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Diesel gelling
PSpirine - 21/12/10 at 05:06 PM

I don't currently have a diesel, but was wondering - what temperature is UK diesel good down to?

Anybody had issues?

BigLee - 21/12/10 at 05:13 PM

It starts to gel at -9.5 degrees C apparently. But depends on the particular blend. It's bio fuels that'll have the real issues as that starts to thicken up alot sooner putting stress on the high pressure pumps. Mine just takes a few seconds longer for the glow plugs to hit the right temperature, then a couple more cranks to fully fire up. I don't get any choice in the matter as it's a 'start' button.

matt_gsxr - 21/12/10 at 05:23 PM

I had problems starting my A6 (2.0Tdi) yesterday and think it was from exactly this problem.

Fresh tank on Saturday (BP station), temperature gauge was reading -10.5 deg C at 9am, I was told it was down to -15 deg C in the night.

Very unhappy starting and ran rough for a minute or so.

mangogrooveworkshop - 21/12/10 at 05:26 PM

Theres a winter blend for fuel in the uk.

However back in 78 Dad had the cortina mk 3 and petrol froze in the fuel pump.......and carb.

However we lived on top of a hill with fields all round....stone cottage and a single coal fire ......foook that was cold

PSpirine - 21/12/10 at 05:27 PM

I wouldn't have thought even the winter blends around here would have anticipated anything below -15!

Do new diesel cars still recommend diluting with unleaded in these temperatures in the user manuals?

T66 - 21/12/10 at 05:37 PM

quote:
Originally posted by PSpirine
I wouldn't have thought even the winter blends around here would have anticipated anything below -15!

Do new diesel cars still recommend diluting with unleaded in these temperatures in the user manuals?





Ive not heard of diluting diesel with petrol, please enlighten me ?

bigbravedave - 21/12/10 at 05:38 PM

Interesting one this, as part of my job we do cold start testing on constuction equipment.

Basically the fuel suppliers in a majority of europe start adding anti-waxing agents into the BS EN590 (and other standards of) diesel before winter, mainly to prevent themselves having waxing issues before it reaches the pump, as alot of it is stored in some pretty cold places if its come from the north.

Throughout the summer they can get away without it as we once famously discovered doing -25 degree cold start testing in July.

The only problem is when you buy diesel in summer and use it into winter. As its bloody expensive to drop a climate chamber big enough to accomodate construction equipment to -25 oC we buy drums of BS EN590 "winter diesel" to ensure no problems on test and fortunately it ain't red and you don't need much to do a cold start test if you know what I mean ;-)

mccsp - 21/12/10 at 05:58 PM

I work for a diesel engine manufacturer and we specify a change to winter diesel and low viscosity oils at
-18degC.

PAUL FISHER - 21/12/10 at 06:00 PM

quote:
Originally posted by T66
quote:
Originally posted by PSpirine
I wouldn't have thought even the winter blends around here would have anticipated anything below -15!

Do new diesel cars still recommend diluting with unleaded in these temperatures in the user manuals?





Ive not heard of diluting diesel with petrol, please enlighten me ?



Back in 1982 when I was then working as a HGV technician, it was a very cold winter, we had vehicles waxing up all over, one of the cures was to put a fire under the fuel tank for a while, then after removing the fire, add a gallon of petrol to the tank, that always did the trick, and got them running again, you find farmers often use the same method for there tractors, but I would not add petrol to a modern diesel engine .

BigLee - 21/12/10 at 06:41 PM

quote:
Originally posted by T66
quote:
Originally posted by PSpirine
I wouldn't have thought even the winter blends around here would have anticipated anything below -15!

Do new diesel cars still recommend diluting with unleaded in these temperatures in the user manuals?





Ive not heard of diluting diesel with petrol, please enlighten me ?


I think this is an old one. Although it could work at preventing it waxing, it does remove some of the lubricating properties of the diesel, which can cause premature wear on modern fuel pumps.

andrew - 21/12/10 at 07:30 PM

i put a drop of kero in the tractors stops them waxing as we are still on summer fuel ,

PSpirine - 21/12/10 at 08:01 PM

My BMW manual from around 1990 (again mine was a petrol, but it had details about diesel models) suggested adding up to 10-15% unleaded during the cold.

It does reduce the lubricating properties, but not by a lot if you're only adding 10% - this was certainly acceptable on all the old indirect diesels. Plus it greatly reduces the strain on the injection pump.

I take it this isn't common practice on modern common rails though...


Anyone got a post-2003 diesel car they can read through the manual and see what it says?

matt_gsxr - 21/12/10 at 09:16 PM

quote:
Originally posted by PSpirine

Anyone got a post-2003 diesel car they can read through the manual and see what it says?


I'll read the manual when it doesn't start, like everyone else!

Matt

dilley - 21/12/10 at 10:21 PM

A drop of petrol doesn't hurt, as for lubrication....modern diesel is crap!! it used to be like treacle! on a modern pump adding a drop of engine oil at every fill up saves pumps! tried and tested on 30 modern transits, no more new pumps!

stevebubs - 22/12/10 at 12:02 AM

quote:
Originally posted by BigLee
It starts to gel at -9.5 degrees C apparently. But depends on the particular blend. It's bio fuels that'll have the real issues as that starts to thicken up alot sooner putting stress on the high pressure pumps. Mine just takes a few seconds longer for the glow plugs to hit the right temperature, then a couple more cranks to fully fire up. I don't get any choice in the matter as it's a 'start' button.


My 08 plate Mondeo FFV came with a kettle lead that you plugged into the lower front grill if it dropped below -15C...

Ninehigh - 22/12/10 at 01:26 AM

Couple of nights ago my mondeo registered -10 and no problems really. Need an extra 2 seconds to start and it ran a little rough for a minute but I wasn't exactly ready to drive away immediately anyway

tony-devon - 22/12/10 at 09:49 AM

came out to minus 11.5 this morning

the glow plug light on my 2000 golf tdi took longer to go out, it started and ran a bit lumpy for a couple of minutes, but drove fine when I went back to it 5 mins later

dhutch - 22/12/10 at 01:52 PM

I understand from those at work that shell standard winter diesal is rated down to -15. But i dont know if thats correct or not. If it is, its a bit close for comfort, but that wouldnt supprised me.

I have a petrol and its started onthe button every day so far...


Daniel