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Hi everyone
Advice needed please. I have a 1998 W reg t4 2.5 TDI. I had the engine replaced with a reconditioned one after the water pump failed and destroyed the original engine. The fuel pump and injectors form the old engine were fitted to the new reconditioned engine. This is where the smoking problem started, a local diesel specialist said it was the injectors but failed to come up with a solution after having a brief look. The reconditioned engine has used a lot of oil since it was fitted so I'm worried that the smoke is in fact burnt oil escaping through poorly matched piston guides and valves but nobody has been able to shed any light on this or really answer the question categorically of what is causing this smoke. So my question to this knowlegable forum and its members is what is causing this smoke, how do I fix it, whos the best person/garage/workshop to fix it and how much would the problem(s) cost to fix? I've already been told £800 for new injectors will fix then problem but as I mentioned earlier I'm worried about the amount of oil the engine uses and the fact that this might be contributing the to smoke, (all of which is coming out of the exhaust btw!) Thanks in advance for any help! :)
 

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It's quite normal to burn excessive oil on a newly recon engine. Which oil did you put in? Mineral based will be best for the 1st 1000 miles to bed in the new components. If you use fully synthetic you will be running her in for the next 40,000 miles. :D
Engine oil & excessive diesel smoke smell completely different the latter is quite pungent on the nose especially if white smoke. (worn Injectors not atomising correctly) Black & sooty smoke is again worn injectors but are throwing too much in.
Oil gives off a blueish/ black smoke that smells relatively sweet compared to diesel.
 

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Discussion Starter #3
Thanks for the reply! I've had the recon engine since 2012 and have done 56K miles. I do about 8K miles annually and use 3x5l of oil annually! The smoke is a mixture of what you describe for oil & diesel injectors becoming more like the description of just oil once engines fully warmed up.lots of blue/gray smoke on startup reducing to less visible grey smoke once warmed up. My local mechanic who services mine annually thinks the injectors need replacing but they were fine in the old broken engine that they were taken out of and never smoked at all!? Could really do with a proper diagnosis of what's actually happening. Are there any top notch specialists in the country who know these engines inside out who could take a look for me? I'm also wondering if I should just try doing an oil change with fully mineral oil instead of the semi-synthetic I've been using to top up with (and presumable service with, although I've no idea exactly what type of oil my mechanic puts in when he services my t4!) Thanks in advance for any more advice! :)
 

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The first thing I'd check is the grade of oil. Go for a semi synthetic 10w40 especially in warm weather. STP also do a cheap diesel engine oil additive that helps if you are burning oil. It's really thick stuff & been out for decades, it will also quieten the engine a bit . Check amazon or Halfords for that.
The grey smoke suggests dirty injectors which may be helped with a diesel additive. Look for one called Rhino diesel, it will help a lot.
If you need new injectors there is a chap on here called Rake, also it'll be much cheaper to go to a diesel injector specialist to have yours reconditioned than the price your guy quoted.
 

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A proper diesel injection specialist will be able to remove the injectors and test them for performance one way or the other .If necessary they may be able to recon them .This is in a job for the guessing ordinary garage .
 
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