986 Forum - The Community for Porsche Boxster & Cayman Owners - View Single Post

gdotcvg · 09-30-2021, 04:06 PM

Water pump - 1998, 2.5L, well maintained. I know I should have replaced proactively. But what is done is done. Time to move forward. My water pump is original and failed without warning at ~50M miles. There was no previous noise, no leakage, it just failed. There is no wobble in the bearing but there is moderate vane damage. Now, how to back flush using best approach and then replace water pump and T-stat. Current state: hoses disconnected and drained, water pump and thermostat removed. Looking for advice on best method to back flush and mitigate debris issue without disassembling the engine. I've searched the forums in detail, but there is a lot of conflicting and incomplete info. I've tried to layout a plan of action below and with expert input/corrections, will hopefully help others in the future.

My current plan
• Ordered Pierburg pump, LN 160 T-stat, gaskets, serpentine belt, oil cooler o-rings, and Porsche coolant.
• Remove oil cooler (known area of possible accumulation) and check for debris then reinstall
• Remove (if possible with engine installed) the “2-bolt” access panel on engine bank-2 transmission side (known area of possible accumulation) and reinstall. Is this possible?
• Please reference photo from Pelican Parts: Isolate and back flush the radiators by adapting hose fitting to “Orange arrow” coolant hose and flow backwards through the radiators and then out the “Green arrow” hose into bucket
• Isolate and back flush the engine by adapting hose fitting to “Green arrow” coolant inlet to engine and then out near the “Orange arrow” coolant outlet. Key questions here are: Do I need to replace the water pump and/or t-stat housing to get effective back flush or keep all open?
• How to back flush the heater core… Do I flow water in the “Red arrow” tube and then out the “Purple arrow” tubing or vise versa?
• Note: water flow will be from a low pressure, high volume centrifugal sump or pool cover type pump and all return water will be captured and filtered.

I’d appreciate any knowledgeable guidance that you can provide. Hopefully JFP will input.

09-30-2021, 04:06 PM	#1
gdotcvg Registered User Join Date: Sep 2015 Location: SW Ohio Posts: 28	Water Pump and back flush questions Water pump - 1998, 2.5L, well maintained. I know I should have replaced proactively. But what is done is done. Time to move forward. My water pump is original and failed without warning at ~50M miles. There was no previous noise, no leakage, it just failed. There is no wobble in the bearing but there is moderate vane damage. Now, how to back flush using best approach and then replace water pump and T-stat. Current state: hoses disconnected and drained, water pump and thermostat removed. Looking for advice on best method to back flush and mitigate debris issue without disassembling the engine. I've searched the forums in detail, but there is a lot of conflicting and incomplete info. I've tried to layout a plan of action below and with expert input/corrections, will hopefully help others in the future. My current plan • Ordered Pierburg pump, LN 160 T-stat, gaskets, serpentine belt, oil cooler o-rings, and Porsche coolant. • Remove oil cooler (known area of possible accumulation) and check for debris then reinstall • Remove (if possible with engine installed) the “2-bolt” access panel on engine bank-2 transmission side (known area of possible accumulation) and reinstall. Is this possible? • Please reference photo from Pelican Parts: Isolate and back flush the radiators by adapting hose fitting to “Orange arrow” coolant hose and flow backwards through the radiators and then out the “Green arrow” hose into bucket • Isolate and back flush the engine by adapting hose fitting to “Green arrow” coolant inlet to engine and then out near the “Orange arrow” coolant outlet. Key questions here are: Do I need to replace the water pump and/or t-stat housing to get effective back flush or keep all open? • How to back flush the heater core… Do I flow water in the “Red arrow” tube and then out the “Purple arrow” tubing or vise versa? • Note: water flow will be from a low pressure, high volume centrifugal sump or pool cover type pump and all return water will be captured and filtered. I’d appreciate any knowledgeable guidance that you can provide. Hopefully JFP will input.