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Saturn Ion 2004 -Coolant Level Sensor


I’ve been trying to research this problem, and hope someone can help me here. I listen to the show when I can, but can’t find an answer for this question. (google, car talk any where)

My coolant light goes on, it started in winter in February, and continues to yell @ me (checked the coolant and wires all is fine). I went to have it looked at, the mechanic says I need to get the Coolant level sensor replaced, but to do this he says it’s part of the coolant reservoir, hence I need to replace both. Which will cost like $300 bucks, which I don’t have.

Question: is this true? do you have to replace the reservoir to replace the sensor? I can’t find an answer anywhere.

Thanks in advance. Hope someone can help. :slight_smile:


It would appear the coolant level switch is part of the coolant reservior.

If you go to, you can get the reservior with the switch for $45.00.


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Now I just have to find a mechanic :slight_smile:

Seriously, it may not be too difficult to try that yourself. Usually those tanks are held in with easily accessible hardware, maybe a bolt or two, possibly a clamp to hold the hose on but that’s it. You can probably get a repair manual for your car on ebay on CD for $5 that will show you how to remove it. Maybe get one, just to see if you can figure out how to do it.

You’ll save yourself easily a hundred bucks that you can do something fun with to reward yourself.

I just changed the tank on my car. It was less than $60 at O’Reily Auto Parts. There is a clamp that is difficult to get to but it can be done. A tab goes on a bolt with a nut BUT there is a bracket for a fuse block over this tab. This was difficult to accomplish but I got it done. Now every time I start the car the coolant lights come on but when I hit the reset it goes off. I am now looking for a way to reset this so it doesn’t come on every time I start the car.

You may need to find a shop with a Saturn scan tool to reset it properly. But you could try monkeying around a little if you wanted to experiment. It probably works using a switch attached to a float. That kind of switch is usually open with low coolant, and closed if the coolant level is ok. You’ll have to verify by visual inspection and using an ohm meter which way it is configured in your case. If there’s a problem with the coolant level switch, it would be too high resistance when it is supposed to be closed. It should measure less than 1/2 ohm when closed and infinite ohms when open.

You might could connect a properly fused jumper wire in place of the switch temporarily. That should make the system think the coolant level is always ok. If that solves the warning light problem, then you know there’s something wrong with the switch.

Sometimes disconnecting the car’s battery for an hour, then reconnecting will cause all the computer’s to reset. The problem is that this sometimes causes other problems.

You probably already know this, but the warning light is probably supposed to come on when you turn the key to “on”, and stay on for a few seconds as you start the car, before going off automatically. so double check it doesn’t go out by itself so you don’t end up chasing wild geese fixing a problem that doesn’t exist.

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