So yesterday and today I got an engine light which turned out to be a low coolant temp code.
Using my reader it showed temps in the 150-180 degrees range tonight when driving but then jumped to 190s and 204 at idle. When I reset the code it won't come on until the next day. 150 degrees coolant temp seems not possible. (outdoor temps 55 degrees)

Using a reader the temp data doesn't look right. It hold the same reading within a tenth of a degree for long periods when all the other data points float around a few tenths constantly.

Based on other threads it looks like a sensor starting to go bad.

BTW:I never have battery issues or a dead battery even after sitting for a while.

Any advice appreciated.










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Is your coolant fully topped off and purged?
Your coolant temperature sensor may be faulty if your fluid is full.

 

As said, most likely to be a failing sensor just just check that the connector has not become loose or contaminated first.

Richard

 

But I would never rule out an airlock…

Yes 150 is low.

 

Cooalnt on my XKRS is alwways around 95C - 203F when warm and does not change much if at all during driving, 150F is far too low as above

 

Probably a broken thermostat.
The rubber seal breaks and prevents the stat from closing.
very common.
Could also be the internal housing stat flange has broken.
not too bad to check