What temperature does diesel freeze?

[GreigM]

The reason I ask is it was -15C here last night, and hasn't got above -9C all day, and my diesel Mazda has been stalling and suffering all the symptoms of fuel starvation. It restarts and runs fine then suddenly stutters and stalls, and has nearly a full tank (from a Jet station earlier this week).

Would I be right in thinking some sort of thickening of the diesel could be causing this due to the temperature? And is there an additive or similar I can buy to put in the tank to solve the problem?

[Conor D]

Google seems to think it's around -9.5 degrees C (The gelling point anyway).

Edited by Conor D on Wednesday 8th December 19:58

[thinfourth2]

GreigM said:

Would I be right in thinking some sort of thickening of the diesel could be causing this due to the temperature? And is there an additive or similar I can buy to put in the tank to solve the problem?

Petrol

I think a few litres to a tankful, feck knows how diesels with brains cope with it

[Fordo]

I might be wrong, but i'm sure i've heard stories of people adding a dash of petrol to help thin the diesel out- dont take my word for it though, research throughly before you try

[MondeoMan1981]

I wonder if the additives in the likes of V Power and Ultimate make those diesels less likely to wax?

I'm running with part Tesco and part Shell at the moment and its been ok even with -18 overnight and setting off at -12 this morning !

[anonymous-user]

Shell diesel will freeze at around -11.5 degrees, at least that was the temperature 1hr ago when my diesel E Class gave up half a mile from home and refused to start again.

Additives in it my arse.

ETA I notice you're in Scotland too Greig, I too filled the tank to the brim, made a point of getting Shell rather than supermarket fuel as I thought they'd be prepared and add additives for the cold weather we've been having for well over a week, and it appears to have frozen, gelled, whatever, it'll start and run for about 10 secs before cutting out, not happy.

Edited by anonymous-user on Wednesday 8th December 20:20

[mad4amanda]

I thought that many years ago the fuel companies put an Anti wax additive in the fuel to take it down even lower than the natural gelling point? We used to sell a comma anti wax additive back then to add to fuel. Maybe it is still available?

[KaraK]

Been running my diesel pug around all winter and I must admit its not even occurred to me that this might happen. Not having a temp gauge in the car I'm not sure how cold it has been but from what my housemate's clio was reporting last night we've been hitting -10 easily.

[dvs_dave]

I find it hard to believe that UK diesel is a different brew to that served up in alpine regions and scandinavia where it's MUCH colder all the time?

[Digga]

So if diesel does gel around -10 to -11, what about the oil in the sump?

I bet there are few motorists who even bother to check, let alone act on manufacturer's advice for 'winter' engine oil specs.

[jagracer]

dvs_dave said:

I find it hard to believe that UK diesel is a different brew to that served up in alpine regions and scandinavia where it's MUCH colder all the time?

Less or no anti waxing additive in UK diesel.

[The Riddler]

Digga said:

So if diesel does gel around -10 to -11, what about the oil in the sump?

I bet there are few motorists who even bother to check, let alone act on manufacturer's advice for 'winter' engine oil specs.

http://en.wikipedia.org/wiki/Motor_oil#Grades

Have a read, I tried typing out a reply but it came out as complete garbage.

[Pinky and Perky]

ULSD fuel in the UK is made to specification EN590, there are two different grades coventional and artic grades, conventional Diesel does have a winter grade as well which refineries generally introduce around October time, this is good down to about -12, but you musn't forget this will differ between refineries dependant upon the various surfactants and detergants added back in after the refining process.
Artic grade diesel is not generaly used in the UK. Once the cloud point of the diesel your using has been reached this is sufficient to start clogging (waxing) in your filters and fuel lines.
Try removing your old fuel filter, fill a new one with kerosene and re-fit, please note you should NOT run a modern common rail diesel engine on kerosene alone for very long. Another alternative would be house heating oil. Hope this helps.

[Mr MXT]

"They" run winter spec and summer spec grades. Every terminal will have been running winter spec since end of october ish.

[Ozzie Osmond]

Mr MXT said:

"They" run winter spec and summer spec grades. Every terminal will have been running winter spec since end of october ish.

Quite right. The waxing point is addressed in the fuel blending process and is varied with the seasons.

[GreigM]

Will see how it goes in the morning - supposed to be a lot warmer tomorrow (about 0C) so hopefully back to normal, and have a decent run to do, so will do my run and top off with some diesel optimax and stop using the cheap jet stuff if the forecast is grim again!

[Skodaku]

Cold Filter Plugging Point, CFPP, is a good guide to low-temp performance of ULSD, (Ultra Low Sulphur Diesel, to save someone asking). There are two ULSD grades : Summer and Winter. Summer is supplied mid-March - mid-October and Winter for rest of year.

Temperatures quoted are the HIGHEST at which the fuel should plug a test filter - the fuel may well perform well at a LOWER temperature but must not block above the temp stated.

As I understand it, the numbers are :

Standard : Summer : -5degC. Winter : -15degC

The refiners each work to broadly similar specs but, AFAIK, all the oil majors supply their service stations with ULSD that outperforms the "Standards". The number I've heard for Esso ULSD are :

Summer : -15degC. Winter : -22degC

I think it is fair to assume that Shell, BP, Total et al will give similar numbers.

Anyone having trouble at substantially higher temps has other problems than fuel. Possibly condense in the filter/fuel lines/tank. At -9.5degC it is not ULSD itself choking the system. Google and Wiki are out of date, I'm afraid..............or based on USA input, perhaps - ULSD is a relatively new retail product for The Colonies.

[mosstrooper]

On Tuesday evening my diesel Legacy was starting and running OK at an indicated minus 18. Yesterday morning the max/min thermometer outside the house suggested the temperature had gone down to minus 22. Car thermometer said minus 20.

Needless to say it wouldn't start. Spent most of the day with a hot air gun but no success.

Minus 2 this morning and after a bit of coughing and spluttering we are off and running again.

This is a repeat of what happened in January this year so with a few months of winter remaining I, too, am looking for an additive which will prevent waxing down to about minus 25.

Any suggestions??

[JMGS4]

GreigM said:

The reason I ask is it was -15C here last night, and hasn't got above -9C all day, and my diesel Mazda has been stalling and suffering all the symptoms of fuel starvation. It restarts and runs fine then suddenly stutters and stalls, and has nearly a full tank (from a Jet station earlier this week).

Would I be right in thinking some sort of thickening of the diesel could be causing this due to the temperature? And is there an additive or similar I can buy to put in the tank to solve the problem?

GreigM
you can put 1:50 parts of low octane petrol in it and the sludgingeffect under -10 will be reduced. DO NOT exceed the 1lpetrol to 50l diesel though!!!
Old trick used where winter diesel is not available!

[JMGS4]

dvs_dave said:

I find it hard to believe that UK diesel is a different brew to that served up in alpine regions and scandinavia where it's MUCH colder all the time?

Winter diesel is used all over the Alpine region and Scandinavia. it has additives to ensure that no sludging takes place at lower temps. GB does NOT have this winter diesel!