VW Vortex - Volkswagen Forum banner

Cooling system Q

1K views 9 replies 5 participants last post by  vwabbitman 
#1 · (Edited)
I have this 80 Rabbit 1.7 gasser. The other day the fan decided not to kick on and I heated up real quick and was almost bad... anyway..

I've tested the fan and it's good. I have tested the circuit from the thermo rad switch plug by jumping the plug and the fan comes on, indicating that the circuit is good. I just don't understand why the rad switch would be bad. It has less than 5k miles.

So tonight I am planning to replace the thermo rad switch, got a new one today.

Do these really go bad like that? Also only water was ran in the car no coolant. I know I need to get some coolant in it before it freezes.

Could the water pump have gone bad causing the car to get hot fast but not the coolant/water thus causing the switch not to make the fan come on?

Thanks
 
#2 · (Edited)
Jumping the thermo switch by arcing the 2 external post is just bypassing the thermo switch not testing it to see if it's good.

& yes they go bad like that.

Most likely NOT the water pump. Now the thermostat might be bad & they all have different opening temps. You can test that by sticking it into a boiling pop of water & see if it opens at the temp they water says. Thermostat opening temp is marked on them
 
#5 ·
they get stuck open
and
they get stuck closed

hell just cleaning it and banging on it sometimes fixes it
but i wouldnt trust it


one time mine got stuck closed and the fan ran continuously...i barely caught it
 
#6 · (Edited)
...Do these really go bad like that? Also only water was ran in the car no coolant. ...
When you run JUST water in your system, it can do massive damage quickly. Why? The coolant does much more than prevent freezing. It prevents electrolysis in the system. Basically your cooling system acts like a battery. The aluminum reacts with the water, the brass, etc. It eats these things away.

I have seen some WEIRD failures because of just water only. Parts wear out much quicker. And if your grounds are less than perfect, this happens even faster. Putting anti-freeze in there helps control this and prevent the electrolysis.

In fact, I ran my system like this once during middle of summer. I had to replace a thermostat and thermos switch, and didn't have any coolant kicking about so I ran just water. I was all "It will be okay tell next oil change..." In under 3k it had eaten both the new thermostat and thermotime switch failed again, and the system had to be flushed it was so fugly.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top