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.