Perhaps have them check the fan clutch. Mine wen out on a 300e and the temp went nuts!
95 E320 Coupe Black - 70,000 miles with Parchment interior. Stock through out
93 400E Dark Blue - 65,000 miles Sold to my dad
86 300E Gold(yuck!!!) 126,000 miles- Sold, a really fun car with a lot of memories