I have an interesting issue with my coolant temps. I'm running an Ultra gauge so I can stay on top of temp and boost. I live in Houston and it's always hot during the summers - typically 92-95f with all the humidity. The car runs around 222-226f in traffic and about 221 on the highway. I don't get any overheating issues with it, and reading through forums this looks reasonable (is it?). However, I was doing some 'spirited' driving on the freeway and was cruising at about 4000 rpm. I noticed that the temp went down to 210 during this (and even lower). When I got off the highway it bounced to 228 before settling back at 226 (in traffic again). During the rest of my drive I tested my high rpm theory and drove around 4k. The temp went much lower again. So, is this normal for minis? To me it indicates that the water pump isn't being driven correctly at lower rpm. I'm about to do a coolant flush and put fresh mini coolant in to see if that was the issue. Presently, all fluids are topped off and I did bleed the system.

 

The water pump speed varies with engine speed, which means the flow through the cooling system changes with engine speed. More flow, better cooling. Completely normal.

 

Ok. PHEW!! Thanks!