Coolant Level Sensor Blew Out

Luckily this happened 1/4 of a mile from home.

So I’m sitting at a red light and I hear a loud “bing” sound. I thought something in the suspension snapped, but I pulled away and all was well.

I get home in the driveway and hear that dreaded gushing and dripping of fluid; there’s coolant everywhere. I popped the hood and the coolant level sensor is missing and coolant is running out of the hole.

What the hell.

Anyways, I find the sensor behind the radiator and the retaining clip is still on it (it was properly seated when I put it on). I get the sensor cleaned up and reinsert it, but it feels looser than I remember. I put the retaining clip back on and it seats behind the flange on the radiator tank, but still feels a little loose. I’ve given it a decent tug and it doesn’t come off.

Now, I haven’t refilled the radiator and started the car yet, but I’m wondering if anyone has experience with this. Is it just going to pop out again? Should I just buy a new sensor? Replace the O-rings on the sensor and try to find a new retaining clip?

There were no leaks from the sensor connection prior to this happening. It’s a 90’s GM radiator/sensor setup.


Meh, I wiggled it a bit and it came right out. SOaB, $50 part that ain’t broken.

If it will not stay, it’s broken. Either the sensor or the mounting hole in the radiator.