ID of heater return hose at firewall? '89 525?

[Gene in NC]

ID of heater return hose at firewall? '89 525?

Will a 3/4" heater hose fit that firewall/heater connection?

Want to splice in a 3/4" "tee" with screw cap into the hose at the straight point near the firewall. Objective:

1) Schrader valve added to "tee" is set up for attach of bicycle pump with integrated pressure gauge to do cooling system pressure test.

2) Remove "tee" cap, attach garden hose to back flush cooling system.















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[tim eh?]

ID of heater return hose at firewall? '89 525?



return hose is #23 i think (the big one)



http://www.realoem.com/bmw/showparts.do?model=HC23&mospid=47402&btnr=64_0114&hg=64&fg=18

[632 Regal]

i would guess between 5/8 and 3/4 but I pitched old hoses and cant be sure.

[shogun]

I have modified a cap for the expansion tank to be used as connection for a pressure test with a simple pump.
That is easier than such modification. Have a look at the cap.

[Gene in NC]

Completed my little pressure test/flusher splice into heater return line. Works as expected for pressure test. Will report on flush in this engine and add pics when complete. Right now on the way to head gasket job.