Picasso fan problem please help

[Paul-R]

... it overheated once but it has never done it since. i pulled over and waited for it to cool down before starting engine again ...

What were the conditions for it to overheat? Steep hill? Slow/stationary traffic? Or what?

[nomis1981]

i was in country lanes when it overheated there were hills but not steep ones i was doing a steady speed of 30mph the weather was cool too but since that day its never done it again

[RichardW]

They lie about overheating when the temp sensor is going a bit baggy. Ours did it a couple of times - usually when it was stone cold! If you were doing 30, then the fan would have zip effect anyway. How many bars does it normally show on the temp gauge? I think you can't find a fault with the fan, because there isn't one....! The AC not working is nothing to do with this. If you've not bothered, just leave it - in the event that the clutch on the compressor gets noisy then you can put on shorter aux belt to bypass it.

[nomis1981]

The temperature gauge is always on 3 bars before and after that day I'll be taking it on a long drive next weekend see how it goes it's strange how I've never heard or seen it spinning. when I was bleeding the coolant the car was running for a couple of hours and fan never kicked in at all

[Paul-R]

Does the gauge drop down from the three bars when the ignition is switched off? If it does then it is being fed with the wrong information by the ECU. There is more than one possibility for this: faulty temp sender, faulty wiring, corrosion on a connection somewhere, faulty ECU - probably more.

If the gauge sits at three bars with the ignition off then it's faulty in some way. Does the needle move off three bars at any time if this is the case?

[RichardW]

Gauge on this is digital on the LCD display. It shows you what the ECU wants you to see - which may or may not be related to the actual temperature!! The screen goes blank when you switch off.

[Paul-R]

So there's no reading with the ignition off. The question about whether the bars ever move is still valid though.

[nomis1981]

It's a digital display when I turn ignition off it goes off it I turn key so engine not running but display on its stays at 3 bars while engine still hot

[nomis1981]

The faster I go the lower the temperature but can't do with getting caught speeding now that my license is clean

[Paul-R]

So, when engine is cold and you switch on it reads two bars? You start the engine and when it warms up it shows three bars? And if you drive fast enough (30mph? 50mph?) it drops down to two bars?

[nomis1981]

No when engine is cold say first time starting engine then there will not be any bars on temperature gauge until I've driven it for about half hour then it goes up to the 3 bars then will drop to 2 bars when I'm doing about 50 mph if I turn engine off while the temp was at 3 bars then give it say 5 mins then start it again it will be on 3 bars if I leave it a couple of hour the temp will be blank the gauge seems to be reading what it should it's had 2 new temperature sensors in a week

[Paul-R]

Then that sounds like it is reading correctly.

Let's go back to the overheating incident. You were driving along some, slightly hilly at times, country roads. You were doing about 30mph or so and the overheating incident occurred. What exactly happened?

Did the temperature gauge suddenly shoot up to many bars and the STOP light and warning beep come on? Did you then stop the vehicle? If you did stop the car, did the engine sound like it was overheated? -i.e were there slight popping and/or creaking sounds? Could you feel the heat from it while standing in front? Did any coolant escape from the expansion tank?

How long did you wait before restarting and driving away? Did you keep checking the gauge by switching the ignition on and then off whilst waiting? When you eventually drove away what was the gauge reading then?

Hope you can answer those in detail. How long ago was the incident? You may have said already but I've come to this thread a bit late in the day.

[nomis1981]

The overheating happened about 2 weeks ago when the gauge went up to the red and was saying stop engine overheating I pulled over turned it off and opened bonnet there was coolant lacking from the expansion bottle cap I don't remember there being any noises coming from engine as was getting pissed off with car at time but I do remember the fan never kicked in and it was very hot to the touch more then normal I managed to push the car into a field to get off road when I looked again about 45 mins at the temperature it was at 2 bars I stayed there for about an hour before I started car and carried on with my journey it has never happened again since hope this helps

[Paul-R]

You'll have to forgive me as I'm not familiar with the Picasso.

When you say "coolant lacking from the expansion bottle cap" did you take the cap off? Was that very soon after stopping or 45 minutes later? If it was very soon after you stopped did taking the cap off release the pressure? Or, is the bottle transparent enough to see the coolant level inside and you could see that it was low?

Did you top the fluid up either then or later and, if so, how much did you put in? Have you bled the cooling system to make sure there air no air bubbles inside?

Another thought occurs to me. Modern cars are very dependant on the water pump to circulate the coolant and I have heard of an impeller either coming loose or being pressed into the wrong position. I don't suppose that the engine has had its timing belt changed together with water pump?

[nomis1981]

I didn't take cap off the coolant till it had cooled down and added only a small amount back in.
it was leaking from the rim of the expansion tank between the bottle and cap I've replaced the cap now so that's sorted I know they are a high pressure system in these diesels
Ithe coolant has been blead twice since that day as it's just had new coolant put in as one that day it overheated I only had water to hand.
I'm not sure when it last had a timing belt change the last owner said he did it a year ago I've had car for 6 months now but then he did say he changed the powersteering pump but he didn't as it need one of them aswell
I'm gonna look into how much a timing belt kit with water pump is gonna cost me at local garage as not gonna do it myself because these newer cars are a nightmare easier on a classic