Hi,
My fiesta's temp gauge is reading unusually low, especially when travelling at motorway speeds. The needle drops just off the "normal" area of the gauge, which hasn't always been the case. Furthermore when stuck in traffic in hot weather previously the needle would creep up until the cooling fans kicked in, which it doesn't do any more - the needle barely gets past the mid-way point of the "normal" area on the gauge.
I'm wondering if this is likely to be indicative of a change in the characteristics of the thermostat, or if the temp senders are tired and in need of replacing.
Do thermostats change their opening temperature with time?
Cheers,
Fiesta man.
|
|
The sender for the guage, and the sensor for the fans are almost certainly different, so if the guage shows low and the fans aren't coming on, probably genuinely running cooler, O wouldn't worry, what may look a lot on the guage is probably one a degree.
|
|
You're correct - the gauge and ECU (which activates the fans) use different senders.
|
|
|
|
The thermostat could have stuck open. Some fail safe this way. Happened in my old SAAB. Take out the thermostat and hold in in nearly boiling water (on string, or long nose pliers). Put in cold water. Does it open and close fairly quickly and smoothly. Replace for probably a fiver. Use a new gasket, and I like to copper grease the bolts so they do not seize in next time.
|
|
It is almost definately the thermostat that has stuck open, from the symptoms that you describe. Go and buy yourself a new one along with either the relevant gasket or most likely a new O-ring type seal, take the old one out and replace it. I wouldn't even bother going to the trouble of testing it because while you have stripped it down you might as well put a new one in anyway. I am 95% confident that once it has been replaced your water temperature will be correct once again.
|
|
|
|
|
Thermostat controls engine temp.if not working correctly ie stays open engine wont reach normal op/temp.which means temp guage reads colder than it should and will take ages for fan to kick in if it does at all.replace it.any probs after that look elsewhere
|
Hi all,
Just thought i'd add to this thread to say that my Escort is doing the exact same thing as the original poster's Fiesta.
It just started in the last few weeks - at motorway speeds the gauge reaches the very bottom of the 'normal' scale, and in traffic it is about the same.
However i'm sure that i have heard the fans kick in whilst in heavy motorway (crawling) traffic.
Is this still likely to be the thermostat, or just the sender to the gauge, whatever/wherever that may be?
|
|
|
|
![2021 Lexus NX 300h 2.5 5dr CVT [8" Nav]](http://images.honestjohn.co.uk/imagecache/url/crop/90x60/https/assets.heycar.co.uk/t_default-export/f_auto/application_assets/vehicles/pictures/d1b959cb70a916c3aa16b9b838187b3f/2e5a96ddfd598bf95166e4edcbb4e8cd.jpg)
