2000 540i Check Coolant Level Error

[chunkybmw]

thank you for clicking on this thread... here is what’s up

2000 540i 127k 6spd

blew the old radiator driving home (3 months ago)
blew the old expansion tank a few weeks later

replaced both drained system went with blue stuff mixed (previous owner had alien green)

Fan clutch is good according to multiple internet tests.

Got all the air out of system... car drove fine for 15 minutes then light came on



-I smell coolant in engine bay but with multiple blow outs assuming it’s left over smell not head gasket or valley pan leak

-hoses seem good, newish, clips all work

ordered new bleed screw & lower exp tank sensor

ideas like water pump or thermostat?

I know these beasts run hella hot so what am I missing... thanks y’all the best

[dannyzabolotny]

I'd wait until the engine cools off, clean the engine bay, and then add more coolant when the car is cold until the little expansion tank level dip stick is near the top. You often need to top it off after a cooling system replacement, that's normal. In the meantime, I'd keep an eye on the actual temperature by going to secret test #7 in the cluster menu (Google that if you don't know how). It shouldn't really get above 108ºC in most cases.

After you've gotten the coolant topped up, keep an eye out for any other coolant leaks. That's why I suggested cleaning the engine bay, so you'll be able to see traces of coolant leaks easier.

[chunkybmw]

Ok solid I’ll try that
my exp stick comes out like a few inches out from the top...too much coolant?

[jclausen]

Try a new coolant level sensor

[dannyzabolotny]

A few inches from the top? Yeah that's way too much coolant. That'll cause problems either way, get the excess out. If it's still giving you the error then yeah I'd check out the coolant level sensor.

[geargrinder]

Ok solid I’ll try that
my exp stick comes out like a few inches out from the top...too much coolant?

Yeah +++ to what Dannzo says. That very well might be why you blew up the tank and rad. The system needs some air int he exp tank, its' not supposed to be overflowing, otherwise system pressure is much higher and chance of blowing stuff up massively increases. The "red peener" should just bone its way up to be level w/ the rim of the opening. I mean a wee bit above is fine but inches - WAAAAYYY too much.

Re: the check-level, are you checking the connector under the exp tank? The exp tank includes a new sensor inside of it so that should be fine, most likley you have a contaminated or bad connector underneath.