You said you changed the impeller and a new raw water pump. I think what you're saying is that you did two things to the raw water pump, but I'm not sure you're not talking about both the raw water pump and the engine coolant pump. Assuming you did nothing to the coolant (fresh) water side of the system, It sounds to me you're not getting good flow in the coolant side of the system at idle. Could be lots of reasons, including low coolant level, a restriction in the system (air bubbles or scale), weak coolant pump and others I'm not immediately thinking of. I had a similar problem related to the modifications I made to my boat by adding fresh water cooled manifolds and a second red dot heater to defrost my windshield. I had so much hose and heaters to run coolant through the stock pump was stalling at idle. I went to a Flow Kooler pump, which is designed to flow more water at low RPM. This pump is not for raw water cooled engines though, it's made of aluminum. If your system was working before you should be looking at restrictions, air bubbles, loose belt, or a worn pump. I doubt a thermostat would cause this problem. First thing I'd do is pressure test the cooling system. Testers are not that expensive and available at big auto parts stores. If you do want to replace the thermostat it is very easy (and cheap) to do. On the intake manifold near the front of the engine is a housing the thermostat is in. Should be two bolts and a hose clamp for the hot hose running into the heat exchanger. Take you about 15 minutes to change. 190 seems high to me. Mine runs around 140 with a 180 degree thermostat.
John --- On Mon, 6/22/09, Bob & Carmen Harris (36DC) <[email protected]> wrote: From: Bob & Carmen Harris (36DC) <[email protected]> Subject: [UnifliteWorld] Overheating To: "UnifliteWorld" <[email protected]> Date: Monday, June 22, 2009, 4:04 PM We have a problem with the port engine (Crusader 350 big block Chevy) overheating slightly at idle. It may go to 200 deg F on the gauge Once we hit 1000 RPM or more it quickly drops down to steady 190 degree range where it has always been. I changed the impeller and installed a new raw water pump, but it didn't help Next I was thinking checking the heat xchanger (once I remove the end- cap, will I need new seals?) or replacing the thermostat. Is it easy to replace a thermostat and could that caiuse the engine to run warm at idle? The risers/manifolds are 4 years old --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "UnifliteWorld" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/UnifliteWorld?hl=en -~----------~----~----~----~------~----~------~--~---
