Sorry, Losha, but none of that makes any sense. If the fuel is not adequately winterized, having a full tank of it will not make any difference. If your battery is strong and your starter is working okay, but the fuel is gelled, then you're not going anywhere. If the fuel in the filter is gelled, it will never reach the injectors, no matter if the filter is new or not.
I'm sorry I should wrote bit more clearly and shared my experience with owning TDI since 2005 and only had 2 times that I had fuel gelled up in my Golf and it was twice exact same mistake I made that caused gelling issue, other then that I hardly ever use any additives in winter and don't have frostheater to plug in to keep engine warm, and my TDI always started in below zere temps no problem.
Socks, made very valid explanation point on why what I said above make sense. When your fuel level is low light is on you have about 2 gallons of fuel left, engine is warm, fuel returning back to tank is warm, outside air temp is near 0 degrees, what is going to happen inside of tank with those 2 gallons of fuel left???? it going to gel up very quickly do to low quantity of fuel to first of all dilute that moisture cause from returned hot fuel and cold air in tank, second reason as been mentioned already small quantity of fuel will freeze quicker then a larger amount.
This is why you want larger amount of fuel in tank to A: absorb & dilute any moisture build up in fuel system, B: larger mass can hold stable temp at longer periods of time then very small tiny portion.
If you would like to, you can try experiment with this on your Golf, but be prepared to call tow truck or have ability to get car to some warm place to park it after fuel gells up and as well have new fresh fuel filter on hand.
