This morning I've seen a wet zone under the front bumper...I checked the fluids (oil and coolant) .. they looked fine and I got to work. After the car has set about one hour, I've seen something dripping from under the battery compartment ( I can't tell for sure from where, I have a steel engine shield under the car). I've checked again the coolant level, it was between max and min, so was ok. How can I tell if it's coolant or power steering liquid ? I guess that do have about the same color.

Check for wetness or dried coolant stains around the radiator thermoswitch. Seems a common leak point.

I've checked the engine bay and there were no visible leaks. 

Could it be screen wash fluid?

Nope, that was my first thought. The screen wash fluid is blue. What's dripping is kind of sticky. My nose meter doesn't help much to identify what kind of liquid it is. I've lost about ~300ml over night and about 150ml this morning. If it would be steering fluid, it should start to fail soon as it has ~0.8litre.

 

Later edit: there were no signs while driving the car. I couldn't tell from behind the wheel if something went wrong. Everything worked as good as always. I've been in heavy traffic on my way to work, the engine wasn't overheating, the steering was ok, not harder of anything than usual.

Later later edit: last night I've floored it for a couple of minutes (like changing gears near to 4500-5000rpm, upto 85 in 4th), but didn't hit the rev limiter. I didn't hit anything though, so a crack in the radiator it should be out of the question. Since it wasn't leaking from under the engine, a crack in the engine block should be eliminated as well.

 

Wino, that thermoswitch, would it be the in same location for 1.4 mpi as it is for the 1.2 ? I have two radiator fans though. When I got home last night, the fans were working, so the switch should've been doing his job.

 

Edited 13 November, 201510 yr by Alexandru

Yep, you've found it. It will still work while leaking, it leaks around the thread where it screws in, there isn't any seal other than pressure of the metal switch flange against the plastic radiator end-moulding.

 

Fixed coolant leaks from both Polo and Fabia this summer by re-tightening the thermoswitch a little.

 

But the quantity of leakage you're reporting would surely show in the expansion tank?

Edited 13 November, 201510 yr by Wino

Yea...it's strange. I filled the expansion tank a few days ago (with a cold engine) between max and min, and after that (to be read, after 20 to 50 miles driven, with a cold engine, again) it was a bit over max, like 2cm..something. It's not such a very sure meter I guess. It might depend on how close is the Moon, with high and low tides. But that's another story  .

Edited 13 November, 201510 yr by Alexandru

It seems it's the lower part of the thermostat housing. I've just got a call from my mechanic. So it's not the thermostat housing, it's the part where it is getting on. I'm now trying to identify it. Would 047121111S be a fix ?

Edited 13 November, 201510 yr by Alexandru

Actually there should be a crush washer on the temperature sensor, mine leaked until I bought a new sensor and it came with a crush washer

I knew about my thermostat housing leak for about an year, but it wasn't leaking that bad. It seems that it's leaking only when the engine is cooling. Interesting stuff, huh? 

It seems it's the lower part of the thermostat housing. I've just got a call from my mechanic. So it's not the thermostat housing, it's the part where it is getting on. I'm now trying to identify it. Would 047121111S be a fix ?

I believe that is the right part number for the overall housing/thermostat/temperature sensor, yes.  Comes with O-rings for mounting against engine head and for temperature sensor which will be already mounted.

I've ordered the part, it' £30 and I'll have it here in less than an hour. For some reasons, OEM Skoda is 50% compaired with OEM VW (same part number). I don't get it...maybe I don't have to.