Blue Smoke question

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BigDons

Member
Posts
63
Location
Dunbar, Scotland
Ok guys.

Doscover 2 1999 TD5 144,000 miles.


I have just changed my cylinder head gasket. All seems good. No pressue in coolant etc. No blowback from oil dipstick, or contamination of oil.

Found Intrercooler was blown, so also renwed that,.. and

MAf sensor,
Turbo Hoses,
Coolant temp switch,
Blanked EGR,
Fully cleaned inlet manifold.

then did a service,
Oil Filter,
Air filter etc.

It now has some blue smoke !? Not much, but noticable as I am going along the road.

As I renewed all the turbo hoses, could there still be some oil and crap kicking about somewhere ?

Help ?

Donna x
 
OK - I'll stick my head above the parapit - the classic reason is oil getting into the combustion chamber and there are several possibilities for that (some of which you've seemingly already dealt with) which leaves other - such as a broken piston ring. Worth a compression test perhaps?

Hopefully if this is a `wild answer' others will pipe up!
 
Could be partly combusted diesel, could have a dribbling injector or something like that. I think I'd start by having the injectors tested before investigating more dire engine issues. Is the blue smoke more notable at a specific RPM?
 
Blue smoke is a classical cylinder head issue.. First thing first.. Check oil level. Occasionally over filling oil will do it. If you have taken the head off, you could have damaged valve seats/ Linings. Double check the head gasket, it could have blown if it was not fitted properly and the head skimmed clean. Piston rings is another classic... If you take the head off, have a feel around the cylinders for any marks and signs that your piston rings have gone. If all else fails, If it were me, I would take the head to an engineering company to get tested and re lined...

MudRat
 
blue smoke is burnt oil,which can come from rings /bore but he has no crankcase compression ,valve seats wouldnt give blue smoke ,valve guides would but worse on start up
 
True... Yet again, I stand corrected.. However, I know on my old 90', it chugged blue smoke, admittedly worse on start up but did continue through the journey.. The head was removed.. The rings were fine, but when the head was sent off, they found that the lining and seats were completely shagged. I suspect the valve guides would have been done aswell, but they reconned the block for me and when I refitted it, it was fine after with no smoke! Mind you, I did do a complete overhall at the same time..
 
My 306 tdi smokes blue smoke.

Before I bought it the previous owner had a brand new head fitted after cam belt failure.

I fitted a new thermostat as it had he wrong one in and wouldn't get to temp

The new thermostat warmed it up and the blue smoke was dramatically reduced but still get some when I put my foot down a bit

Pedal to the metal produces black

The engine doesn't use any oil at all

I put it down to reduced compression (worn engine) not burning fuel propper when cold and maybe injector pattern not as it should due to wear and fuel not burning efficiently.

Whatever,,,, it's a banger so staying as it is for now:rolleyes:
 
there are few reasons why skimming is not recommened ,depth of valve head from head face ,this reduces when skimmed and can cause contact between valve and piston(they do run that close),cam be mitigated by pocketing valves,maching seat to sit valve further down,thicker head gasket,on some heads casting between waterways etc not thick enough,once over heated there is a good chance that head will have relaxed and will move again,
 
That is very interesting... I was on an advanced vehicle examiners course a few weeks ago and we had this debate about skimming. One chap was adamant that this was the way forward and had it done to his TD5 90.. I have to say, when my head went, I sent it off the the engineering co.. They reconditioned it for me. I honestly thought that part of the recon process was skimming it. Good grief, my ignorance amazes me.... Thanks for that.. I certainly wont have my latest disco's head skimmed... I assume then that is why so many people who change their head and have it skimmed complain of further head gasket issues!?

Thanks for correcting my ignorance.. Really is appreciated!

MudRat
 
My 306 tdi smokes blue smoke.

Before I bought it the previous owner had a brand new head fitted after cam belt failure.

I fitted a new thermostat as it had he wrong one in and wouldn't get to temp

The new thermostat warmed it up and the blue smoke was dramatically reduced but still get some when I put my foot down a bit

Pedal to the metal produces black


This is now what mines is doing. Has contrant smoke on Idling and when you boot it BLACK.,, I give up :-( What's wrong with it now ?
 
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