I have an '08, R55. Yesterday, 57 degrees outside, on a drive on 2 lane roads I got an engine heat warning lamp. (I really miss gauges)

I turned on the heat to high, only to find I had no heat either.

I checked the coolant bottle and it was at the bottom.

This morning, I added coolant, (per- https://wiki.bentleypublishers.com/d...R56+N12+Engine )

I was not able, however to find the elusive bleed screw, (until just a few minutes ago) I did add coolant to the line, and start the car, let it warm up, and once the engine got to operating temp. (estimated since I don't have a gauge) the coolant level rose in the bottle almost to the amount I added.

Also note, at no time, including yesterday with the high temp warning, did the cooling fan kick on.

Any good ideas or experience? In the mean time, I will bleed the system and recheck. I hate not knowing how hot the engine is while I am doing this. :(

 

Update. . .
Managed to find the bleed screw. I believe I vented the air out, though it was hard to tell if anything was happening, though the coolant level in the bottle did slowly drop. It needed another quart, which makes 2 total. I backed the screw out quite a bit, until I thought it would fall out if I kept going, then turned it in about a full turn. What a major PIA that would have been should it had fallen out. You can already barely see it, let alone recover/reinstall it!

So, there you have it. I'm going to have to watch and see what is going on with the cooling system, and if there is a leak/more coolant loss.

Cheers