Hi everyone,

This is my first post on this forum. My old '94 Magna (275k kilometres) has started overheating. I put in a brand new radiator 6 months ago and replaced all hoses etc so I think that part is O.K. The coolant has overflowed from the coolant reservoir. This seemed to happen just as the car stopped and the engine switched off. It also looks as though the cap on the reservoir has cracked or warped.

I guess this is likely to be a thermostat problem. Where exactly is the thermostat on this model and how can I test it?. Any help greatly appreciated.

Regards
Art

Follow the top hose of the radiator to the engine, undo the bolts and pull off the pipe - there will be your thermostat.

Easiest way to check is to take it out and pop it in some boiling water, see if it opens.

You can also test by bringing the car up to operating temperature and touching the top and bottom hoses simultaneously, if the bottom is cold, thermostat is your problem.

Turn the heater on full blast to minimise any damage while it is overheating and avoid driving in this state or you'll end up with even bigger issues!

are the cooling fans kicking in

Hi everyone,

This is my first post on this forum. My old '94 Magna (275k kilometres) has started overheating. I put in a brand new radiator 6 months ago and replaced all hoses etc so I think that part is O.K. The coolant has overflowed from the coolant reservoir. This seemed to happen just as the car stopped and the engine switched off. It also looks as though the cap on the reservoir has cracked or warped.

I guess this is likely to be a thermostat problem. Where exactly is the thermostat on this model and how can I test it?. Any help greatly appreciated.

Regards
Art

Can you take a picture? I'm quite sure I know what is happening here, when your car warms up, the coolant in the engine/radiator expands. This means some of the coolant has to be displaced into the coolant overflow. However if the cap on the overflow bottle is cactus/cracked, it'll pour into the engine bay rather than coolant bottle. This will give symptoms like overheating, because you'll end up rather low on coolant. Solution; Repco or Autobahn sell bars leaks replacement universal overflow bottles, they're extra large, hold about 2.5 litres.

If it is not the above, it may be your thermostat. But, do you actually notice it overheating when you drive? As in temp gauge going into the red? Remember this temperature is read from the coolant temp sensor in the cylinder head. If this doesn't go into the red, it's likely not actually overheating.