White Smoke from my Engine

Jon magowan

Jon magowan

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Volvo penta D1-30 F
750 hrs.
New exhaust elbow (original extremely coked up )
Injector nozzles replaced 2.5 years ago at 540 hrs by Volvo dealer.
Engine starts easily and runs well.

The problem is I get a steady stream of white smoke at full throttle. It disappears as soon as I reduce the rpm. The level of coolant remains constant and in every other respect the engine is performing well.
It’s concerning me that there is something amiss.

Any ideas please ?
 
When I had a similar problem I started by checking the cooling water strainer, then blowing through the hoses for the sea water system. Next came a new impeller, replacing the old one which looked OK.
The exhaust elbow was clean enough which left the heat exchanger to flush through.

A cheap IR / laser thermometer from ebay helped confirm the temperature wasn't too high at the heat exchanger outlet, I recommend trying one.
The other thing to consider was that the problem I saw, manifested on cold, calm, damp days when any condensation becomes more apparent.

Good luck.
 
Hi Jon,
I would simply say, because your at full throttle the exhaust gasses are hotter, therefore boiling off a lot more of the water as it passes down the exhaust pipe. With the coolant level not changing it’s nothing to be concerned about.
 
Bobc said:
Are you sure that it's white smoke and not steam?
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My first thought too. Steam will fade as it moves away, smoke doesn't, though it will thin out.

A bit of steam at full throttle is nothing to worry about, provided there's plenty of water coming out too. I'd expect it to be worse on cool damp days.

White smoke is usually unburnt diesel, which could be due to a leaky injector or incorrect timing. There are other causes - expensive ones, but I wouldn't expect to find it only at full throttle, and I wouldn't expect the engine to start and run well otherwise.

My money's on it being steam, especially at this time of year.
 
Stemar said:
My first thought too. Steam will fade as it moves away, smoke doesn't, though it will thin out.

A bit of steam at full throttle is nothing to worry about, provided there's plenty of water coming out too. I'd expect it to be worse on cool damp days.

White smoke is usually unburnt diesel, which could be due to a leaky injector or incorrect timing. There are other causes - expensive ones, but I wouldn't expect to find it only at full throttle, and I wouldn't expect the engine to start and run well otherwise.

My money's on it being steam, especially at this time of year.
Click to expand...
I was called up on the VHF once in the autumn by a concerned yacht following us out of the Orwell... they were worried about the amount of 'smoke' we were emitting.. I had to reassure them that a direct cooled Bukh always emitted a certain amount of steam on a misty morning (nice of them to call us up though).
 
rollover said:
With the coolant level not changing it’s nothing to be concerned about.
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Worth checking your raw water cooling flow - I’ve had steam at higher revs when sea water intake was partly blocked. Not enough to make engine actually overheat but enough that the exhaust temperature was noticeably very warm.
 
Being a pedant today 😀

Remarkable how many can see steam!

It's water vapour that you can see.

I think the experts have covered the reasons.
Low Exhaust Temp seems to be the main issue. Your engine is pushing far more water through the unrestricted elbow.

Don't you hate it when you think you have done a good job and there is indication of another problem!
 
Thanks everyone. Plenty to consider there. Think I’ll get an infra red thermometer and see if there are any abnormal hot spots in the cooling system as a starting point.
I’m not sure if it’s steam or smoke to be honest. Anyway, engine is running and starting very well so maybe I’m just being a bit fussy. But I plan to follow this up anyway.
 
TSB240 said:
Being a pedant today 😀

Remarkable how many can see steam!

It's water vapour that you can see.

I think the experts have covered the reasons.
Low Exhaust Temp seems to be the main issue. Your engine is pushing far more water through the unrestricted elbow.

Don't you hate it when you think you have done a good job and there is indication of another problem!
Click to expand...
Sorry to be a double pedant .

Water vapour is invisible.

What most people call steam is the mist of water droplets caused when water vapour condenses.

This may not be the scientific or dictionary definition but it is the common usage!
 
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