How to replace coolant heat sensor on 1998 saturn

On my daughters sl2 it is on the driver side. A note though, there are 2. Crazy i know, one above the other. One goes to the guage and one to the computer. When my son had the car it would not stay running at idol, had to rev the engine to keep it going. The engine would shake hard too, what through me was the guage in the care read fine but once i found the sensors the one looked fine the other looked like it split in half. Hope that helps

Check your coolant level. Most causes of no heat are low coolant levels or blocked heater cores. If it overheated and has no heat I'll beat its a low coolant level. Check for leaks. Just because the gauge didn't go all the way up doesn't mean much. Those cars trap air in the cooling systems when the level gets low. That will cause those problems. Check for leaks and if a repair is made I also recommend a termistat.

check overflow jug for other sensor

The engine coolant temperature sensor is mounted in a coolant passage located in the cylinder head.

both pending were located

Engine coolant temperature sensor.

the rear or #2 heated o2 sensor is under the car right after the cat converter,,,,about under the radio area,but under the car,,,,,youll see it

Inside the coolant reserve tank there is a sensor for coolant level.


Over time,this sensor can get stick.


Inspect the coolant reserve tank for crack or leak.

Locate the coolant level switch/sensor and soak it in clean warm water.

Make sure it's free to move up and down the float path.

Top off the coolant tank with coolant only.

On the SL2 (DOHC), there are two coolant temperature sensors located on the left-hand side of the cylinder head, near the upper coolant hose. On the SL2, the upper sensor with ONE WIRE controls the temperature gauge in the dash. The lower sensor with TWO wires provides input to the computer. They are not interchangeable. Here is a tip you will need a 14mm deep socket or box wrench. The new sensor may require a 13mm socket or wrench, depending on the manufacturer. Good luck and hope this helps. Keep me posted.

You can replace the fuel pressure regulater in the car.