Blues Smoke - Advice Please

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andreas_t

Active Member
Joined
Oct 5, 2005
Messages
61
Location
Kenilworth
Car
GT C
Folks,

I hope you can offer me some advice. I just came back from the stealers - I had noticed in the last few weeks whiffs of smoke when stationary (hot or cold engine) and bad diesel consumption. The stealer diagnosed a faulty air temperature sensor and replaced it claiming that this will fix the heavy consumption part of the problem - I've only done about 20 miles since, so I need to keep an eye on it.

The stealer's mechanic also said that I'm burning oil ! - I questioned that, on the basis that the oil level meaures OK (8K miles since last service and no top up needed ever - another 6K to go for a Service A). MB want to have the car in for 'a couple of days' to run checks on it (£££££££ !) - I declined politely, saying that I'll monitor it and take it back if the condition deteriorates.

The truth is that I can still see smoke (not as much as before) but where's the oil coming from if the measurement is OK ? - I also thought it acceptable for a diesel to burn a bit of oil.

Any ideas on what - simple - (meaning 'cheap' - this problem comes after an injector replacement mid-December) checks I can do to verify whether this is a big problem or not ? Any advice or past experiencs will be welcome. The car is a W210 E220CDI with 87K on the clock (and just passed its MOT last week at 2.08 emissions - but the MOT chap didn't say anything about oil burning and he's usually quite thorough)
 
If the engine is genuinely not consuming oil then I would go for a dribbling injector, worn out MAF sensor or sticking EGR valve.

Is there any undue smoke when driving generally?
 
Dieselman said:
If the engine is genuinely not consuming oil then I would go for a dribbling injector, worn out MAF sensor or sticking EGR valve.

Is there any undue smoke when driving generally?

Dieselman, thanks for the reply. To answer your questions:

1. I have just done 300 miles, checked the oil and no change. This makes it about 8.5K miles since last service with no top-up whatsoever. The injectors were replaced by MB about 2K miles ago. And when MB checked it for smoke on Monday, they said the injectors were OK. Their claim that the faulty air temperature sensor would fix the consumption problem went out the window today - I normally get between 45 and 48mpg on this particular journey, but today I struggled to get 40 (due to roadworks and speed cameras - otherwise, it would have done 38 at the best). They are convinced that it is blue smoke that comes out and predict that the turbo is done (how can this happen on a car which has done 95% of its mileage on m-ways ferrying only one - overweight - passenger, begs some explaining ...)

2. Today, I could still see smoke when stationary and when I 'tuned' it down the M40 (appeared when I floored it accelerating from 70ish to whatever ....).And the other thing is that the smoke doesn't smell of oil ! - more like diesel. Does synthetic oil smell different when burning ? To recap, up to now, the only thing that the car seems to be burning (which it shouldn't !) is diesel. How long would you suggest would be reasonable to give it (monitoring I mean) before having words with the dealer ?
 
andreas_t said:
Dieselman, thanks for the reply. To answer your questions:

1. I have just done 300 miles, checked the oil and no change. This makes it about 8.5K miles since last service with no top-up whatsoever. The injectors were replaced by MB about 2K miles ago. And when MB checked it for smoke on Monday, they said the injectors were OK. Their claim that the faulty air temperature sensor would fix the consumption problem went out the window today - I normally get between 45 and 48mpg on this particular journey, but today I struggled to get 40 (due to roadworks and speed cameras - otherwise, it would have done 38 at the best). They are convinced that it is blue smoke that comes out and predict that the turbo is done (how can this happen on a car which has done 95% of its mileage on m-ways ferrying only one - overweight - passenger, begs some explaining ...)

2. Today, I could still see smoke when stationary and when I 'tuned' it down the M40 (appeared when I floored it accelerating from 70ish to whatever ....).And the other thing is that the smoke doesn't smell of oil ! - more like diesel. Does synthetic oil smell different when burning ? To recap, up to now, the only thing that the car seems to be burning (which it shouldn't !) is diesel. How long would you suggest would be reasonable to give it (monitoring I mean) before having words with the dealer ?

If the smoke smells of diesel then it is diesel.

Give it about a week to be sure.
 
Might be totally OT here, but in Gambia petrol stations were known to dilute the diesel with oil and or kerosene to make a couple of extra dalasis... This would make the car smoke more than usual...

Also, when your injectors were replaced, could some oil ahve gotten into a pipe somewhere (like the exhaust), and is slowly being burnt? (i.e. does it smoke from the instant you turn the car on, or only after the engine has had time to warm up?)

Finally, BLUE smoke (imo) is definetly oil-based... two-strokes are known for their pretty blue smoke from the oil they burn...
 
Problem with the smell is that it's quite hard to tell ! - It certainly doesn't smell like the stuff which comes out of a 2-stroke; more like diesel with something in it. And it is definitely greyish-brown with black overtures - not blue (unless I'm getting colour-blind ....).:confused:

The smoke is there from the word go. More pronounced once I come on a roundabout or traffic lights after a m-way run. Little evidence of smoke when in 'park' - most of it when in 'drive' and stationary. Need to get my son to put it in drive while I'm having a sniff at the exhaust (and remove him from my will for the duration - in case his foot slips accidentally ....)

Thanks for the suggestions and all your helpful comments - I'll give it a week or so and take it from there.:)
 
andreas_t said:
Problem with the smell is that it's quite hard to tell ! - It certainly doesn't smell like the stuff which comes out of a 2-stroke; more like diesel with something in it. And it is definitely greyish-brown with black overtures - not blue (unless I'm getting colour-blind ....).:confused:

The smoke is there from the word go. More pronounced once I come on a roundabout or traffic lights after a m-way run. Little evidence of smoke when in 'park' - most of it when in 'drive' and stationary. Need to get my son to put it in drive while I'm having a sniff at the exhaust (and remove him from my will for the duration - in case his foot slips accidentally ....)

Thanks for the suggestions and all your helpful comments - I'll give it a week or so and take it from there.:)

If the smoke is grey/black in colour it is very likely to be unburnt diesel.
 

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