Overheating Problem

[NASCARMAN]

I have a OMC Cobra/Chevy 3.0 4cyl that overheats at speeds above 25 mph for more then 5 minutes. The engine stays cool below the 25mph mark no matter how long you run it for. I have changed the t-stat and even the impeller. I have even taken off the drivebelt and hand turned the water pump (which seems to be fine and no leaks showing). I have check the inlet screens for blockage (they also looked fine). Is there another screen inside the lower housing that I need to check and/or is there something else I'm missing? I will say she runs great and has in the past.<br />Thanks Peoples

 

[Bluefish]

Re: Overheating Problem

Ck the riser on the exhaust manfold for blockage.<br />Good luck

 

[clanton]

Re: Overheating Problem

After you do as Bluefish said and check waterpump on outdrive, remove the theromstat housing and look for app 1/2 inch hole that allows water in block, I have seen this hole completely close from rust. When this hole is restricted water will not flow thru block.

 

[NASCARMAN]

Re: Overheating Problem

I'm on it guys. I'll let you all know what the outcome is.<br />Thanks, Steve