Noisy Engine when cold

My Diesel is normally smooth and quiet, drives lovely and the small amount of wind noise drowns out the engine! But I've noticed a few times its a bit rattly when you first start up from cold, a minute running and it settles down, then over this very cold down to -11C period i've not been using it as i've been away, its sat for a week at these temps, so I get back and start it up, starts on the button with just a 3 sec glow plug delay. Then as it returns to idle it starts rattling noisily like its shaking in its mounts, rev it and it runs perfectly it just shakes on idle, so I rev again and the shaking reduces and eventually after a minute or two idle returns to normal and all is well rest of the day it runs like a dream, as weather has warmed up itll be fine tomorrow I'm sure.

Is this just diesel's when cold, or poor quality supermarket fuel? Not something I'm familiar with, and a bit disconcerting. Anyone noticed anything similar?

The joy of a diesel I would think. My Freelander was rattly sometimes on cold start.

What you are describing sounds like typical diesel sounds. Although they have become a lot more smoother over the years when it get really cold you will get the typical diesel sound. Also keep in mind its "just' a 4 cylinder and the less cylinders the more it will shake and rattle.

Yup - it's a diesel. My current Audi is 4 pot 2.0 TDI and that is noisy when cold but soon evens out when it is warm.

Considering the downright violent combustion process of a high speed compression ignition engine (i.e. a Diesel) they are remarkably quiet really. Unlike petrol engines where the fuel is injected in a single optimal charge and burns with the ignition trigger of the spark plug these modern diesels work very differently. Early diesels with completely mechanical injection systems used to have the fuel injected when the piston was at the top of its stroke - at maximum compression and the fuel would detonate instantly (because rapidly comressed air is hot) and drive the piston down on it's power stroke - audible by that characteristic noisy knocking noise.

To make the engine smoother and to extract the maximum energy from the fuel these advanced diesels actually inject the fuel in several phases as the piston is rising on it's compression stroke. The result of this is that fuel starts burning earlier and is more complete (lower emmissions) and is also smoother aand that also reduces the harshness of the engine's aural note. Our man from Bell Auto Services will be able to confirm the number of injection phases I'm sure?

Thanks Guys interesting info, it's my first diesel I've owned so guess i'm just not used to it, so will remember to keep the revs up if it does this again just to get the heat into it for the smoother combustion.

(13-02-2012 12:29am)PhilSkill Wrote:  My Diesel is normally smooth and quiet, drives lovely and the small amount of wind noise drowns out the engine! But I've noticed a few times its a bit rattly when you first start up from cold, a minute running and it settles down, then over this very cold down to -11C period i've not been using it as i've been away, its sat for a week at these temps, so I get back and start it up, starts on the button with just a 3 sec glow plug delay. Then as it returns to idle it starts rattling noisily like its shaking in its mounts, rev it and it runs perfectly it just shakes on idle, so I rev again and the shaking reduces and eventually after a minute or two idle returns to normal and all is well rest of the day it runs like a dream, as weather has warmed up itll be fine tomorrow I'm sure.

Is this just diesel's when cold, or poor quality supermarket fuel? Not something I'm familiar with, and a bit disconcerting. Anyone noticed anything similar?

If it is any consolation mine was exactly the same as yours yesterday (-6C) and I thought it was pulling itself apart!
Settled down after a minute or so. Went when I blipped the throttle.

(13-02-2012 12:29am)PhilSkill Wrote:  My Diesel is normally smooth and quiet, drives lovely and the small amount of wind noise drowns out the engine! But I've noticed a few times its a bit rattly when you first start up from cold, a minute running and it settles down, then over this very cold down to -11C period i've not been using it as i've been away, its sat for a week at these temps, so I get back and start it up, starts on the button with just a 3 sec glow plug delay. Then as it returns to idle it starts rattling noisily like its shaking in its mounts, rev it and it runs perfectly it just shakes on idle, so I rev again and the shaking reduces and eventually after a minute or two idle returns to normal and all is well rest of the day it runs like a dream, as weather has warmed up itll be fine tomorrow I'm sure.

Is this just diesel's when cold, or poor quality supermarket fuel? Not something I'm familiar with, and a bit disconcerting. Anyone noticed anything similar?

Mines been the same on very cold start ups? and it's my first diesel to.

I'm glad i read this post because i was getting concerned as mines been doing it since last Thursday, but now the weather is becoming milder hopefully it should sort itself out..

(13-02-2012 09:10pm)cutter7 Wrote:  Mines been the same on very cold start ups? and it's my first diesel to.

I'm glad i read this post because i was getting concerned as mines been doing it since last Thursday, but now the weather is becoming milder hopefully it should sort itself out..

Thanks guys, it does sound quite violent initially, so looks like a feature.

Hey cutter pretty sure we passed each other near Tesco's roundabout Sunday, I saw the black lettering!? Mine was still covered in Snow! Funniest thing the snow flicks off the front onto the windscreen continuously until it runs out, was making me laugh... except I couldn't see where I was going.

(13-02-2012 09:37pm)PhilSkill Wrote:  Thanks guys, it does sound quite violent initially, so looks like a feature.

Hey cutter pretty sure we passed each other near Tesco's roundabout Sunday, I saw the black lettering!? Mine was still covered in Snow! Funniest thing the snow flicks off the front onto the windscreen continuously until it runs out, was making me laugh... except I couldn't see where I was going.

yes i do remember! you were heading towards me on the Southam road by Wickes as i was going towards town.

I also noticed your landslide from the roof!! i have added black grill and side vents today, looks great on the 22's

Small world...see you about.. give me a flash next time.

(13-02-2012 09:59pm)cutter7 Wrote:  yes i do remember! you were heading towards me on the Southam road by Wickes as i was going towards town.

I also noticed your landslide from the roof!! i have added black grill and side vents today, looks great on the 22's

Small world...see you about.. give me a flash next time.

Yep, Thought it must be you as not many will have done the black lettering conversion. I would have flashed had I not been busy trying to get the snow on the roof to slide off the back or sideways rather than cover the windscreen as i stopped for the roundabout!