Are Diesels slower in Winter?

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Simon_M

MB Enthusiast
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Wife is complaining the car is 'sluggish' in the recent mornings. I told her that it was just because it is very cold at the mo and diesel thickens in the colder weather.

It seems to be from starting after the car is sat overnight. I have not experienced it myself but she says it did not do it last year and maybe the Brabus chip is fooked.

My Passat is like a dog (also diesel) first thing so I am not really fussed.

Am I bullshyating her or is the car playing up? any advice?

Simon
 
Wife is complaining the car is 'sluggish' in the recent mornings. I told her that it was just because it is very cold at the mo and diesel thickens in the colder weather.

It seems to be from starting after the car is sat overnight. I have not experienced it myself but she says it did not do it last year and maybe the Brabus chip is fooked.

My Passat is like a dog (also diesel) first thing so I am not really fussed.

Am I bullshyating her or is the car playing up? any advice?

Simon

Dont push a cold car anyway. However it does thicken up. I notice this more when I run on veg oil - very slow if its not mixed much with petrol/diesel.

I suspect straight diesel aslo thickens and has the same affect, but just not as bad.

I more or less ignore hard gearshifts/sluggish type issues if the car is not at its standard temp. Only worry if it does strange things once nice and warm.
 
Good quality branded diesel has a different formulation in winter, and I don't think you should notice any difference in performance at the sort of temperatures we get here.
 
it's more than lightly a traffic cone stuck under the car, it will work it's way free soon!

Sorry could not resist.
 
I have certainly noticed this in the last few days when temperature has been near 0, really sluggish on full throttle below 3,000, more than usual anyway ;) Once warmed up OK though.
 
I've found that all cars are not on top form in very cold weather having been stood over night - both petrol and diesel.

Diesel does seem to be affected more though - louder, more clatter, etc until up to normal operating temperature.

Dread to think what it's like in places where it's REALLY cold.


Come on dieselman. Your forum needs YOU!
 
I'm probably in the minority here, but cold weather seems to make my cars perform better - petrol and diesel. Certainly once 'warmed up' anyway.

I'd always assumed that the colder air was more dense = more oxygen when filling the cylinders?

Will
 
LOL at the cone!

Yeah, she always pushes it too hard when cold and rarely waits for the ignition light to go out before starting it, despite abuse from me every time she does it.

I'll take it for a run at he weekend and probably diagnose a shoe or bag under the pedals!

S
 
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I'm probably in the minority here, but cold weather seems to make my cars perform better - petrol and diesel. Certainly once 'warmed up' anyway.
My c230k goes like a rocket on cold mornings! Much more responsive and needs a lighter touch in order to make safe progress!
 
My c230k goes like a rocket on cold mornings! Much more responsive and needs a lighter touch in order to make safe progress!

I agree, mine definately used to as well :)

Will
 
I'd always assumed that the colder air was more dense = more oxygen when filling the cylinders?

Will


100% correct, especially on forced induction cars, they will have more power in winter than in summer and the manufacturers adjust the ECU to suit...
 
I'm probably in the minority here, but cold weather seems to make my cars perform better - petrol and diesel. Certainly once 'warmed up' anyway.

I'd always assumed that the colder air was more dense = more oxygen when filling the cylinders?

Will

I agree - theoretically that should be the case - warmer ambient temperatures degrade performance.

Maybe I read it wrong but I think the OP was coming from the perspective of a cold start, ie not yet up to operating temperature.

If memory serves, air is at it's most dense at 4 deg C, but as it enters the engine bay and then through to the combustion chamber it warms up quite a bit, and that increase in temperature more than offsets the maximum density in perfect ambient temperatures.

So on that basis you want ambient temperature to be much cooler still than 4 deg C - especially for forced induction cars, as it gives the intercooler a head start!!
 
Every diesel i have ever owned has been a tad sluggish from a cold start, reluctant might be a better word and i cant blame them either!



Lynall
 
Hmm .. not noticeable on either of ours.
 
When the cylinders, pistons etc are warm then we very very rarely see weather cold enough for it to affect the fuel itself.

It's simply the car taking longer to warm up.

Dave!
 
So true:D well all mine were Landrovers:rolleyes:



Lynall
 
What grade of oil are you using? Changing to an oil having lower/wider viscosity at low temperatures might help- It will definitely help the starting! Or you could fit a coolant preheater?
 
Air gets denser as the temperature drops.

Correct, it needs to be nice and cold/dense i.e. more oxygen molecules to create a bigger bang in the cylinder.
 

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