Is your 350 engine sporadically running hot? If there seems to be no loss of coolant and the engine still gets very hot, chances are your thermostat needs to be replaced. Follow the steps below to protect your engine from permanent heat stress and damage.
Locate the clamp on the end of the hose that connects the thermostat housing and the radiator. Loosen it and push it up towards the radiator. This may require the use of pliers or vice grips.
Disconnect the hose from the thermostat housing and move it out of the way. Leave the other end of the hose connected to the radiator. It is normal to lose a little bit of coolant during this process.
Remove the thermostat housing by locating the two bolts holding it in place. Use an open-end wrench to turn bolts in a counter-clockwise direction. Apply even, gentle pressure until it is removed. Do this carefully to avoid damaging the gasket that seals the housing to the 350 engine.
Remove the thermostat, which is clearly visible after removing the housing, and replace it with a new one specified for the 350 engine. Check with your automotive supplier to ensure you have the proper thermostat.
Replace the thermostat housing and tighten the two bolts in a clockwise direction. Be careful not to over or under tighten; either can cause coolant leakage and extreme heat stress to the engine.
Reconnect the hose from the radiator to the thermostat housing. Twisting one direction, then the other, in a small radius, will help ensure a good and tight fit. Bring the clamp back down the hose and tighten.
Remove the radiator cap and start the engine. This will release the air bubbles in the engine and hose. Once there are no more bubbles visible, replace the radiator cap and fill the coolant reservoir.
