I installed a rebuilt 350 engine into my 1987 K5 Blazer. The rebuilt engine came out of a 1978 half ton 4x4 truck, the Blazer no longer has TBI. It also has a new radiator, water pump, and thermostat but my Blazer is running very hot. When the Blazer is running at Idle there is little pressure and water flow from the top radiator hose into the manifold inlet. The bottom radiator hose is very hot. I changed the thermostat again thinking the last one could have been defective. I tried flushing the cooling system and refilling it again, that did not work. I have run out of ideas and just need help with anything that I could be missing. Thanks
Is it possible the replacement engine has a water pump that turns the opposite direction from the original ?
The thermostat has to be open to allow flow thru the radiator, have you tried running without a thermostat to check flow ?
SOURCE: 1997 honda civic over temp. Have replaced
Generally if one hose is hot, and the other hose is cold it indicates that they water is not circulating. You could have a defective thermostat. Take the thermostat out and run the engine without it. With the radiator cap off you should see a lot of water moving through. It that is the case, replace the thermostat and you should be ok. If there is no rapid movement of water it may be the impeller on the water pump came loose. This is rare, but it can happen since the impeller is usually pressed on the shaft. You should also check and see if you get a lot of bubbles when the car is running and the cap off. This often indicates a blown head gasket. Hope this helps.
SOURCE: Overheating, Miss Firing, and Running Rough
Smell the coolant. Is there any hint of gas smell? Also look at oil, any coffee coloring indicates problems.
SOURCE: 2000 Dodge Ram Heat not hot, only luke warm @ idle
did you use pure antifreeze if so remove it all and add a 50/50 mixture because antifreeze will not heat up good if its pure. needs water to allow good heat.
SOURCE: 1995 Chrysler Cirrus overheating
Probably not water pump. Engine is notourious for vapour lock.
Cooling system must be blead of air before thermostat will work. Cool bottom rad hose is a dead give away. If you are still watching this forum reply , and I will walk you through the only way I know how to make it work properly. It's actually easy if you do it my way. I have worked on lots of cars , and this engine was the hardest to bleed out. Did one Yesterday , and works perfect.
Testimonial: "I need help on how to bleed the system thanks"
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