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OEM Water pump question

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Old Apr 5, 2003 | 08:28 AM
  #1  
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Default OEM Water pump question

Which is the inlet and outlet? There is a bigger diameter tube and a smaller diameter tube. Which one is which?

I looked in my service manual but it doesn't say which one is which.

I have an after market heater and I want to hook the lines up to the OEM aluminum tubes. I don't have my water pump on hand so I can't check to see if it is marked on the pump. <img border="0" title="" alt="[Frown]" src="gr_sad.gif" />

TIA

Tom
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Old Apr 5, 2003 | 04:22 PM
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Default Re: OEM Water pump question

ttt
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Old Apr 6, 2003 | 08:27 AM
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Default Re: OEM Water pump question

ttt <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
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Old Apr 8, 2003 | 06:47 AM
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Default Re: OEM Water pump question

Anyone know? <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
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Old Apr 8, 2003 | 03:20 PM
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Default Re: OEM Water pump question

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Fenris Ulf:
<strong> </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Tom the roofer:
<strong> Thanks for the info but I am talking about the 2 5/8" + - hoses that come out of the side of the pump and go to the heater core. Which one feeds the heater core and which is the return line from the heater core? 1 is larger than the other.

TIA
Tom </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I would think the smaller diameter tube would be the return line to account for the pressure drop across the heater core, but don't quote me <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Well, I broke down and called my local Chevy dealer. They looked in all the manuals and concurred the manuals do not give that information. They had a mechanic pow wow while I was on hold and they concurred the bigger line was the output and the smaller line was the return.

I'm going with that info.

Thanks

Tom
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Old Apr 9, 2003 | 12:15 AM
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Default Re: OEM Water pump question

The outlet is the one coming from the T-stat housing going to the lower radiator hose. The inlet is hose is the one on the pump itself up on top.
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Old Apr 9, 2003 | 12:49 AM
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Default Re: OEM Water pump question

Thanks for the info but I am talking about the 2 5/8" + - hoses that come out of the side of the pump and go to the heater core. Which one feeds the heater core and which is the return line from the heater core? 1 is larger than the other.

TIA
Tom
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Old Apr 9, 2003 | 12:57 AM
  #8  
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Default Re: OEM Water pump question

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Tom the roofer:
<strong> Thanks for the info but I am talking about the 2 5/8" + - hoses that come out of the side of the pump and go to the heater core. Which one feeds the heater core and which is the return line from the heater core? 1 is larger than the other.

TIA
Tom </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I would think the smaller diameter tube would be the return line to account for the pressure drop across the heater core, but don't quote me <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
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Old Apr 9, 2003 | 01:46 AM
  #9  
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Default Re: OEM Water pump question

That's what I figured. The import crowd sometimes downsizes the exit piping from the intercooler for the same reason.
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Old Apr 10, 2003 | 09:24 PM
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Default Re: OEM Water pump question

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by CMNTMXR57:
<strong> The outlet is the one coming from the T-stat housing going to the lower radiator hose. The inlet is hose is the one on the pump itself up on top. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I'm not being a smart *** or anything, but you have it backwards. The inlet is where the thermostat housing is and the out let is above the water pump pully. That's why the T-stat is in the housing backwards.

Frank
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Old Apr 11, 2003 | 07:02 AM
  #11  
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Default Re: OEM Water pump question

Look, between this section and the hybrid section, everyone has got this wrong. The 3/4" heater line on the water pump is the return from the heater core. The 5/8" is the outlet from the pump to the heater control valve and then to the heater core inlet. This is the pressure line. This is how you properly account for head loss across the core. Even if you hook it up backwards, the only bad thing that can happen is that you will introduce radiator cooled water to the heater core first and so heat will not be as hot...initially.
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