D5 Black Smoke Safari

[outnumbered]

Intercooler

[skyship007]

Originally Posted by flashingblade

Only smokes with hard acceleration. and its black soot coming out.

For what its worth, not much turbo sound when revved or on the move, and, it likes to rev freely up to 4K plus (as if the Turbo is not boosting at lower revs)

So, I was thinking intercooler leak or turbo veigns stuck.

This guide below mentions a lot of different black smoke causes relating to the turbo and injection system. Might be worth getting the codes read if there is nothing obviously wrong with the turbo.

http://www.bmwforums.info/general-gu...ng-issues.html

One thing to ignore is the tip about fuel additives, as they will not help clean an EGR or Cat that already has significant deposits.

[chrisdc]

Originally Posted by skyship007

but I would keep the first run to 5K miles max if the oil turns black fairly quickly.

Could you elaborate on this please? I thought oil turning black quickly was normal for a diesel. If memory serves, my oil looks black after just a lap around the block! I usually let the oil drain for at least an hour, usually two, before i put the sump plug back. And i always warm the engine first, even if i have to make a special trip somewhere first.

[skyship007]

Originally Posted by chrisdc

Could you elaborate on this please? I thought oil turning black quickly was normal for a diesel. If memory serves, my oil looks black after just a lap around the block! I usually let the oil drain for at least an hour, usually two, before i put the sump plug back. And i always warm the engine first, even if i have to make a special trip somewhere first.

A diesel will tend to blacken the oil faster than a petrol engine will, but if the oil turns black very quickly after an oil change, it does tend to indicate the engine had some degree of sludge in the sump.
When changing from a conventional oil to a full synthetic or high mileage oil, it is considered good practice to keep the first oil change interval to half of the recommended max OCI. If you suspect an engine has some degree of sludge, then it is worth using an idle only flush additive just before the oil and filter change to help clean things out (Liqui Moly idle flush is a good one).

Unfortunately if an engine is seriously sludged (Flickering low oil pressure warning after a good run at hot idle, or srewdriver needed to help drain the oil from the sump plug), the sump should be removed and the oil pump intake screen cleaned if possible (Easy on some engines, but a nightmare on others). It might even be necessary to clean the top end, particularly if the engine has a VVT unit or a sensitive turbo, although that is going to be one big job.

If you get sludge form when the oil type and change interval have been sensible, it could indicate a potential head gasket leak, as the anti freeze reacts with the detergent and dispersant additives included in the engine oil.

Many cases of sludge result from a combination of the use of a cheap oil, too long a change interval and too much time at idle.
The max OCI figure is only good if you use a top quality major brand full synthetic in an engine in good condition that does not spend too much time at idle or doing short trips.

Here are the guidance notes for the use of Mobil 1 HM 10/40 oil, that might be of interest:
http://www.mobil.com/USA-English/Lub...leage_Oil.aspx (See note 1 about short initial OCI's)

[outnumbered]

change the oil in the barge every six month and it still is black a day after putting the new in.
mike

[skyship007]

Originally Posted by outnumbered

change the oil in the barge every six month and it still is black a day after putting the new in.
mike

Sounds like you have a layer of sludge in the sump. This is the type of product that will help clean it out just before the oil & filter change:

http://www.liqui-moly.de/liquimoly/m...ne%20Flush.pdf

[outnumbered]

well thats interesting i must have a layer of sludge in the new one as well cause that's mucky the day after the new oil went in . and owning disel for the last 20years or so that as always been the case.
must be all the dodgy cars that i am getting perhaps.

[GJB]

Originally Posted by outnumbered

well thats interesting i must have a layer of sludge in the new one as well cause that's mucky the day after the new oil went in . and owning disel for the last 20years or so that as always been the case.
must be all the dodgy cars that i am getting perhaps.

Agree have run diesels for over 35 years and always oil is dirty day after change it proves the oil is doing its job in holding dirt in suspension.

[skyship007]

Originally Posted by GJB

Agree have run diesels for over 35 years and always oil is dirty day after change it proves the oil is doing its job in holding dirt in suspension.

I've been around diesels just as long and I've never had an engine dirty it's oil the very next trip if the oil was at max temp before draining. I did use an idle flush on any engine that I thought might have deposit issues which does make a difference.

If the oil is run for too long the dispersant additives fail and it starts to dump sludge, so if you then change the oil it will turn black even though the engine is new.
So in some ways the fact the oil always turns black after one trip can be a hint that the previous oil change interval was too long, or the type of oil used lacked enough dispersant additives to keep the Carbon cleaned up by the detergents in suspension.

If you have been using a conventional or semi synthetic oil and then switch to a top quality full synthetic, once the block has been cleaned up (Might take several shortish oil changes or an idle flush etc), you will notice the new oil stays clean longer.

An engine that has to suffer too much time at idle, or short trips will dirty it's oil much faster due to incomplete combustion issues, as will one with bad rings or injectors etc, although nothing will beat a head gasket leak for causing black death.

[outnumbered]

lets agree to disagree and yes i use the top Quality oil.
mike