HELP!!! Coolant Leak On Back Of Motor On 97 5.7L - Chevrolet Forum - Chevy Enthusiasts Forums
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HELP!!! Coolant Leak On Back Of Motor On 97 5.7L

tcr1016's Avatar
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Join Date: Oct 2010
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October 15th, 2011, 10:35 AM   #1  
HELP!!! Coolant Leak On Back Of Motor On 97 5.7L

<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:PunctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <wontGrowAutofit/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><!--[if gte mso 9]><xml> <w:LatentStyles DefLockedState="false" LatentStyleCount="156"> </w:LatentStyles> </xml><![endif]--><!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} </style> <![endif]--> I have a coolant leak on my 1997 GMC Savana 5.7L on the back of the engine. It seems to leak only a couple hours after sitting, say overnight. It hesitates when I hit the gas after it sits. It also has a bit of a popping sound in the exhaust. I got a Check Engine Light that the trouble codes were PO171 and PO174.

I changed the thermostat thinking that is what leaked, but it wasn’t. I replaced the fuel filter and it still hesitates. Is it the lower intake manifold and would that leak coolant?? Also has anyone changed the intake gasket themselves??

I have done a video showing everything in detail: 97 GMC Savana Coolant Leak on 5.7L - YouTube

If you have any questions or need clarification, do not hesitate to ask.

Thank you for any help.

kevinkpk's Avatar
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October 15th, 2011, 2:48 PM   #2  
Those codes are O2 sensor upstream, both sides. Is there any white smoke? Also I cannot tell from the video if it is the intake or head gaskets. Zoom in better so I can see. The head gasket would cause an O2 sensor to give false readings, and both sides leaking if it is a head gasket would explain that. Has the engine ever overheated? What has changed?

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