My Car Won't Start

[Natjen13]

When car wouldn't start, when seen too he told us it's out of diesel which was untrue as we put diesel in and no light to indicate this but when left too fix it he told us he had too drain the diesel before putting more in, this confused me as he told us it was empty.

[EDDIE51]

If you let a diesel run out of fuel you risk getting the sludge and water from the bottom of the tank in the engine. You should drain the remaining dregs of fuel out before you refill it.

[davegosling]

^^ Yes, absolutely. As a general rule, you should try not to let the fuel tank drop below a quarter full.

[Tilly2]

Does that apply to petrol as well, Dave?

[Natjen13]

That's OK but there was diesel in as I put it in 1day ago and only had the car since that day and only did 6mile Max

[EDDIE51]

Petrol is not as much of a problem, it can happen but not likely.
Diesel often has some water in it and it forms sludge in the bottom of the tank.

[EcclesCake]

Is that still the case with modern diesel formulations? I thought things had moved on with more advanced filters and formulations.

[bhg481]

It doesn't seem to ocur to people that fuel is ALWAYS taken from the bottom of the tank, no matter how much is in there. When the vehicle is moving around the fuel in the tank mixes, so I can see no reason why running the fuel low should pick up crud. Certainly, in the case of older diesels, if you ran the tank dry it was necessary to blled the system but that's done automatically in modern diesels.

[Tilly2]

I always leave my car without filling up until the onboard computer pleads with me to do so. :-) Then I only put £10.00 worth of petrol in.

[EDDIE51]

The fuel is not taken from the very bottom of the tank. There is a 'sump' about an inch below the fuel outlet. If you run completely dry the new fuel can stir up the sludge when you put it in. All diesel has a detergent additive that is intended to keep the water in suspension. Diesel is a lot closer in density to water than petrol is and it mixes more easily and forms an emulsion. I used to test diesel fuel for water every day, it is an ongoing problem.

[EcclesCake]

I have an irrational loathing of visiting the fuel station I know full well to minimise my hatred I would go for significantly more than £10 worth.

[jno]

if you put diesel in yesterday then either it's got a massive leak or the guy has misread it.

This is a separate matter from needing to drain a nearly empty tank, though.

[Tilly2]

£10.00 worth sees me through the week.

[EcclesCake]

You used to Eddie, care to be more specific? Things have moved on a fair bit, have you and your thinking.

[EDDIE51]

I used to work for an oil company. We tested diesel fuel for water every day as well as flash point and 'wax point' It is still done now. The wax point is the temperature that diesel fuel becomes wax like and will not flow. There are still today 2 types of diesel fuel, winter diesel and summer diesel. Winter diesel has a lower wax point than summer diesel. The fuel companies still switch from winter to summer diesel and back every year.
There was a problem with Tesco diesel containing water a few months back , they ended up having to pay to have a lot of fuel systems flushed and cleaned.

[EDDIE51]

Winter and summer diesel explained here
https://en.wikipedia.org/wiki/Winter_diesel_fuel

[EDDIE51]

Uk winter and summer diesel details here along with the change over date, there is a winter diesel changeover date just as there is a clock change date
https://en.wikipedia.org/wiki/Winter_diesel_fuel#United_Kingdom

[EcclesCake]

Eddie I suppose i could accept your argument or I could listen to my husband who has in excess of thirty years professional experience and proven qualifications.

Tough call.

[EDDIE51]

Before you ask they do not sell winter diesel all year as the extra anti wax additives mean it costs more to produce.

[Hopkirk]

Considering the state of some roads I find it hard to believe there is crud at the bottom of the tank. Perhaps in this case the fuel filter is blocked.