Volkswagen: Overheating, water coolant, vw polo

Question
Hi Ron,

I am new to this site but it is great help. I have already told all my friends and colleagues about  this site.
I have a VW Polo CL 1994. Few weeks ago although my internal heater was and still is working but it stopped blowing out hot air all together. I have not done anything about it thinking I do not need it any way. Now the engine started overheating. After 3-4 miles temp needle goes up to 110 degrees and on to red. Are both problems related? Please advise what should I do now?

Answer
Hi Dariush,

They are most likely related.  The heater gets warm by your water pump pushing coolant through a heater core in your Polo.  A fan blows over the heater core and makes the interior comfortable.  The temperature knob on your dash controls how much hot water/coolant flows through the heater core.  

Thats how cars are heated.


Coolant is also in your radiator, which is also pumped around the engine, to pull heat away from, so doesn't get too hot.

Based on your very clear symptoms,  here is a fair guess:

1) No heat when the engine is at operating temperature usually means no coolant in the heater core.

2) Engine temperature getting too high after 3-4 miles can mean no coolant in the radiator.

Thus, safe bet, is either:

a) All of your coolant leaked out, refill it and check for leaks.  Broken hoses or a leaky radiator could cause this.

b) If you are sure your Polo is filled to the top with coolant, the thermostat or the water pump are at fault,  not likely though, given your symptoms.

Well you are fortunate that these sytems are fairly simple, so this data should help track down your problem.

Lots of Luck and be safe. (don't open up the radiator when the engine is hot, you can be burned by steam)

Let me know how you make out!

Cheers,

Ron