The temperature where I live is in the fifties Fahrenheit and it seems like its taking a very long time for the engine to warm up and exit open loop mode. I have a 97 Mazda Lantis 323 and I'm thinking that maybe the thermostat is stuck open. Is it normal for it to take 15 minutes for the engine to warm up at that kind of starting temperature ?

1 Answer 1


I think you are on the right track with the thermostat. No it should only take a few minutes max, even in colder temperatures for it to warm up. The thermostat is a cheap part to change and usually pretty easy to get to, so I don't think you are going to lose much by changing it out.

  • You won't believe this, but when I pulled off the thermostat housing, there wasn't one. Things are working much better now that there is a thermostat, although I suspect there are some other problems still. Commented Feb 2, 2015 at 15:07
  • @RobertS.Barnes ... There is usually two reasons why someone removes the t-stat: 1) to alleviate cooling issues; 2) with a false understanding that they are actually gaining some horsepower in the process. In deference to the second, too bad with modern fuel injected engines you are actually hurting performance unless you also provide a tune to make use of it. Glad you found/fixed the issue! (Well, at least one of them, lol!) Commented Feb 2, 2015 at 17:10

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