AC Delco 15-33220 Replacement

[Whiskey Junior]

So my 1989 has the quick connect fitting that mates to the intake manifold and dumps hot coolant to the Heater Core. That fitting is known by all to be of a weak composition, and prone to failure.

I have to replace my Evaporator Box soon, and while I have all of that AC hardware loose from the firewall, I will be replacing the heater core. While this operation is happening, I am trying to prepare for a possible catastropic bend or break of that original heater hose and connector kluge that came directly from GM.

I don't want to find some NOS fitting to replace the old one with a similar type, but I am having problems locating the replacement part. GM had produced an adapter, PN 15-33220, that had both the 3/4 hose fitting and the 1/2 NPT intake fitting, but the 15-33220 has a restriction in the pipe to reduce the flow through the heater core in order to prevent premature failure/rupture of the core.

I figure I am stuck with modifying a standard 3/4 barbed fitting to 1/2 NPT, and fabricating a restriction to put in the adapter, but I'd like to have the part in hand before I start the job, so I havent any good way to measure the restriction orifice before starting the project. Do any of you folks here happen to know what the reduction diameter may be in that 15-33220 part?

I have included a picture of the part for reference, but I can't seem to find it anywhere online. Jegs thinks they have it, but their parts expert was unable to locate in the warehouse.

Thanks!!!!

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[fast 99]

Original fittings are some sort of pot metal, aftermarket replacements are steel.

 

[Whiskey Junior]

Absolutely, Brian. I can't seem to locate the GM part, nor find an aftermarket part that has the reducer built in. Any idea what the orifice size in the GM part may be? I will know for certain (I hope) when I pull the old one off (break the old one off?), but I was hoping someone would know it sooner.

 

[Whiskey Junior]

The GMT400 forum describes 3/8 orifice. Let me see what my machinist can make for me.

Similar post on GMT 400 Forum

 

[fast 99]

try Dorman 800-401 although none of listings showed the interior, they may have a restrictor.

 

[Turbo4whl]

I know the GMT400s have those poor hose connections but why do you want the 3/4" hose? The previous year squares feed the bottom inlet of the heater with a 5/8" hose with coolant from the manifold. Return from the upper heater core connection is a 3/4" hose and returns to the water pump or radiator.

Is the heater core different in the carry over year Suburbans?

 

[Whiskey Junior]

I'll crack open the hood and double check; I'm not sure but 3/4 does sound a bit wide.

 

[fast 99]

If it is put back the way GM designed it, the heater it will work. Guess I don't really understand what you're trying to accomplish. I have never had to install a stand-alone or redundant restrictor.

 

[Whiskey Junior]

Brian,
I can't find the original GM part, which features the restriction. I don't really want to go back to the old quick-disconnect interface, and the only other parts I have found don't appear to have the restriction. I am nervous to feed full flow speed from the engine hot-water source through the heater core, as I know that can cause some heater cores to rupture. I will get the machine shop to turn down a small plug of brass to fit into the heater core inlet pipe featuring the correct orifice, which will reduce line flow.

 

[Rustisbest]

It can happen. My heater core started to leak after a few high RPM blasts with the new engine. I just put a stainless all thread coupling nut in the inlet hose, with a clamp on the outside. Dont remember the size but it was a snug fit.
Haven't had any recurring issues after replacing the heater core.

 

[TFerguson]

I did the same thing when replacing the heater core on my '90 Blazer a couple months back. I used ACDelco 155372, from Rock Auto: https://www.rockauto.com/en/moreinfo.php?pk=84489&cc=1061558&pt=6860&jsn=8

 

[Whiskey Junior]

I just bought that adapter, I will post my results when I install. Thanks for the help!