Engine cutting out when cold then running colder than normal

Engine cutting out when cold then running colder than normal

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SilverSixer

Original Poster:

8,202 posts

152 months

Monday 23rd March 2015
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Wonder if anyone can help diagnose a problem I'm having with my Mazda 6, it's a 2006 Mk1 (facelift) 2.0 petrol auto (147PS model).

When the car is first started in the morning, it starts fine then the engine cuts out the first time I slow down sufficiently to either take a sharp bend or come to a halt. Happens up to three times each journey. Very annoying as I can't avoid some very sharp bends and Give Ways shortly after leaving home. It's an auto so dipping the clutch and revving isn't a work around.

Then, if I'm getting up to motorway speeds, the engine remains cold - that is to say the temp gauge needle shows about 1/3rd rather then the halfway I'm used to. In stop/start town driving it gets a bit warmer, but still not quite up to the halfway mark on the gauge.

The car had a new battery a couple of moths ago, but other than that no other changes. I've only noticed this behaviour since the new battery, it started immediately the battery was changed. The old battery had gone totally flat.

Does this sound like a thermostat problem or a coolant temperature sensor or something?

Doesn't sound like a big deal, but it seems to be hammering the car's MPG.