Cooling system problems 2000 xc70

NugMugs · Post by **NugMugs** » 19 Mar 2025, 22:19

Hello, recently my 2000 XC70 has had coolant boiling out of the reservoir. I've replaced the thermostat and reservoir cap, and found the radiator fan unplugged and I reconnected it. It still bubbles in the reservoir but doesn't burst out. The fan also will not kick on. The temperature gauge moves between operating temperature and cold constantly. Possible head gasket, or (hopefully) something else?

Cross-posting from turbobricks.com (I'll take all the advice I can get

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Post by **scot850** » 20 Mar 2025, 00:02

If the temperature gauge is varying it is most likely the coolant temp sensor (ECT) that is faulty. The sensor fails and also the connector near it also can corrode and become flaky. The coolant temp sensor also controls the engine cooling fan.

Neil.

Post by **abscate** » 20 Mar 2025, 00:06

Resistance specs for the temperature sensor on the 1999-2000 models are here…

Note that the intern who typed it in didn’t understand thst excel sheet columns have to line up. So the resistance data is shifted one block to left .

His performance write up…

~ Good Job Jasper ! We are so proud of you we are promoting you to Junior Intern! ask Siri how to enter data until excel please.

NugMugs · Post by **NugMugs** » 20 Mar 2025, 21:54

I'll see about changing the ECT. The AC pressure switch was broken in half a while ago. I've read that it might also affect the fan.