Help on heater output and inlet
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Teching In
Joined: Oct 2002
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From: Austin, Texas
Help on heater output and inlet I am finishing up the install of a 2000 Corvette crate motor in my 63 split window Corvette and need someone to advise me on which of the two outlets on the water pump is output and which is inlet. One is 3/4 inch and the other is 5/8 inch. Thanks
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From: NH
Re: Help on heater output and inlet 70 LS1 wrote:
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">"The larger is output and the smaller is return."
</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Are you sure? Conventional wisdom would agree with this. But, I have the LS1 Engine Kit Installation guide sold by GM with their crate LS1 motor and there they describe the following:
"Connect a 5/8" hose to the rear outlet on the water pump and a 3/4" return hose to the front inlet."
So, what is it. I am plumbing my Vintage air system right now and need to make sure I install the heater valve in the proper direction. Any clarification would be welcome.
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">"The larger is output and the smaller is return."
</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Are you sure? Conventional wisdom would agree with this. But, I have the LS1 Engine Kit Installation guide sold by GM with their crate LS1 motor and there they describe the following:
"Connect a 5/8" hose to the rear outlet on the water pump and a 3/4" return hose to the front inlet."
So, what is it. I am plumbing my Vintage air system right now and need to make sure I install the heater valve in the proper direction. Any clarification would be welcome.
Re: Help on heater output and inlet I don't think this is rocket science! I just matched my 3/4" hose to the 3/4" outlet and the same with the 5/8". Heater has worked fine for 1-1/2 years!
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From: NH
Re: Help on heater output and inlet John are you a little testy today?
<img border="0" title="" alt="[Frown]" src="gr_sad.gif" />
Rocket science.....hardly. But, my vintage air coil has two 5/8" connections not one of each. Also, the heater servo valve MUST be connected in the proper direction or else the AC will blow hot air. I like to hook it up once correctly and be done.
<img border="0" title="" alt="[Frown]" src="gr_sad.gif" />
Rocket science.....hardly. But, my vintage air coil has two 5/8" connections not one of each. Also, the heater servo valve MUST be connected in the proper direction or else the AC will blow hot air. I like to hook it up once correctly and be done.
Teching In
Joined: May 2003
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From: Ramona, Ca
Re: Help on heater output and inlet I am bumping this to the top to ask if 67Camaro and 63Split Window hooked up their heaters and got them working. If so did you use the 3/4 as feed and 5/8 as return??
Thanks,
Nick
Thanks,
Nick
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From: Woodstock, IL.
Re: Help on heater output and inlet I am glad you bumped this one..... My reply was made when I thought the thermostat was the outlet. I rarely post unless I am sure of something and I was sure at the time 
knowing now that the thermostat is the inlet ......It would make the small one the feed and the big one the return. Sorry for any confusion I may have caused
knowing now that the thermostat is the inlet ......It would make the small one the feed and the big one the return. Sorry for any confusion I may have caused LS1 Tech Stories
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Joined: May 2003
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From: Ramona, Ca
Re: Help on heater output and inlet LS1swap,
I hooked mine up that way (small is supply) and the heater seems to work fine. I haven't charged the a/c yet but don't think it's related. If I remember right if you put your finger in the small opening it could come out the large opening (if it was long enuf). Not sure it makes a difference.
I hooked mine up that way (small is supply) and the heater seems to work fine. I haven't charged the a/c yet but don't think it's related. If I remember right if you put your finger in the small opening it could come out the large opening (if it was long enuf). Not sure it makes a difference.
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From: NH
Re: Help on heater output and inlet Yes, the 5/8" line is the pressure line (outlet) and the 3/4" is the return. I hooked the 5/8" to my heater control valve on my Vintage Air system and it works great!
