Fault Codes A8 and 7B Associated Misfire?

[ChiefRider]

I put my new code reader to use today, and am puzzled- I should preface this by stating that I am a dinosaur, much happier working on anything made in the '70's or older...

I recently left my X5 with a shop while away for an extended time. I had asked for the expansion tank to be replaced (preventive maintenance) and for new plugs, in addition to some unrelated work. While there, they replaced upper and lower radiator hoses. The shop had authorization to thoroughly evaluate and we would discuss any other needs- nothing related here was found. I will note there was an occasional misfire when it went to the shop.

Now the misfire is worse- after warm up it can be quite evident above 3500 rpm. Additionally I now get a low coolant warning every so often. A check of the radiator shows the mechanical coolant indicator rise to its full height.

I have kept my use of the X5 to a minimum, and now that I have the NT710 code reader, the only motor electronics codes present are 7B, DME: Activation, map cooling and A8 DME: Thermostat, map cooling, mechanical, jammed open.

Thank you all for any insight!