Thermostat and Water Pump Problems
As mentioned, many components can be transferred from the old engine to the new one, including the power steering pump, the AC compressor, alternator, radiator and more. Hoses that are in good condition can also be reused. However when performing an engine installation, make sure that you don’t transfer the old thermostat and water pump. Replace those with new parts; never reuse the old ones and it’s always a good idea to inspect any used car engines for sale, getting the true value.
Engine Installation & The Cooling System
The car’s cooling system is essential. Without a reliable system, the engine will overheat and possibly be destroyed. Make sure you fully inspect the cooling system before installing any of the components on the new engine. Check the following:
Cooling Fans
Cooling Fan Motor
All coolant hoses including the oil cooler hoses if they will be reused
Fan clutch, switches and wiring harness
Fan Relays
If any of these components are not up to par, replace them rather than reusing them. As a note, pay close attention to the wiring, as rodent/pest damage can be a real issue here.
You’ll notice two pretty important components that weren’t on the list of things that need to be inspected. Those are the thermostat and the water pump. Replace these, rather than reusing them. The thermostat is pretty easy to replace – just take out the old one, remove the gasket and replace them with new parts. The water pump should also be replaced rather than reused. Because you’re putting in a new engine, replacing the water pump isn’t the chore it is on an in-vehicle engine.
Why not reuse the old water pump? Besides the fact that it’s a relatively inexpensive part, there are some very good reasons not to reuse the old pump. One of the most important is the potential for the internal rubber components to have damage from high engine temperatures, especially if the engine died because of heat-related troubles.
If heat killed the engine, that water pump isn’t safe. Impeller damage and impellers coming loose from their shafts are yet more reasons to avoid transferring the old water pump. Interior pump surface erosion (normal over time) will also reduce the lifespan of an otherwise good water pump. Finally, water pumps can corrode due to low levels of antifreeze in the coolant mixture.
Again, as with the oil cooler, replace do not reuse. Before installing the new water pump on the replacement engine, make sure the mating surface is completely clean and free of debris. Install the gasket and then the water pump.
