White Smoke from Diesel - Diagnosis pls

[Gypsy]

I have a Bav44 2002 with a Volvo D2-55 which has about 2000hrs on the clock without any dramas.

Normal revs when motoring are less than 2000 with a 'sweet spot' of 1800 for relative calm seas. I seldom go above 1800 for any duration.

Over the past 2 weeks I have been on passage up the E coast of Aust and noticed a light white smoke from the exhaust in the morning when temps about 12-15C and revs between 1800 and 2200 if I had to increase the speed to make a destination. It is very light in colour and hard to see sometimes. Reducing revs to 1800 seems to stop it.

I am not losing coolant, there is no sign of water in the oil or in the rocker cover and there is no sign that the engine is labouring.

When I read the books or the web the most likely suggestion seems to be unburnt fuel meaning the injectors need a clean. What do the trusty forum experts think?

If the injectors need a clean, is it done in situ or do the injectors and the injector pump need to be removed and taken to a workshop?

Tks in advance.

 

[Hoolie]

Ours also has a very fine and barely visible white smoke only noticeable with a following wind. I've assumed it's an age problem (not me - the engine!) and consigned it to the list of things to be worried about when the 1001 more important things have been done.

 

[mikemonty]

Over the past 2 weeks I have been on passage up the E coast of Aust and noticed a light white smoke from the exhaust in the morning when temps about 12-15C .

Looks like you might be seeing water vapour - given the dewpoint seems to be about that temperature according to:-

http://www.findlocalweather.com/weather_maps/dew_points_australia.html

For the avoidance of doubt - that's not a bad thing - water vapour is meant to come out your exhaust - just that I wouldn't expect you would see that normally in Oz - pretty normal in Scotland!

 

[Gypsy]

Mike, that would be a nice solution/answer. I did consider it as it seemed to occur only in the morning, but didn't research it.

I have had a 'rest' in Coolangatta (NSW/QLD) border for a couple of weeks and will continue Nth in a few days so I will watch closely as the temperatures will be lifting by the day.

 

[Sneaky Pete]

Looks like you might be seeing water vapour - given the dewpoint seems to be about that temperature according to:-

http://www.findlocalweather.com/weather_maps/dew_points_australia.html

For the avoidance of doubt - that's not a bad thing - water vapour is meant to come out your exhaust - just that I wouldn't expect you would see that normally in Oz - pretty normal in Scotland!

+1 Yes happens to all 4 stroke engines in cooler damp weather as engine and exhaust heat up to normal running temp it will disappear, I dont believe this affects you but if it continues then it is unburnt fuel and may require the injectors to be serviced.

 

[Topcat47]

Steam dissipates on the mooring, white smoke kinda lingers about. I was advised it was probably a sticking injector. Sadly when you have a pre-combustion chamber, spraying injector cleaner in the inlet manifold doesn't help. A lorry driving mate advises a good squirt of Redex in the fuel.

 

[stuey_two]

One other cause of "white smoke" can be an inadequate supply of sea-water into the exhaust. allowing hot exhaust gases to turn some of the seawater into steam. This can be
caused by failing sea water pump or - as happened on our boat (Nanni engine) - a (partially) blocked exhaust injection elbow. This we cured by replacing the elbow - we could not clear the blockage.

 

[savageseadog]

Steam dissipates on the mooring, white smoke kinda lingers about. I was advised it was probably a sticking injector. Sadly when you have a pre-combustion chamber, spraying injector cleaner in the inlet manifold doesn't help. A lorry driving mate advises a good squirt of Redex in the fuel.

You can buy injector cleaner to put in fuel from motor factors, no idea how effective it is.

 

[Sneaky Pete]

I am not sure if like car or commercial diesels you can exchange a set of injectors for a reconditioned serviced set, take old set out, exchange along with money at diesel engine factors, and refit into engine done in a few hours, does anyone know?

 

[mikemonty]

Steam dissipates on the mooring, white smoke kinda lingers about. I was advised it was probably a sticking injector. Sadly when you have a pre-combustion chamber, spraying injector cleaner in the inlet manifold doesn't help. A lorry driving mate advises a good squirt of Redex in the fuel.

Guys!
The OP saw "white smoke" - the dewpoint was close to, or at, the ambient temperature when he saw it.
For him, it only happens in those circumstances - let's apply Occams Razor and settle for the most probable cause rather than getting him worked up about the more unlikely (expensive) scenarios.
Unless, of course this is purely a discussion group.

I've also got reservations about "the vapour not being water if it doesn't disappear once the engine is up to temperature".
Warm air "soaks up" water that MUST condense out at dewpoint - a hot exhaust will carry as much - nay, more, water than a cool one. This water might condense visibly into "mist" if it doesn't get dissipated enough to very quickly get to below its vapour pressure and evaporate away.
So even with a hot exhaust its perfectly normal to see water "vapour" (mist) continuously if, for example, you were motoring downwind on a cool day with a light wind and a high dewpoint - there is a little bubble of condensate following you - it does not mean that your engine is buggered.

 

[LionsDen]

Hae you checked to see if the coolant level or engine oil level are correct as these items are noted in my evc manual for my D6 435 engines if blue or white smoke is prevalent from the raw water exhausts {touch wood this does not apply to my boat}

 

[Heckler]

I have a Bav44 2002 with a Volvo D2-55 which has about 2000hrs on the clock without any dramas.

Normal revs when motoring are less than 2000 with a 'sweet spot' of 1800 for relative calm seas. I seldom go above 1800 for any duration.

Over the past 2 weeks I have been on passage up the E coast of Aust and noticed a light white smoke from the exhaust in the morning when temps about 12-15C and revs between 1800 and 2200 if I had to increase the speed to make a destination. It is very light in colour and hard to see sometimes. Reducing revs to 1800 seems to stop it.

I am not losing coolant, there is no sign of water in the oil or in the rocker cover and there is no sign that the engine is labouring.

When I read the books or the web the most likely suggestion seems to be unburnt fuel meaning the injectors need a clean. What do the trusty forum experts think?

If the injectors need a clean, is it done in situ or do the injectors and the injector pump need to be removed and taken to a workshop?

Tks in advance.

Probably condensation, by the way 1800 revs is too low, you risk carboning the engine up by not loading it enough.
Stu

 

[Gypsy]

Reporting Back

Thanks to all forumites for your input. Here is the result.

As much as I would have liked it to be a dew point explanation, the evidence pointed to something else, so after my side trip to NZ I decided to look at the exhaust elbow - wow, we have a cholesterol problem here! This engine needs a course of 'Lipitor' to sort out the narrowing of the arteries!!!

The exhaust elbow aperture was reduced by about 50% and one of the water feed ports was blocked. Add to that, there were large air bubles in the cooling water flow which I have since put down to a bad gasket in the raw water filter, which reduced the cooling capability.

With the help of a hammer and a screwdriver I was able to de-coke the elbow and clear the water port blockage, but I will replace the elbow soon. Lots of work to ensure all the raw water pipes and joints were in good shape. In the end I think the greatest issue with the water flow was a stretched gasket sealing the raw water filter basket.

Net result, no white smoke and good water throughput.

Another forum succesful diagnosis exercise.

Thanks