C250 turbo diesel doesnt start in cold weather

[charliefarlie]

I have a troublesome C250 diesel 1998 , it starts first turn and imeadiatly stops within 3seconds will not go again this only happens when we have very low tempratures and the car has been sitting over night out side , the temp was minus 7 , it happened before when we had minus 6/8 i tested the glow plugs and replaced the fuel filter also was told on here to check the little filter that sits to the side of the main filter which i did it was full of muck so cleaned it all put it back in and tried starting the car it eventually started no prob and hasnt been a problem till now yesterday it fired up then imeadiately stopped would not start again , left it till later in the afternoon evening after preheat it reluctantly fired and now starts no problem at all checked the little gauze filter it is as clean as a whistle ,am pretty sure its not glow plugs and not filter , pump seems fine, some one did say their is a gauze filter near or in the fuel tank but cant see how i can easily get at it its an estate by the way .
Any suggestions would be greatly appreciated .

 

[panason1c]

Could it be the fuel waxing at those low temps?

During the cold weather, adding a drop of petrol to the fuel wouldnt hurt, used to do it with my old diesel Audi many years ago, it even said in the audi handbook what percentage of gasoline to add during freezing weather.

 

[jay1983]

Check for air in your fuel lines. Quite common in the diesel engines and seems to materialise in cold weather.
Could be down to brittle pipes or perished o-rings

 

[spike60]

Could it be the fuel waxing at those low temps?

During the cold weather, adding a drop of petrol to the fuel wouldnt hurt, used to do it with my old diesel Audi many years ago, it even said in the audi handbook what percentage of gasoline to add during freezing weather.

In 30 odd years as a diesel tech I've only seen waxing a couple of times and that was on the back of the Pennines, I would not think temp anywhere near waxing this winter. I didn't see any last year when got a lot parky! I think fuel has additives to delay the onset these days. It also stopped engines that were already running, it usually clogs the filters on the ones I've seen.

 

[panason1c]

It wouldnt hurt, in this case, to add a drop of petrol to the diesel even if only to eliminate the possibility of waxing.

 

[renault12ts]

It wouldnt hurt, in this case, to add a drop of petrol to the diesel even if only to eliminate the possibility of waxing.

It's air in the fuel lines as already suggested. The classic sign is the starting then stopping almost immediately.

No where is cold enough anywhere in the UK this winter to cause any problems with fuel.

 

[SilverSaloon]

when it does start do you see any bubbles in the clear fuel lines around the filter area?

if so you likely need new orings on the seals.

try these:

mercedes oring fuel viton kit | eBay

 

[panason1c]

It's air in the fuel lines as already suggested. The classic sign is the starting then stopping almost immediately.

Or.........it could be momentarily firing up on the fuel already within the pump/injectors and then stopping due to not drawing more fuel due to waxing.

 

[SilverSaloon]

its not going to be waxing.... i'm on 100% waste veg oil in mine at the moment and it still starts fine. it will be the common issue of air in the fuel lines causing a drain back to tank. so the fuel in the fuel filter is there to start the car, then it cuts out as there is a big gap of air in the fuel line. then after a little cranking it brings the fuel back up to the filters & IP and the car starts as normal.

park the car nose-down on a hill and you'll find it wont have any issues. park it on a flat or uphill and you have the issues.

 

[mct_cars]

Needs to get to less than -10C for plain old Diesel to start waxing, and be consistantly below that temp for a long time, although as said above Diesel with additives is likely to be a lot lower again. It got to -20C last year and I had no problems with waxing.

 

[charliefarlie]

Hello & thanks for suggestions & thoughts re none starting in cold weather yes its been cold here since last week minus 5 most days and 7 the other day since then its milder again the car starts fine now no problem , havent seen air bubles in pipes at all , shall try parking down hill when frosts return or may well just shift me trikes and put the bugger it in the garage .

 

[panason1c]

It could be air in the system but i believe in keeping all options open, bear in mind that the OP could still have summer diesel (no anti waxing additive) in the fuel tank, and purchased from a petrol station that has not had a winter diesel delivery due to low sales turnover , ie..rural garages. (i used to work for Esso at Avonmouth a few years ago)

 

[Dieselman]

Or.........it could be momentarily firing up on the fuel already within the pump/injectors and then stopping due to not drawing more fuel due to waxing.

It's not waxing...

It's not likely to be water freezing either in the temperatures we are having, it will be air being drawn into the fuel pipes.

 

[panason1c]

It's not waxing...

It's not likely to be water freezing either in the temperatures we are having, it will be air being drawn into the fuel pipes.

The OP has already said his overnight temps are -7 and -8 degrees.........(must be in scotland i guess)



this only happens when we have very low tempratures and the car has been sitting over night out side , the temp was minus 7 , it happened before when we had minus 6/8

 

[spike60]

It could be air in the system but i believe in keeping all options open, bear in mind that the OP could still have summer diesel (no anti waxing additive) in the fuel tank, and purchased from a petrol station that has not had a winter diesel delivery due to low sales turnover , ie..rural garages. (i used to work for Esso at Avonmouth a few years ago)

I ran an old Polo 1.9D on 50% cooking oil through the worst of last winter in the north of England with no problems when it was about 10c colder than seen so far this year. Be interested to know if many drivers had problems last year confirmed as waxing, I was unaware of any. The wax I have seen does not seem to readily all absorb back when the fuel warms up, I have seen it in the bottom of tanks in the summer time, it looks like dull glitter. Changing the filters is the only way I have seen it fully removed.

 

[charliefarlie]

Hi all , Yes i live in Scotland where its a dashed site colder than england ever will be but no matter , have parked it faceing downhill , the plastic pipes and o rings can you get these as a kit or do you take it to your nearest dearest merc dealer?

 

[Dieselman]

Just buy the pipes, they are easy to fit.

 

[SilverSaloon]

the pipes are available at the merc dealer, or i would just get the orings as per my post above. there probably isnt any need to replace the pipes. cost of pipes will come in at around £50 and you still will need to buy a few other orings (shut off valve, prefilter etc) too. if you get the oring kit above it comes with all the orings to do it all, just pop off your existing pipe, take off the old oring, put the new one on, pop the pipe back on. they clip on using fragile horshoe-connections so be careful when unclipping the pipes. you'll also need to crank a bit afterwards (so have a spare battery or charger/jump leads on standby) incase the battery goes flat doing so.

Worth replacing the spin on main fuel filter at the same time too.

 

[renault12ts]

Hello & thanks for suggestions & thoughts re none starting in cold weather yes its been cold here since last week minus 5 most days and 7 the other day since then its milder again the car starts fine now no problem , havent seen air bubles in pipes at all , shall try parking down hill when frosts return or may well just shift me trikes and put the bugger it in the garage .

Charlie, fill in the user CP and tell us where you live...could avoid some of the discussion we have had. Where I live we have had no minus temperatures this winter so far ...Belfast. Though, last year we did have a week when the temp did not rise above -10 C...no waxing.

 

[SilverSaloon]

i'm in scotland.... had a few really cold nights. 100% waste veg oil in both cars, both cars start no problems.

as stated before its 99.9% bad seals - get the orings changed. its not going to be waxed diesel - if diesel did wax up my WVO would be set solid!!! lol