stevie_b Posted June 6, 2015 Share Posted June 6, 2015 My newly-acquired Ford CMax runs cool: the temperature needle gets to 1/4 of the way up the gauge. This points to a thermostat that's stuck partially open. But then I ran the car stationary for several minutes, and the electric radiator fan cut in when the temp needle was at the halfway point. I find this last point a bit odd. If it's just the thermostat that's faulty, surely the electric fan shouldn't cut in at the halfway mark (which is what cars usually run at on their temp gauges, as a rule of thumb). Any ideas? Quote Link to comment Share on other sites More sharing options...
markylee Posted June 6, 2015 Share Posted June 6, 2015 I think it cuts in to stop it going over the half way mark, probably thermostat. Quote Link to comment Share on other sites More sharing options...
Benjy Posted June 6, 2015 Share Posted June 6, 2015 Stupid question - Air con wasn't switched on was it? Quote Link to comment Share on other sites More sharing options...
stevie_b Posted June 7, 2015 Author Share Posted June 7, 2015 I think it cuts in to stop it going over the half way mark, probably thermostat. Is it unusual for an electric fan (not an engine-driven fan like the supra has) to operate at normal temperatures though? I thought those ones only kick in when things get hot. My assumption here is that the temperature gauge should be at the half way mark under normal driving. I don't know if that's definitely the case on the CMax, but it's been the case for every other car I've driven. If the thermostat is faulty and I change it for another one that holds the temperature at the halfway mark, that'll mean the fan will run during normal driving, and that doesn't seem right. In turn, that means either my assumption about the 'stat being faulty was incorrect, or that there are multiple problems on the car (temperature gauge, temperature sensor, ECU fault, etc...). Stupid question - Air con wasn't switched on was it? The aircon was definitely off. Quote Link to comment Share on other sites More sharing options...
Benjy Posted June 7, 2015 Share Posted June 7, 2015 Probably needs a coolant temp sender and a stat then. It's not massively unheard of mate Quote Link to comment Share on other sites More sharing options...
Benjy Posted June 7, 2015 Share Posted June 7, 2015 You're only in Hampshire I see. If you're ever over this direction buddy, I can always plug it in for you and have a look at the data. Quote Link to comment Share on other sites More sharing options...
stevie_b Posted June 7, 2015 Author Share Posted June 7, 2015 Thanks Benjy, I appreciate it. I might get hold of a temp sender (depending on price!) to see if that makes a difference. Quote Link to comment Share on other sites More sharing options...
Ian C Posted June 12, 2015 Share Posted June 12, 2015 The fan will kick in when stationary, that's quite normal. It won't kick in when driving as the airflow from driving will provide the cooling airflow that the fan provides when stationary As for the car running cool, check it doesn't have an oil thermostat as well as a water one. They can fail too. Quote Link to comment Share on other sites More sharing options...
stevie_b Posted June 12, 2015 Author Share Posted June 12, 2015 To clarify, is it normal to have the fan kick in whilst stationary but (and here's the crucial bit) when the temp gauge needle is bang in the middle? My experience with other cars is that the electric fan kicks in when the gauge reads roughly 2/3 or 3/4 to the red mark. Quote Link to comment Share on other sites More sharing options...
Benjy Posted June 12, 2015 Share Posted June 12, 2015 The gauge will always stay in the middle. If it goes up, you've got issues. The fans will kick in whilst stationary to maintain the temperature and keep the gauge constant as to not worry the driver. Quote Link to comment Share on other sites More sharing options...
stevie_b Posted July 7, 2015 Author Share Posted July 7, 2015 Having changed the thermostat, the car now runs at the correct temperature. I did run it for a while stationary to se if I could make the fan kick in (and to observe what temperature it kicks in at), but the temperature needle didn't budge (which I'm pretty pleased about) and I got bored and gave up. Thanks chaps! Quote Link to comment Share on other sites More sharing options...
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