My 1994 Suzuki Swift Sedan 1.3L with 280,0000 miles has been running cold for a while now.

I can't get my self warm with the heater in the mornings when there is frost. It surges climbing up a mountain. The most annoying thing is that the indicator for the temperature needle will go up and down as the car accelerates and decelerates from middle to low in steps. I thought the old thermostat would be stuck open but it was not. I am unsure if there is some small problem that is creating this issue.

Does anyone have a solution to this issue?

I used this procedure to install and remove the thermostat from the chilton book

Pic of old thermostat enter image description here

this is after getting answer. So found the sensor near/at thrermostat housing. one wire comes of it. grounded the sensor to the chasis with alligotor clips. Flip the key swittch on/off and it did climb the temp coolang gauge to hot.

actually after just messing with the connection it started to work alone. It was just corroded! :) the outside sensor's connnection

  • going to try to flush the system to see if that will work. following the procedure from chevy cobolt wich is better documented than this asian/ foreing car. But flushing the coolant I dont think will do anything bc once runninng it the reserve is still full. Jun 8, 2016 at 19:52
  • Are you loosing coolant? What year is the car? how many miles?
    – rpmerf
    Jun 8, 2016 at 20:47
  • @rpmerf no not loosing coolant. its a 94. about 280,0000 miles. Its still going. It just has a few ticks. Its driveable .Im guessing its something weird. I am pondering on buying a way newer car but I am not sure he will completely break down anytime soon. Jun 8, 2016 at 20:51

1 Answer 1


The heater core may be plugged, if fluid is full and there aren't any leaks. Check this when the engine is hot, if one hose is cold or warm and the other is hot the heater core is plugged.

The temp gauge fluctuations may be an electrical issue or there's air in the system. If you backprobe the temperature sensor have someone rev the engine and look for fluctuations in voltage. You should also do this at the cluster to confirm wiring.

As to the surging going up a mountain, it may be a bad BARO/MAP sensor. Just idle speculation as you'd have to look at voltages/scantool data to confirm this.

  • Temp sensor is having issues!!. it has one wire. Grounded it to to chasis and got the gauge inside the car to climb to hot. ofcourse one needs to not leave it there or damages the gauge. just fliped on/off the key. I looked what is wrong with heating later. I thought it was one to be one problem that fixed evrything but is convuluted problem. Jun 12, 2016 at 21:56

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