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HI there,

I am wondering whether I need to get my thermostat looked at in my 2006 Mazda3 manual hatch. The behaviour is unusual, and when the car is at higher revs the engine cools down. a typical morning commute from Newlands to WLG central will look like this on the gauge: First 4 kms, mostly sitting at 2,200-3,000 rpm, the gauge will stay below C, and when I reach the more congested traffic and rpms goes down to 1,500-2,000 the gauge will quickly move up to 1/4 of the way up, and will stay there until I come to a stop at lights, where it quickly shoots up to halfway. If I get my revs up to 3,000 rpms again (i only have 5 gears) it will go back down to 1/3 or 1/4 of the way up the gauge. On my most recent open road trip it was at halfway when stuck behind a truck going up the Saddle road, and when I passed it and completed the Saddle road the gauge was sitting bang on C. To me it seems like the car gives the car too much fan/coolant when the revs go up (which I can't help), and I am wondering whether I need to get this replaced. My handbrake cable needs tightening so I could kill two birds with one stone.

Many thanks,
Dave

Hi Dave,
Yes this sounds very much like the thermostat is jammed open, it is definitely best to get It checked as the car will be running too cold a lot of the time and could even be using more fuel. Yes get both items checked off at the same time.