Polo overheats despite change of thermostat
Most likely the waterpump impeller has came loose from the shaft. When it spins slow it grabs onto the shaft. When it turns fast the impeller slips on the shaft.
First thing to do is once is gets hot, after ripping around the block. Get out and pop your hood. Check to see if coolant is flowing back to the coolant bottle from the little hose connected to the side of it. It not then let it cool down and...
Under the intake on the passenger side is the thermostat housing. Two 10 mm bolts hold it onto the block. If your next to the alternator, your in the right spot. Take those out and pull out the thermostat. Stick your finger in the hole and to the left and feel the waterpump. You shouldn't be able to move the waterpump impeller. If you can spin it with you finger, then it's bad.
Polo overheats despite change of thermostat
Thermostat is not opening. BECAUSE the way you refilled the coolant was wrong. You have air on one side of the thermostat(and air never gets hot enough) to open the thermostat...so you overheat.
To correct. Let it cool. Pull off lower rad hose and drain block and rad of coolant(again) Now put on lower rad hose to rad and the thermostat housing to the block. Pull off top rad hose and pour coolant down the hose pipe into the motor and fill it up. When full, reconnect rad hose to top of rad. Now fill the rad and the overflow container. Now coolant is on %26quot;both%26quot; sides of the closed thermostat.(no air pocket). Car should work fine.//Note: this will also be the reason why the fan was not coming on either,,,because fluid was not flowing past the temperature sensor for the fan.
The Most Likely reason
This could be bad news. It could be a blown head gasket. I had one on a Datsun pickup truck. The engine heated up very quickly. I repaired it myself. When I removed the head I had expected the head gasket blown to bits and pieces, but all I could find was a tear from one of the head bolts toward the cylinder. I guess because of the pressure in the system the water quickly ran into the cylinder.
So one test to make to prove that the head gasket is blown is to take out the spark plugs and then crank the engine to see of any water is coming out of any of the spark plug openings.
Please, don't assume that I am correct with this, don't take off the head until you have evidence that what I suggest is indeed true. LOL
is the coolant system a pressurized system? if it is and you have opened it it will continue to overheat until you bleed the system
