Hey, I have a problem with my Octavia.

It's hard to start the car if it has been standing for a while after driving. You usually have to crank it two times and in the like first 2 seconds after starting rpm's are too low, engine is almost near cutting out.

Sometimes it happens on coldstart.

Apart from that the car runs fine.

Could it be a temperature sensor, MAF sensor or something else?

Thanks.

Coolant temp sensor would be the most likely cause of the problem. CTS is notorious for failing.

Thanks.

Which one I should get? I heard that they differ in colors.

And could I change it by myself?

New ones are geen, the older ones were black (or brown), iirc. On the TDI is nice and easy to change, and I suspect the same applies to the 20v. It is one clip, remove CTS & old o-ring. Fit new CTS (and o-ring), and retaining clip. Then disconnect the loom from the old CTS and attach to the new one. I find it easier to disconnect the loom afterwards as some the plugs can be a bit fiddly to do.

So the green one should be better?

Online part store offers various sensors from 4 to 17 pounds.

I saw only one in green color.

Green is the modern colour for them, your car probably has a black (/brown) one fitted. Avoid the cheapo ebay ones, they have been known to fail very quickly or be DOA. I got mine from Skoda for about £25, iirc.

Best to get a new o-ring with too.

I found Å koda original sensor costs about 17 pounds. They all come with o-ring.

So to change it, you don't need to drain the cooling system or something?

Have a litre of G12+ handy to top up afterwards, but you'll probably only lose a few cc of coolant if you unpack the new sensor and have it handy so you can plug it in quick once the old one is out.

Oh, well, the coolant needs to be changed anyways.

Another question- if I change the coolant, do I need to flush the cooling system?

Seriously, you could top up the coolant you should lose just swapping the sensor with a shot glass or a vodka glass.

If you think it needs changing anyway, I'd flush the block and radiator too, yes.

Thanks