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Exhaust Smoke


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Just got my 1995 Defender 300Tdi back on Saturday, 21-Jan-2023, after having the Head skimmed by Westward Precision Engineering (Ireland)and Head Gasket replaced with new by my mechanic.

Initial start-up was clear. However, a short 20 mile journey yesterday (Sunday) and the smoke returned in spades.

Unfortunately the short video I had hoped to post is just a tad too large to post here at 25MB but I took another shorter one which is attached.

The smoke is substantially worse once revved up and is quite similar before the recent repairs.

I don't have an issue with the work that was done as I knew there was a H/G water loss, but it is disappointing that the smoking has not stopped.

My mechanic felt that there was no appreciable wear in the bores, so, what now? 

Appreciate all thoughts on this.

Ron.

 

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The smoke looks blue and it sounds like it's ticking over uneven/on three cylinders.

Does it smell of unburnt diesel? Crack each injector pipe at the injector while ticking over to see if one makes little difference. 

If it is on three this could be a tight valve clearance or possibly a bent con-rod due to coolant in a combustion chamber which I've seen on 300 Tdi's

Steve

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A big Thank You to Bowie69, Eightpot and steve b for your replies.

Your comments and suggestions are much appreciated, however, as I have left the Landy back to the mechanic for him to sort out, I cannot now do the tests you have suggested.

As the smoke initially was really bad, I decided to travel via back-roads, but strangely, at times, the smoke stopped for a while but then restarted... and went away again... and so on, over about 15 miles.

And, of course, when I arrived at mechanic's garage, there was little, or no, smoke while it ticked over for nearly a half hour. Sod's Law. But, I had taken some more videos and was able to show him what had happened en route.

I'm wondering if a stiff, or stuck, Wastegate might cause the on/off smoke? Am not sure, but the Turbo could be original to build date of 1994. Thoughts?

 

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Definitely doesn't sound like it is running right to me. As others have said, it could be a valve clearance issue. Your mechanic should take the rocker cover off and visually inspect that all the pushrods are located correctly on the corresponding rocker and the gaps between the rocker and valve are adjusted correctly. If that checks out okay, then remove each push rod in order and check that none are bent by rolling on a flat surface. If this checks out fine, it could be a timing issue. If the injection timing is not quite right, you will get rough running and unburnt diesel which manifests as white smoke that stings your eyes and smells of diesel fuel rather than diesel exhaust smoke. I know Tdi engines sound like a bag of pebbles in a washing machine, but I am surprised a garage handed it back sounding like that. 

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If it is intermittent then it's unlikely to be any of my first post idea's. 

Maybe a crack in the head between combustion chamber and coolant? 

A sniff(chemical kit) test of the coolant could be in order

Steve

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More thanks to Monkie and steve b for your contributions.

I had a short telecon with the mechanic today. He says the Turbo is leaking oil and that he will source a replacement. Waiting now to hear back from him.

Will report back here once I have an update.

Cheers,

Ron.

 

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12 hours ago, monkie said:

That would explain a smokey exhaust (blue/grey), but I don't understand how that would account for a rough idle. 

Mucking up the mixture 'cos the oil burns as well so it's too rich? Doesn't matter at wider throttle openings because the proportion of oil to fuel is too small to matter...

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Valve guides worn, valve seals worn, valve/s worn, burnt valve seat/s, piston rings worn, cylinder sleeve/s worn....etc, etc

Depends what the mechanic did. Did he whip the head off, skim it and put it back on again? (Half arsed job)
Or did he strip the head, replace the valve seals, regrind the valves, check the guides and seats, check the cylinder walls spec. It sounds like he did the minimum.
 

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