Cooling fan
 

The radiator cooling fan on my 2005 75 Connoisseur (K series engine) comes on far too frequently. It even starts 30 seconds after starting up from cold. There is no water shortage problem. It's difficult to tell if it's on when running but when stationary it will always come on - and is it noisy??? Yes. does anyone have any ideas as to the root cause of the problem?

Do you run the aircon/climate control all the time?

TC

Cooling fan
 

Hi TC - thanks for reply. No I only use the air con on odd occasions. Ever since I bought the car a year ago I've had the problem - autumn, winter, spring. Any ideas?
Cheers
Martin

I would start by checking the wiring and sensors

Martin,

Activate the instrument pack diagnostics like this and report back with your coolant temperature as you drive the car. Ensure that your air con. control panel is in 'Econ' mode throughout.

Simon

You've confirmed the cooling system is watertight, so I'd suggest it could be the apty named Double Thermostat Jeopardy. Do you know if there was any head work done before you bought it?

TC

- thanks for that - it makes sense, but Simon has shown me how to activate the test system on the dashboard (had no idea this existed!!) and another member has mentioned double thermostat jeopardy which I'm about to check out. I'm very grateful to all members who've made suggestions. Thanks everyone. Martin

Hi TC - yes, the head had been skimmed a month before I bought the car. What on earth is double thermostat jeopardy? Thanks. Martin

It's when a late 1.8 engine gets some head work at a garage unfamiliar with the PRT system fitted to them. The Pressure Relief Thermostat is situated in the coolant hoses near the bottom of the radiator and was introduced by MGR at a late stage in the car's development. It reduces the thermal stresses on the head and was intended to reduce the frequency of HGF. Clearly, it was only partially successful. The upper/head housing, where earlier engines have a conventional thermostat, is empty. That is until the garage fits a new stat as part of the head gasket fix. What you have then is DTJ. Engines in this situation heat up very rapidly indeed. Some simply run over hot all the time. Others are so hot, they become undrivable. I'll bet my boots you have DTJ.

More on the trip screen diagnostic mode: http://www.the75andztclub.co.uk/foru...ad.php?t=55585

TC