Volvo MD7 Smoking

[aquaholic]

Quite new to diesel engines so dont know too much I am afraid, what i have noticed since owning this boat is that even when warm it chugs out a little blue smoke, question is i realise the engines very old but hoped it would last another season, other than the smoke it seems fine. Is it terminal or is it possible to have it rebuilt and to what cost, or would it just have to be replaced ??????

 

[OGITD]

Initially I would try some injector cleaner in the fuel and some “Diesel Stop Smoke” for the oil (as part of an oil change) all from Part Co or your local motor factors.
Different colours of smoke indicate different things, but in the main if it’s not too excessive, using too much fuel or burning too much oil then treat it with the above and see what happens.

 

[VicS]

Blue smoke is usually considered to be sign that it is burning a bit of engine oil but if the oil consumption is not excessive and it starts and runs OK you know what they say:

"If it ain't broke don't fix it"

A few pints of oil for topping up is going to be a whole lot cheaper than a rebuild or a replacement.

 

[RichardTaylor]

[ QUOTE ]


"If it ain't broke don't fix it"



[/ QUOTE ]

Our MD7a is a smokey old unit, which was partially resolved by having the injectors serviced, however the engine has proved reliable for 4 years and despite having a "replace fund", I see no reason yet to waste my money until it proves to be a liability.

 

[Leighb]

I have a MD7A which runs well and delivers good power, but does tend to be a bit smokey, especially when starting.

Smoke is greyish, def not white or blue, oil consumption is zero in 60 odd hours this year. Also seems to be some oily drops on water when first started , ? unburnt diesel.

I had been wondering if it might be worth having the injectors serviced to try and reduce the smokiness.

Would you agree it is worth it, and what is likely cost?

 

[BobnLesley]

...even when warm it chugs out a little blue smoke...

To paraphrase the great JC: you lucky b@st@rd! You lucky lucky b@st@rd! 'A little blue smoke' what would I give for a 'little' blue smoke! /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif

We have an MD6A which when purchased in 2000 suffered from a little blue smoke and like the earlier poster, we budgetted for an early replacement. We've currently got a 'moderate amount' of blue/grey smoke; but having got as far as Greece and put perhaps another 12-1500 hours on the engine, we're far more relaxed about it. I would pass on the advice of a very sage Engineer we met in Spain (it had lots of black smoke then, until he renewed the injector nozzles):

'If an auxilary marine diesel engine is starting easily, then there's nothing much wrong with it; don't worry about looking for lots of smoke - watch for lots of water at the exhaust instead. Other than that, just keep it topped up with fresh fuel & oil, change or clean the filters regularly and otherwise, just leave it the feck alone!

This is some of the best advice I've had since we started sailing. /forums/images/graemlins/ooo.gif

 

[aquaholic]

I am really not sure, as stated iam new to diesels, iam sure if you start a thread you will get a response.

 

[aquaholic]

Thanks for the responses, will give the additives a go, and if not i wont worry too much as she does start on the button

 

[double_ender]

We have a volvo 7b and just like the other replies does smoke a bit. I think the ammount of smoke does depend a bit on various factors, like how warm the engine is, the load, revs etc.

Also the the conditions like sunshine,damp air, air temp seem to make any smoke more or less visible and also whether the colour is bluey, grey or whiteish!

Our 7B has done 2500hrs since '96 when we got the boat and I have a spare one sitting in the garage to encourage it to keep going

 

[gandy]

I'm in the same situation. MD7A runs and starts OK, but smokes. I've decided that there's too much risk in overhaul work on such an old unit, and will leave well alone aside from normal servicing. The problem with these old engines is that once you start taking it apart its hard to stop. Parts are expensive, and some are no longer available.

I gave myself a scare last winter when a thermostat replacement went wrong - the connections for thermostat and pipework were all so corroded that at one point it looked like I'd need a new exhaust manifold to stand a chance of getting it together leak free.

 

[RichardTaylor]

[ QUOTE ]

I had been wondering if it might be worth having the injectors serviced to try and reduce the smokiness.

Would you agree it is worth it, and what is likely cost?

[/ QUOTE ]

A local Diesel specialist (Panda - Fareham) charged around £40 to service 2 injectors back in the spring of 2007. However I was warned that depending on the state of the injectors they may have cost around £50 each to service and repair

 

[aquaholic]

Will leave well alone then, have changed the oil and filter, replaced the rubber exhaust hose and fitted a new impellor. Hopefully should be good for a while yet.