My Grand Voyager 2.8 CRD(2006) has just developoed a fault in so much as the temp gauge which has always run at about 1/4 up the scale is running at 1/2 to 3/4 up the scale and yoyo's up and down depending on how hard the engine is working. Fluid levels at correct level and no leaks. Could this be thermostat on it's way out. Any help or suggestions greatfully recieved.

 

temp gauge at 1/4 would suggest a stuck open thermostat. Temp gauge a 1/2 is normal. Temp gauge at 3/4 is a problem.

The thermostats are know to stick open, but I've not heard of them sticking shut. When you say the engine working hard is that when uphill at motorway speeds?. I'd suggest checking that the airflow is OK through the radiator - often they can end up clogged with debris and leaves etc.

Regards
Richard

 

Thanks Richard

air-flow through rad checked.

On hills the gauge goes up, once on the flat goes down again. Motorways not as bad, cruise control helps with that one.

Many thanks

 

My GV had these identical symptoms --
1) Coolant was old and hadn't been changed in years, which led to ---
2) Blocked ally radiator by corrosion caused by neglect of above, which led to ---
3) Stuck open thermostat, which they are designed to do when overheating is present.

Quod erat desperandum.

Leedsman.

 

As Leedsman says blocked rad could be a cause.

I would suggest the next step should be testing the thermostat in a pan of hot water - but they are a bugger to get to and get out - given the effort of removing one you may be better off replacing it as you wont want to do it twice.

A flush out of the cooling system wont do any harm either and it could probably do with a fresh load of anti-freeze.

Regards
Richard

 

Thanks Guys

Looks like I am getting the toolbox out over the xmas break!!