413 heater hose connections - which is to and which from the heater?

[JCMAC]

  Like a dummy, I forgot to take a pic of the heater hoses as they are attached to the water pump housing.  There are two (2) 3/8" parallel pipe nipples angled upwards at about 45° - one more towards the C/L of the coach by about 2".
  Now which is water to the heater box and which is the return?

Thanks,
John
'72 D22C (under-going refurbishment)

[Stripe]

Ok, did a lot of googling and reading and from what I have seen, the output from the 413 water pump housing to the input of your heater core is the one that is laying parallel to your engine towards the rear of your rig.  I have attached two photos one of an industrial 413 pump and housing still on the motor and one of mine (440-3). 
If your water pump is like mine, the output from the housing to the input of the heater core as your looking at the housing from in the rig is going to be the connector closest to the passenger side of the Rig (again see pic of MY WP and Housing).
Failing that, another way to figure this puzzle out (and no snickering from the rest of you) is to look at the hoses, they stiffen over time ( I said no snickering) and hold the shape they were in while attached to the water pump. if the two connections on the water pump are at different angles then it should be easy to figure out. Just hold the hose ends close to the connectors and see if they line up right.

NOW another method, one I used YEARS ago when there was no such thing as the "internet" and I was too clueless to ask a mechanic, was to take two lengths of garden hose about 6' in length and hose clamp them to the connectors on the pump housing and put the other ends into a 5 gallon paint bucket with about 6" of 50/50 coolant/water mix.  I started the engine turned my heater on, set temp to max and just waited. After noticing the mix in the bucket was moving, I pulled one of the hose ends out and got lucky it was the output from the pump to the heater core.  I put the hose back into the bucket and I could still tell which was which (in retrospect I could have dropped a couple of drops of food dye into the bucket and watched).
After that, it was a cakewalk.  BTW, I so totally miss that Olds Delta 88... Had to replace the heater core because of a leak. I was dumb enough to have taken the hoses off the WP and HC.. (dun ask).

Anyway, I hope this helps!

CMM500

[JCMAC]

  Thanks for the info and pics    However, my outlets are both on the RH side of the water pump outlet.  Looking more closely, the pipe closest to the main 2" water outlet to the radiator is the pressure/outlet side as one of your pics show. 
  I notice two other 5/8"± fittings on the LH side of the 2" outlet in your pic, which I do not have Hm?
  In any case, it probably does not make a big difference as the hot water flow is shut off when not needed - tho hot non-flowing water would conduct some heat.
Thanks,
John

[Wantawinnie]

Here is the setup on my 1973 413 Winnebago. It has both outlets on the passenger side of the pump. On mine the upper water pump port connects with the lower port on the heater core and the lower water pump port connects with the upper port on the heater core.






Hope this helps.

[Stripe]

Fantastic!  And thanks for the info.  Those pics are pretty darn sharp too.

CMM500