Last night I bought a used 2003 B2300 reg cab auto w/ 40k miles still under mfg warranty. The problem is that when I was driving home from the dealership about 30 miles away. At a red stop light in the cold night, I noticed the coolant gauge needle was a tad passed the midway point towards the hot region. So I turned the AC on and it moved even further towards the hot side. Although it never reached the red Hot region, it made me worry if this truck has a cooling system problem. The thing is that it dropped back down again after I started moving again. And now I'm worried if I haul cargo on a hot day with the AC on, will the engine overheat?

My question is does your truck engine temp gauge fluctuate past the middle when idling or with AC on? Also, where does your engine coolant temp gauge needle normally sit after the engine is warmed up.

All my other cars were honda's and the temps gauges all read and stay a tad below the midway point even on a hot day in traffic with AC on.

Is this something I should worry about and have it fixed at the dealer right away? Or is this normal and Mazda/Ford designed it this way so that the coolant temp gauge is really sensitive to the engine temperature. Thanks for any help or ideas.


Steven

 

Sounds as if the Fan Clutch is not working. Take the truck back to the dealer and explain what happened. They may replace it for free.

If it is an electric fan (some new trucks have them), than the fan or fan switch is not working properly, again a trip back to the dealer is in order.

 

I agree, dead fan.

The temperature went up because turning on the AC puts extra load on the engine from the AC compressor. If the truck is running hot turn on the heat to get air moving through the heater core.