The cooling system

2005 April, Scirocco got a ‘high temp’ problem. Thermometer always points to the max. I need to park it aside when the engine was heated up. Fortunately, the engine had never over heated.

So, I flush the whole cooling system with flushing chemical, put in new coolant etc. When I put back all the Hose, fill up all coolant & start the engine again.
The cooling fan just don’t move. I have checked all wiring terminals & don’t have any issue.

The engine keeps on heating up, then steam ‘ping ping’ sound comes out from the aux coolant bottle. I know the water had heated up & boiling.

I stopped the engine, removed the thermostat & thermo switch.
(all stock, 87 degree thermostat & 95 degree thermo switch).

suspect that the fan wont move may due to fault of bad thermo switch.
After that, I put on a brand new thermo switch, which is a Germany made 80-85 degree.

I flush the engine again, put in new coolant & start the engine. The fan starts to run after warm-up. but after a while, it stopped & the engine keeping heated up & boiling. WTF.

I have touch the radiator, I feel that the area near thermo switch was cool, But the water hose are super hot!
Then I suspect that it was a clog in radiator.

After consulted with SuiteR, I think that the clog may due to the steam traped in radiator.

I take off all the hoses of the radiator, drained the coolant, touch the inside tubings. I feel that the tubes inside radiator are still thick & strong…..

finally……. i have found the tiny outlet on the top of radiator was got jammed. The steam in radiator got trapped.
see the picture. Then I clear up the the outlet hole with a small paper clip. & then put the small hose back on. and fill up coolant.

guess what, all overheat problem all gone……..
rocco is running cool now!!!!

PICT0156.JPG😀 😀

The removed stock thermostat & thermo switch.


The system was then flushed & refilled by the Blue Mercedes Benz Coolant.

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