how do I replace a thermostat on a Nissan Maxima?

ANSWER : Hi, thanks for writing in. The thermostat housing and the thermostat itself are two different components and do not necessarily need to be replaced together or at the same time. The housing is just a piece that covers the thermostat that also has an opening for a radiator hose which is where the water enters and exits the motor. The housing may need to be replaced at times if it is cracked or leaks severely, however they are indeed two different and distinct pieces.

Hope this helps and best of luck.

ANSWER : Hi there. As far as I’m aware, the valve covers on a V6 3.5 Liter Nissan engine are made of steel and not plastic or a polymer. If the valve cover was a strong polymer (or plastic), the valve cover gasket would still be separate from the OEM valve cover and could be replaced. However, the spark plug O-rings inside the valve cover are not replaceable, so it is recommended to replace the valve cover and gasket at the same time. This video should explain what I’m talking about.

ANSWER : The thermostat is located on the front of the engine. The engine is mounted transversely so the front of the engine will be facing the passenger side and the thermostat in near the alternator. The battery must be disconnected and coolant must be drained first to prevent spilling coolant on electrical components and causing a short. From here, items can be removed until access to the thermostat is acquired. Consider hiring an experienced technician like one from YourMechanic who can come out and perform the thermostat replacement service for you at your leisure.

ANSWER : Hi There,
You may not necessarily need to replace the thermostat as a function of replacing the radiator. If the temperature gauge now remains at a normal level (in your case, below half way between C and H), you should be fine. You will want to pay attention to the fluctuation to be sure that it does not rise above the normal level.

ANSWER : The thermostats on this engine have an electrical heater element intended to help the engine warm up faster. Many thermostat housings for this engine are plastic – from different suppliers. The plastic housings tend to leak around the heater wire plug, and corrode. Engine management "sees" the bad connection from corrosion to the thermostat heater as a failure, setting a problem code for ’replace the thermostat’.

Replace the thermostat with one with a metal housing, and the problem should go away. I would recommend having a thermostat replacement completed by a mobile, professional mechanic, such as one from YourMechanic, to diagnose this problem, get an accurate assessment of damage and cost estimate for repairs.

ANSWER : Hello – this is a judgement call. It is common practice, but not a "standard", to replace the thermostat when replacing the water pump. This is mainly due to access to both easily when replacing either one, and the relatively low cost of a thermostat. Thermostats do not have "wearing" items like the bearings in a water pump, and can outlast a water pump. They can, and do, however, fail unpredictably (close down tight) – sometimes. I have experienced this personally. I encourage my friends, relatives, students, and customers to replace both when repairing either – save the labor cost of a 2nd repair, and the somewhat unusual cost you have sadly experienced.

ANSWER : I have verified that the thermostat is only replaced with the housing since the housing and thermostat are built together and not sold or replaced separately.

ANSWER : Trace the top radiator hose back to the engine. The top radiator hose will be connected to (or near) the thermostat housing. On the 2.0 engine, look for a plastic housing with multiple hose connections just to the left of the battery. You can request engine cooling thermostat and the responding certified mechanic will get this taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.