Changing your car’s thermostat is among the basic auto repair tips that you can do yourself and save money on. The thermostat is what keeps your car from overheating. It does this by regulating the flow of coolant through the engine block. It also helps heat your car in winter. Changing your thermostat, is a very simple way to save on your car’s maintenance costs.
Always wait until your engine is cool before working on any part of your car’s coolant system. Under normal usage, the coolant in your engine will be both pressurized and extremely hot. Removing the radiator cap or otherwise releasing the coolant can result in an explosive release of scalding hot liquid and serious burns.
You should have the tools you will need on hand before you start. In addition to the new thermostat, thermostat housing gasket, and replacement coolant, you will require a small socket wrench which fits the bolts of the thermostat housing, a small adjustable wrench, a small scraper or wire brush, and a two-gallon (nine-litre) bucket and a drip pan for the coolant. You will also need a waterproof sealer.
To find your thermostat, trace the top hose from your radiator until you find the thermostat housing, which is shaped like a triangle and bolted down. The most common location for a thermostat in most North American vehicles is at the front of the engine. Keep in mind; however, that four-wheel drives and many Japanese and European models orient their engines differently.
Next you should drain your cooling system. Your vehicle should be level when you do so. There should be a plug at the bottom of the radiator: place your bucket under it before you remove it! Place the drip pan under the part of the engine that contains the thermostat. This will catch the coolant run-off when you remove the thermostat housing.
The key to the next steps is to remember that everything goes back on the same way that it came off (this is a great auto repair tip that will come in handy a lot). It may help to be holding the replacement thermostat ready in your spare hand while removing the old one, so as to maintain the orientation.
Move the hose out of your way. Take out the bolts holding the thermostat housing in place and remove the housing. It should come loose fairly easily. If not, carefully remove any remaining gasket and sealant with the scraper until it does. Too much force can cause the housing to crack. Clean off the port and all the surfaces with the scraper to get rid of the remnants of any old sealer or gasket.
You should be capable of removing the old thermostat easily. Replace it with the new thermostat, maintaining the same orientation. Double-check the numbers on the rim of the housing to make sure you have the correct part number.
Seal the gasket to the engine (over the thermostat), and the housing to the gasket. The bolt holes on both should line up. When everything is properly placed and sealed, bolt it in. This is easier if you only lightly bolt at first, enough for the housing to remain in place, and then tighten separately. Be careful not to over-tighten the bolts.
Restore the plug at the bottom of the radiator, and empty out the drip pan and replace it. Start your car and refill the cooling system with coolant, according to the specifications in your car’s manual. Watch your engine temperature indicator. The car’s temperature should rise gradually and evenly. Check your engine hoses and connections for escaping fluid. If any coolant still empties into the drip pan, you have a leak somewhere. Now is the time to identify it and seal it.
Take the car for a short test drive to confirm that the engine temperature remains steady. Upon returning home, check one last time for leaks. Some leaks don’t show up until the car engine has been working for a while.
It is ideal to change your thermostat once a year, at the same time when you change your coolant.