Check without removing the thermostat
1. Before removing and testing the thermostat, make sure that engine cooling problems are not due to insufficient coolant or loose drive belt tension. Make sure the indicator on the dashboard is working.
2. If you notice that the engine takes a long time to warm up to operating temperature (according to the indicator), the thermostat may be stuck open. In this case, the thermostat must be replaced.
3. On the other hand, a long warm-up may be due to the lack of a thermostat. It could have been done on purpose or unintentionally (forgot to install after repair). Do not drive the car without a thermostat. The engine management system will keep the engine in warm-up mode for a longer time. During this time, the engine will consume more fuel, and the exhaust gases will contain more harmful impurities.
4. If the engine overheats, feel the upper radiator hose. If it's not hot and the engine is overheated, the thermostat may be stuck in the closed position. The liquid does not enter the radiator and circulates in a small circle. In this case, replace the thermostat.
5. If the upper radiator hose is hot, the thermostat is open and fluid is circulating normally through the system. In this case, read the recommendations given in Section Troubleshooting Introductions.
Test with thermostat removal
1. Remove the thermostat (see Section Removal and installation of the thermostat).
2. If the thermostat is open at room temperature, it is defective and must be replaced. 3. For a rough test of the thermostat's performance, hang it on a piece of twine in a container of water. The thermostat must not touch the walls of the container. Start heating the container.
4. As the water heats up, the thermostat should open (this happens just before the water boils). Because the boiling point of water is 100°C, the thermostat may not open fully (talk to Specifications). Remove the thermostat and let it cool down. As it cools, it should close completely.
5. If the thermostat does not open when heated or does not close when cooled, replace it.
Installation
When installing a thermostat, keep the following in mind:
- a) Thoroughly clean the mating surfaces and replace the O-ring;
- b) Place the thermostat into the casing, orienting correctly;
- c) Tighten the cover fastening bolts applying the required force;
- d) Install all hoses in their original places, then fill in the coolant (contact the head Current service).
- e) Start the engine, warm up to operating temperature and check for leaks.