Engine overheating warning

[ADH]

Hi guys, I have 2001 picasso hdi, I'm getting a engine temperature warning flashing up on my dash, but, only when I'm using AC.amy thoughts or cures would be good . cheers

[wheeler]

I bet your cooling fan is not working. First thing to check is that it turns freely. If it’s turning freely you will need to check the cooling fan circuit. Normally cooling fan problems are caused by corroded speed control resistors.

[ADH]

The fan is working ok, I only have the problem when I use the A/C, and then it only flashes every few seconds, running the car normally the temp stays normal.

[wheeler]

Just to be clear im talking about the cooling fan on the radiator. Are you saying when you switch the A/C on your radiator cooling fan is coming on as normal & running constantly at mid speed?
Any time i have ever seen this issue its been related to a cooling fan problem.
How did you test the cooling fan operation?

[ADH]

No not an issue with the cooling fan,it seems to be working fine. I get the warning flashing up even first thing in the morning when the engine has just started and cold. I think a sensor or something is getting confused, as am I lol

[wheeler]

Previously you said this fault only happened when using the A/C? In this case I would say a cooling fan issue. If the fault also happens when the A/C (or demister) is not operating then just sounds like a temp sensor issue.

[ADH]

Well I don't know what's going on now. Yesterday we went out in the car and had the same problem, except the carafe a rattling noise then belched out a huge amount of blue/grey smoke and stopped.mechanic has checked it and thinks it's an electrical problem

[ADH]

Was the coolant sensor at fault

[ADH]

So a few weeks ago I changed the coolant senior and the problem disappeared,but true to form it's back. Still only get the warning when AC is on