Coolant Quick Disconnect

[Oldswagon]

The coolant quick disconnect on the rear of the intake for my Chevy 350 began to leak a bit. So I decided to change it when I did my rad. I HATE coolant quick disconnects, and the factory aluminum hose was starting to show some corrosion damage (original part). This hose runs from the back of the engine to supply the heater cores (there are two on my truck).

So I made up my own fitting from brass hardware. The original part is 1/2" NPT, so I used a brass fitting with that threat and a nipple on the end where I used a worm gear hose clamp on a regular heater hose. The other end of the factory hose was already a rubber end with a hose clamp.

My only concern is the original connector had a restrictor inside, which appears to restrict the coolant flow. My new part doesn't have this restriction. Does anyone know why GM put a restriction in there? Will the higher flow cause any problems?

After I installed new part, I discovered that I can get a threaded nipple from GM that has the same restrictor in place. Do you think it’s worth the effort to change the fitting to the GM fitting?

 

[KilgoreBass]

Great timing, I have a 92 4.3 S-10 that's showing a bit of white powder on my heater hose to engine connector. It also appears to be the "quick connect" type. There's not any noticeable coolant level drop, but it has me concerned with summer coming. The collet on the fitting is falling apart, and there is white powder present, so I don't even want to touch it until I have a plan. It looks like it will break if I test for tightness.

I'm assuming it's very similar to your problem, so please keep us informed.

Oh, thanks for the heads up on the restrictor (or is it a check valve?). I was also considering using a standard off-the-self fittings, but wasn't exactly sure of the size.

I sure love vehicles with the mishmash of SAE and Metric parts.....

 

[Chris142]

Yes you need the restricter! It prevents cavitation damage to the heater core. When I do what you did I shove a small piece of pipe into the heater hose with a piece of metal soldered to the pipe and that piece of metal has a 3/16 hole drilled in it.

 

[Oldswagon]

Originally Posted By: Chris142
Yes you need the restricter! It prevents cavitation damage to the heater core. When I do what you did I shove a small piece of pipe into the heater hose with a piece of metal soldered to the pipe and that piece of metal has a 3/16 hole drilled in it.


How soon should I fix this? What type of pipe do you use? I should be able to rig something up on the weekend, but I need the truck for the next few days and don't have time to fix it.

Also, will the brass fitting in the aluminum cause a problem? To be honest, I needed to get the truck back on the road, this was my best solution after the new quick connect leaked as well.

 

[Oldswagon]

Originally Posted By: KilgoreBass
The collet on the fitting is falling apart, and there is white powder present, so I don't even want to touch it until I have a plan. It looks like it will break if I test for tightness.

I'm assuming it's very similar to your problem, so please keep us informed.

Oh, thanks for the heads up on the restrictor (or is it a check valve?). I was also considering using a standard off-the-self fittings, but wasn't exactly sure of the size.



I got lucky and mine didn't break when I removed it, but I soaked it in PB blaster which probably helped. Most people seem to break them when they try to take it out.

It's definitely a restrictor, and from what Chris is saying it's obviously important.

 

[KilgoreBass]

Originally Posted By: Chris142
Yes you need the restricter! It prevents cavitation damage to the heater core. When I do what you did I shove a small piece of pipe into the heater hose with a piece of metal soldered to the pipe and that piece of metal has a 3/16 hole drilled in it.


Thanks for the info. I'll probably be better off getting an OEM type part if that's the case. Does anyone know what this is called by GM, or a part #, etc? 4.3L should use the same part as a 350, right?

PS: It sounds like the OP will be OK as long as he doesn't use the heat.

 

[Chris142]

Originally Posted By: Oldswagon
Originally Posted By: Chris142
Yes you need the restricter! It prevents cavitation damage to the heater core. When I do what you did I shove a small piece of pipe into the heater hose with a piece of metal soldered to the pipe and that piece of metal has a 3/16 hole drilled in it.


How soon should I fix this? What type of pipe do you use? I should be able to rig something up on the weekend, but I need the truck for the next few days and don't have time to fix it.

Also, will the brass fitting in the aluminum cause a problem? To be honest, I needed to get the truck back on the road, this was my best solution after the new quick connect leaked as well.
The piece of pipe I use I cut off from old heater cores we have laying around. 5/8 or 3/4 depending on the size of the hose. I just solder the end, drill a hole in the end and stuff it in the hose.

I don't think that running a few days w/o the restricter will matter. Just don't forget about it.

Nothing wrong with the brass and aluminum.

 

[Chris142]

Originally Posted By: KilgoreBass


PS: It sounds like the OP will be OK as long as he doesn't use the heat.
Doesn't matter. There is no heater valve on the truck so water is flowing through the heater even when the heat is off.

 

[KilgoreBass]

OK, guess I'm still in the old school mind set, where coolant only circulates the core when the heat control slider is moved.

I found the needed part, and it looks like it's specific for model and year, etc. It's probably cheaper than making something after all the time needed. I'm also ordering a new heater hose, as I'm not sure what condition it will be inside the nipple.

Thanks for all the info. I *think* these are the right parts

Rock Auto

ACDELCO 1575224 (15-75224) Heater Inlet Nipple $ 8.51 $ 0.00 1 $ 8.51

DORMAN 626103 (626-103) Heater Hose Assembly $ 18.23 $ 0.00 1 $ 18.23

 

[Oldswagon]

My BIL took a standard brass fitting with 1/2" NPT threads on one end and a 3/4" barb on the other end. He then soldered a solid cap and drilled out the hole for the restriction. Works great so far, and it was an easy install with a 7/8" deep socket. This setup is SO much better than the factory quick connect and hard aluminum line.

Here are some pics for those interested in replacing a quick connect on a GM truck intake: