Overheating under 2000 RPM

[michaeld_5025]

I have an 1989 Scarab 350 Alpha 1 that keeps overheating at low rpm and cools fine at higher rpm. Any suggestions on what could be causing this issue.

 

[nola mike]

I have an 1989 Scarab 350 Alpha 1 that keeps overheating at low rpm and cools fine at higher rpm. Any suggestions on what could be causing this issue.

Default answer is drive impeller. When was it last changed?

 

[michaeld_5025]

Changed two months ago. The old one was in one piece, but the fins were curled and did not straighten out. Changed the housing as well. Have checked to make sure I’m getting water flow to the power steering cooler and no blockage. Not sure how much water flow should be, but getting water flow. At 2000 rpm the water flow is more so the impeller seems to be functioning ok. Thermostat is operating fine.

 

[michaeld_5025]

Should this be letting water by? This is a pick off the internet but mine is the same and seals when not running and springs seem to be ok. When running some water is passing by. No trash but some rust.