coolant light stays on a bit ; goes away

[gymkata]

I get the coolant level turning on when I start the car and then it goes away. It says, read Owner's Manual. Doesn't stay on for long. Is this a warning sign of anything or what?
Noticing that also when I start the car as it's getting colder that the car makes a growling sound when it initially starts until it warms up.
Did this last year when it was really cold out here in the Midwest (neg temps everyday for a week)..
wondering if it might be the water pump or oil pump...
thanks in advance.

[BMWDriver]

Time to check your coolant level.

[BMWDriver]

I think the coolant level cannot be checked by sensors while the fluid is flowing and hot, hence why it would only warn you on ignition. Water expands when hot.

[e34.535i.sport]

Check the level before you get in tomorrow... Last time mine chimed up coolant level when I got in I checked it and it was nearly empty due to a nice hose split. If the level is fine possibly a dodgy sensor?

[whiskychaser]

I think the coolant level cannot be checked by sensors while the fluid is flowing and hot, hence why it would only warn you on ignition.

x1.
So bear in mind if you lose all your coolant, the 'low coolant' sign will only come on just after the engine stops -cos it has seized. Handy feature

[uscharalph]

Most likely it's the coolant level sensor, but when it goes on in the morning, I get out of the car and check it anyway.

[BMWDriver]

Here's part of a post I had found on bimmerforums:

Since so many have commented on bad coolant sensors, here's a tip:

The coolant sensors aren't going bad. The connection between the sensor and the wireing harness is. Next time you change it, clean (and i mean wire brush clean) the contacts on the sensor plug. Then, coat the prongs in dielectric grease to ensure a good connection.

I did this a year ago after constant coolant sensor replacements and I'm happy to report it hasn't been an issue since.

[Scott C]

Here's part of a post I had found on bimmerforums:

Since so many have commented on bad coolant sensors, here's a tip:

The coolant sensors aren't going bad. The connection between the sensor and the wireing harness is. Next time you change it, clean (and i mean wire brush clean) the contacts on the sensor plug. Then, coat the prongs in dielectric grease to ensure a good connection.

I did this a year ago after constant coolant sensor replacements and I'm happy to report it hasn't been an issue since.

Ditto - I used pliers to squeeze the pins a little together so the fitting was tight.... Of course I did this after replacing the sensor and NOT fixing the problem (would randomly come on)