HELP overheating problems

[raysy]

Ok all I can race through gears at high speed and gauge stays at half way so that's ok.
However on the motorway put my foot down in 5th and pulls lovely but once it touches about 80 I get the warning temp light come on and the gauge is of the scale. Take my foot of the accelerator and gauge drops immediately back to half way and warning light goes out. So any ideas peeps. Only happens at speeds over 80 and yes before I get well don't go that speed it doesn't solve the problem.

Thanks in advance
raysy

[SD1too]

Ok all I can race through gears at high speed and gauge stays at half way so that's ok.
Not necessarily Ray. :D The gauge will stay at 'half way' even when the temperature rises as high as 114°C which is definitely not OK. ;)

The first things to do are to check the coolant level in the expansion tank and do the 'demist test' to test your radiator cooling fan.

Simon

[raysy]

Thanks Simon will check now

[raysy]

Ok Simon have done the demist test and fan comes on ok

[SD1too]

What about the coolant level?

If that's up to the 'max' marker, then activate the instrument pack diagnostics (guide is here (http://www.the75andztclub.co.uk/forum/showthread.php?t=185808)) and monitor the actual coolant temperature from starting the car from cold to driving it just around your neighbourhood. It should remain in the low to mid nineties, with occasional excursions to 100° when stationary in traffic.

Please report back with the results.

Simon

[raysy]

Thanks Simon I will report back to you at some point cant seem to get the you tube post at the mo.

Cheers

[SD1too]

Here's the written word version (http://www.the75andztclub.co.uk/forum/showthread.php?t=85855&highlight=diagnostic+mode+update) if it helps.

Simon

[raysy]

Hi Simon in diagnostic mode driving round the block temp was between 75 and 78 is this ok???

[SD1too]

Ray, your profile says that you have a V6. Is that correct? The temperatures you've given are more likely for a diesel.

Didn't the temperature rise any higher than 78°C? For how long did you drive it?

What happened before the occasional overheating started? Was the car in a garage for some work to be done? Have you done any work on it?

Simon

[raysy]

Ray, your profile says that you have a V6. Is that correct? The temperatures you've given are more likely for a diesel.

Didn't the temperature rise any higher than 78°C? For how long did you drive it?

What happened before the occasional overheating started? Was the car in a garage for some work to be done? Have you done any work on it?

Simon

Hi yes a 190 2.5 v6.
drove for about 5 to 10 mins

only happened once before again on the motorway but my clutch was slip and I didn't realise as music up load and window down, car was rev up when I put my foot down so I assumed as the clutch was slipping and it was just rev up that was the cause of overheating

now had a new clutch fitted a week ago seems to only come on when I am nearly at 90 on m/w

[SD1too]

Well Ray, I'm struggling to explain the contradiction with what's apparently happening with your car.

A 78°C running temperature means that the thermostat is open too soon. This will not lead to overheating if your fan is working, and you say it is. So the red overheating LED when travelling at high cruising speed is odd. Your evidence that the gauge pointer immediately drops to normal when you decelerate suggests that:

The engine isn't overheating; it's a sensor fault
You have air in the cooling system due to a leak or a faulty expansion tank cap. These would cause coolant loss. I've asked you about this (twice) but I haven't received your reply. :o


It does seem unlikely that you have more than one fault, but anything's possible I suppose.

Simon

[raysy]

Sorry Simon I took the expansion tank cap of and a lot of air came out.
level was in between min and max so no loss. Thanks so much for bearing with me Simon new to Rovers so you patience is appreciated :D

[T-Cut]

I took the expansion tank cap of and a lot of air came out.

Was that when everything was stone cold or shortly after driving?

TC

[raysy]

Hi T-Cut was after I took it out for a 5 min drive so that's why the air came out :duh:

[T-Cut]

Opening up the header tank shortly after driving doesn't tell you much. It's far more informative to check the cold coolant level before a reasonably long drive (10 miles or more) - maybe repeating your overheat routine - then allow the engine to cool down completely (preferably overnight). Only then remove the pressure cap. Note any release of pressure and the coolant level.

If you run the trip screen diagnostics for coolant temperature while you repeat the overheat routine, you will confirm that the red light does indeed equate to a temperature of 125-130C. If that's the result, there's clearly an issue.

TC