Coolant Level Sensor?

**MechEngineer17** · 2 Weeks Ago

Alright, guys, I have read about this a million times, but I am stumped.

So, one day, my low coolant light came on.

When I got home, I checked under the hood for a quick inspection, and it looked okay.

I let the truck sit overnight, and the radiator hose was soft in the morning.

The reservoir had no pressure, and the coolant level was acceptable.

The light stayed off for a few days, then randomly came back on.

For the last two days, it seems to come on only after about 20 minutes of driving the truck, but nothing is low.

Maybe the sensor is getting heat-soaked, and the float is.

Has anyone had an issue where the light only comes on after driving for a while, but when the truck is off, the levels are fine and not losing any coolant?

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**AK Bob** · 2 Weeks Ago

I haven’t experienced the issue you described, but this video has some good information about coolant level sensor testing.

You could also try flushing out the tank if the magnet is sticking.

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**MechEngineer17** · 2 Weeks Ago

Thank you, that is some good information.

I just ordered the part (no one local has it in stock), so I will take it apart this weekend to test it and then replace it.

If that doesn’t fix it, I will most likely move to the reservoir getting replaced next.

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**AK Bob** · 2 Weeks Ago

That sounds like a good plan.

Please keep us posted.

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**MechEngineer17** · 2 Weeks Ago

Originally Posted by AK Bob

That sounds like a good plan.

Please keep us posted.

Will do that!

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**bajaben** · 2 Weeks Ago

Mine was doing the same thing.

I ended up replacing the coolant reservoir tank.

It turned out that the magnet float would stick.

It built up a bunch of grime over the last ten years and would stay stuck in the down position.

It's k8nda, and it's a pain to change out.

I had to unbolt the battery tray and move it forward about an inch to gain enough clearance to remove the old tank.

Also, a side note: drain the coolant about halfway.

I could get away with pumping the coolant out of the reservoir but spilling about 2 gallons of coolant.

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**xblazex** · 2 Weeks Ago

Originally Posted by MechEngineer17

Alright, guys, I have read about this a million times, but I am stumped.

So, one day, my low coolant light came on.

When I got home, I checked under the hood for a quick inspection, and it looked okay.

I let the truck sit overnight, and the radiator hose was soft in the morning.

The reservoir had no pressure, and the coolant level was acceptable.

The light stayed off for a few days, then randomly came back on.

For the last two days, it seems to come on only after about 20 minutes of driving the truck, but nothing is low.

Maybe the sensor is getting heat-soaked, and the float is.

Has anyone had an issue where the light only comes on after driving for a while, but when the truck is off, the levels are fine and not losing any coolant?

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If you want to know if it's your sensor or not take the connector from the coolant tank located on the bottom and put a jumper wire in it.

Doing this will tell the truck the coolant is filled correctly, and the light will turn off.

If the light stays on then your problem could lie in the harness side.

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**OneTon** · 2 Weeks Ago

I had the same issue here.

Replaced the sensor with no luck.

The magnet in the tank is sticking.

I just jumpered mine and let it rip.

I have the hood open enough that I don't need to rely on a sensor or light to tell me my coolant is low.

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**Dallasm12** · 2 Weeks Ago

Yeah, I did the same on one of my trucks.

Just jumped the wire and never looked back.

It was just wild to me how nasty the reservoir tank was. I knew that the only way to truly fix it would be to replace it, but I didn't want to spend that much.

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**MechEngineer17** · 1 Week Ago

So, here's a quick update: you guys all so far are right.

The sensor was not the issue.

I put in a new one with no resolution, but the light is still intermittent, so next, I’ll just replace the reservoir.

I can see some sediment in the bottom, assuming it’s sticking.

It’s due for new coolant, so I’ll do the coolant and tank in one shot.

I know the truck is not low on coolant.

The light dinging is annoying, and I’m not to the point of buying a jumper yet, LMAO.

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