techmitch
Well-Known Member
- May 1, 2008
- 8,456
- Boat Info
- 1999 270 DA
- Engines
- Twin 4.3s W/Alpa I Gen II's
Disconnect the hose that goes to the bottom of your manifold and see how your flow looks. Also check the flow that comes from the raw water pump that goes to the t-stat housing. On a cold engine at 1,000 RPMs you should be getting at least 9 and 1/2 quarts in 15 seconds.
Sure sounds like a blockage to me. I would probably start here also as it's least invasive.