745TD black smoke/white smoke....

[740-estate-nut]

hi y'all.. I am still trying to get to the bottom of this, but I have a question for all the "Heavy Fuel" gang...
Whats the difference between black smoke and white smoke coming out of the exhaust??
You see, I am still a diesel novice.. I am, or was, more of a petrol head.. so if there was any smoke at al lcoming out of the exhaust, it was time for a service... but I have already fully serviced my D24T, glow plugs, relay, oil/air filters, new oil.. (semi synthetic..10w40 would that be too thin???)but still I am having the same problems...
can anyone help??


For all the info, see this posting
http://www.volvoforums.org.uk/showthread.php?t=20567
Thanks
Simon

Hi most of the time black smoke is unburnt fuel white is water (until the car warms this could be ok)
On a diesel black smoke is fairly common and is the compression burnt fuel.

Black smoke can be a sign of a stuffed engine White can be head gasket although can be other thing as can black smoke.

Charlotte

[Peter Milnes]

I would have your head gasket checked. A compression check will tell you. This is fairly common when diesels have not been serviced regularly in their past life. On 740s it is asign that the head retighten at 1,000 miles from new or reconditioning has not been carried out. The water pump gasket may have been damaged if the cambelt has been changed. On your model year the cambelt tension is set by moving the water pump.

Al the best, Peter.

[mycoleptodiscus]

You need to have your injection timing checked and adjusted. There is a procedure at my BLOG scanned from the factory manual. Improper ignition timing will cause LOTS of unburnt fuel and lots of black smoke. From reading your other posts, it seems like you have bigger problems though... Pump shaft seal coul dbe bad and you could be sucking in air. See my BLOG- lost of helpful information to wade through...
http://volvoturbodiesel.blogspot.com/

[alsner]

I noticed that its a turbo diesel, I white smoke can mean your turbo is in need of refurb/replacement on a petrol car (if water pipes/gaskets are all ok), i think its also the same for diesels, I can't guarantee it though as I can't remember where I recall the info from.

I've driven diesel turbo's (mostly taxis) in the past with buggered turbos and white smoke was there on most occasions....

some Q's

Mileage?
Is the smoke on tick over or at revs with acceleration?
How is the power on the engine, does it pull like it used to, is the turbo kicking in as it should still?
Have you any service history to show when the turbo was last replaced? or is this the original turbo?

I hope I'm totally wrong and some of the other suggestions work out better. Sorry

Ali

[740Estate]

Black smoke =Fuel
Blue smoke (or bluish white smoke) = Oil
White smoke = Water/Coolant

[SteveJ]

Hello Simon,

Back or white smoke could be fuel (yes even white smoke). Check the pump timing. Dirty injecters (try injector cleaner in fuel). Restriction in inlet, (wrong air filter, dirty inlet manifold).

Blue smoke can be so light in colour as to appear to be white so, could be oil. Had this problem myself with a customers car and eventually found it to be prematurely worn valve guides, (they are very short in this engine). The problem was only manifest when warm and pulling away from lights etc.

Disconnect the hoses between the turbo and manifold. How oily? There is always oily resdue inside but excessive oil would suggest turbo seal failure.

You could be using to thin an oil for such an old car.

Apparent white smoke could be head gasket, this was a known problem on this engine. Any oil in expansion tank? Any bubbling visually evident in tank? Are you losing water past the cap (overpressurising). Engine overheating? Oil in water?

As usual with cars nothing is straight forward. Good luck.

SteveJ

can yas strobo time diesels ?

Me kina knows not ........ But is it poss to tap in to the inj cables & be really clever ?


If not how do yas do it ? like statick timing on a petrol ?

Originally Posted by J..M

can yas strobo time diesels ?

Me kina knows not ........ But is it poss to tap in to the inj cables & be really clever ?


If not how do yas do it ? like statick timing on a petrol ?

You can use an injection pulse adapter to dynamically time a diesel with a timing light, but I have no idea what the spec would be on one of these things to do it that way.


As far as white smoke, that can aside from water, be from incomplete combustion from a number of reasons.bad timing weak compresion leaky valves, etc.
----------Robert