the truck for work and won't have time to work on it till the weekend.

I am leaning towards Chris's suggestion of clamping the hoses directly on to the heater core pipes and eliminating the quick couplers altogether.

 

[Snagglefoot]

Roll the dice and pray some plastics fabrication company bought the "better (heat resistant) pellets" for this contract?
TRANSLATION: You likely won't get the same quality as the 15 year old originals
What do they cost in plastic? You say peace of mind costs double.

Just learning that a pal's Dodge Grand Caravan has plastic T's (or Y's) in its heating system. Metal replacements are available here too.
Good luck with your decision and if you do go plastic don't let the specter of failure on the highway resulting in breakdown, lost time and possibly a destroyed engine interfere with a good night's sleep.

Plus making a new group of friends at a rest stop. Whatever scares a person.

 

[George7941]

I bypassed the heater core for now so that I can keep using the truck till I have time to work on it. The coolant filter you see is one I added on after I got the truck. The inline valve you see is closed in the photo but I did open it later.

 

[mk378]

On most GM the heater circuit also serves as the bypass hose that lets coolant circulate and equalize the temperature through the engine before the thermostat opens. So it's important not to block it.

 

[George7941]

Yes, the flow through the heater core serves as the bypass flow. In the nineties GM had an issue with high flow through the heater core causing cavitation erosion and consequent failure of the core and they had to put in flow restrictors to reduce flow through the core.

The valve with the red handle you can see in the photos is used to restrict the flow through the core. I reduce the flow a bit, to about 80% of full flow, for 9 months out of the year. I keep full flow only during winter months.