Chevetter Heater Core. Which barb is in and which is out?

Newbie question.. I googled for the answer and couldnt find it. I have an 86 or 87 Chevette heater core for the H2O system I am building. The left barb is larger - without measuring it looks like it's about 3/4". The right barb is smaller - looks about 5/8". Does it matter which one has the water flowing in and which one has the water flowing out?


I will be using 3/8" ID tubing, swiftech 5000a and mcw50 w/ a 296gph Quiet One pump. I want to set it up like this but I don't know which barb is in and which is out....

heater core > cpu > gpu > pump

I don't know which is in or which is out...but from my limited experience it shouldn't really matter. Unless you are mounting the HC on the top of the case then it should (at least to me) be bottom to up. Meaning the inlet is the bottom and the discharge is the top...I would suspect you would want to this to get rid of air bubbles effectively.

Yup, mount it in whichever way is most convenient. It matters not.

Normally, the 2 tubes coming out of the heatercore are 5/8 inch then one is expanded up to 3/4 inch; a few are 3/4 all the way into the heatercore tank.

On mine, I cut both tubes leaving about an inch of the tubing from the tank; at that length both were 5/8 inch diameter. If you cut the tubes, be careful of metal shavings inside the core. I stuffed most of a plastic bag into each tube before cutting the tube (and bag); that seemed to keep shavings out of the core but I thoroughly flushed it with water just to be safe. Remove the bag(s) after cutting

For 3/8 ID tubing, you may want to epoxy or solder barbs into cut-back tubes. 1/2 ID clearflex will strech over the 5/8 tubes but it sometimes has to be warmed in hot water first.

This should answer your question
http://www.ocforums.com/showthread.php?s=&threadid=223521
Eddie

Thanks guys for all the replies. This is the one that I bought from NAPA

http://www.napaonline.com/cgi-bin/n...r=15557101&prmenbr=5806&usrcommgrpid=78756155

According to this link:

Attributes:
Attributes: Heater Core
Length: 6 1/8''
Width: 2''
Height: 6''
Hose Size: I 3/4'' O 5/8''
Type of Packaging: Boxed


It appears that the larger barb is the inlet. Not sure if it really matters but I am gonna go with using the larger barb as the inlet like NAPA says. I JBWelded some plastic 3/8" ID barbs onto the core's existing tunes.