Anyone have situation where the sl engine temp fluctuates between 80 and close to 100 degrees depending on driving?

I have a 2004 SL500, live in So. Fla. My gauge runs between 85-96 degrees. If I am stopped in traffic, the gauge will read one mark below 100. Dealer says this is normal.

Thanks, just wondering if the v-12 and the twin turbos actually are working fine. Any 600 owners report this problem. let me know. I am due in for service tomorrow and wanted to go over with them...