Hi
The fuel available locally is the main concern..that's why I asked what region. Over here Rompetrol use additives which, in theory, would work at the temperatures you quote. Our builder has seen the Rompetrol trucks coming from the same depot in Varna as all the other makes, but every petrol supplier will add their own additives...Rompetrol definitely say their Winter diesel is viable to quite low temperatures. This year I have found a supplier of Castrol additives, which quote viability of the fuel down to quite low temperatures. We probably can get the "real deal" Rompetrol in North Central Bulgaria, as it's close to the Romanian border, and 2 years ago , I'd drive to the local Rompetrol station , and it was yards better than the rest....last year, they didn't quote the day from which they put the additive in , so I stayed in. Last year, we hit minus 30, and the diesel taxis were still running...our usual habit is to get a taxi if we haven't got a clue whether the fuel is up to the task. SO...how do the taxis run at that temp?....The usual chap swears that he adds a good measure of urine to a tankful????!!!!
...however...the amount of rakiya consumed by the average Bulg during a lifetime probably adds the secret ingredient to the "additive"
Starting at minus 27 will be solely a fuel problem, as a pre-heater wont do anything for you...Normally, I find that if the temperature has been below minus 10 at night, normal diesel will cloud , and you'll not start until it has been over minus 6 for a few hours. Cloud point can be anywhere between plus 4 and minus 18 C...also, running will be affected by the amount of water in the diesel. My thoughts, from past experience, is that the position of the Bongo fuel tank is perfect for chilling. The underbody tray collects airflow, and concentrates it into a flat stream that nicely cools the bottom of fuel tank only a few feet from the rear end of it!....so, without deflecting the airflow away, you have to add wind chill from the forward motion. Three years or so back, I was travelling along nicely in the Bongo, and it started to cough and stall out...but I managed to keep it running, and it picked up...Oh doo-doo EXPENSE, I thought, but returning home an hour or so later, the temperature had risen 10 or 15 degrees, and the Bongo was running sweetly. At the time I felt it starting to fail, I prayed the problem was fuel!...the particular area is a dip in the road, always cold, misty and spectral in appearance...SO...it's cold, forward motion, air quality, and density that affects your running.
Without quality additives, you'll need to ensure warmer air at the intake, heated fuel filter, tank and fuel line heaters...an engine pre-heater won't do a thing for you!...except, maybe to enable you to be warm in the car....I use a good winter coat
I'll be testing with a vengeance this year, as I have purchased another diesel car, and a 6.5 KW diesel generator, so they'll have to start!...From next week, I'll start using additive , and filling the tanks...results after winter!...your best bet is a quality additive.....I've bought Castrol
Cheers
Helen