Looking for advice on flushing the rear heater core on the 1996 6.5 diesel Suburban

[jrsavoie]

Looking for advice on flushing the rear heater core on the 1996 6.5 diesel Suburban.

I have a black and a green hose going to the T's from the back of the Suburban. Which hose is supply and return?

Or I have a top and bottom T - Which T is the supply and which is return?

There was one line coming off the thermostat housing to one of the T's. Is that the supply?

How much pressure can be used to flush the system? 15lbs? 8 lbs.?

It seems to me that it is Ok to back flush the system as well? Is this correct?

I know there are some old threads on this someplace, but I have not had time to look yet.

 

[THEFERMANATOR]

the line coming from the tstat housing is the supply. i backflush em all the with a garden hose. make sure to flush the rear without the t's in place. most of those t's have restrictors in them and is where they get plugged.

 

[jrsavoie]

Does anybody have the part numbers for what I need to reinstall the line into the thermostat housing?

When I pushed the clips and pulled the line, I got a lot of little rubber pieces. I tried searching some schematics but could not really see what I needed

 

[jrsavoie]

I came up with GM part numbers for the line and the fitting that go to the dual thermostat housing.

I am not sure what is needed for seals. It's been forever and a day since I had this apart.

http://parts.nalleygmc.com/showAssembly.aspx?ukey_product=2814358&ukey_assembly=369992

Line and plastic piece #3 & 4 one part number 15998367

Fitting to the thermostat housing #5 15650056

There was a lot of black rubber that came out of the fitting when we took it apart. I do not know if this was pieces of seal or if it was ultra black from the water pump install.

I am not sure what I need to reinstall things and not have any leaks.

 

[JayTheCPA]

I came up with GM part numbers for the line and the fitting that go to the dual thermostat housing.

I am not sure what is needed for seals. It's been forever and a day since I had this apart.

http://parts.nalleygmc.com/showAssembly.aspx?ukey_product=2814358&ukey_assembly=369992

Line and plastic piece #3 & 4 one part number 15998367

Fitting to the thermostat housing #5 15650056

There was a lot of black rubber that came out of the fitting when we took it apart. I do not know if this was pieces of seal or if it was ultra black from the water pump install.

I am not sure what I need to reinstall things and not have any leaks.

That looks like it will keep the quick-release connector in the system which is also known for leaking.

Here is a post that talks about making the misc parts much more durable: http://www.thetruckstop.us/forum/threads/help-need-t-connector-options.37644/#post-43040

 

[JayTheCPA]

Here is a pic of a nice non-leak-prone NPT. Mechanic switched me over a couple years ago when the quick release started to leak.



The rest of the durable T setup is here: http://www.thetruckstop.us/forum/threads/help-need-t-connector-options.37644/#post-491975

While working on the T connectors, consider adding a valve so that that A/C gets an extra boost during the summer.