all of a sudden - blue smoke in exhaust after idling

robsons · Post by **robsons** » 18 Jan 2006, 00:08

OK my car has been absolutely fine (TD Volcane 100K) except the usual trailing arms thing, but within 500miles of a my first garage oil change (I usually do it myself every 5000 miles and use fully syn) my car started smoking.... badly! I was stuck in a queue for an hour stop start stop etc and I looked behind and saw some smoke. Thought which unsocialable bugger is driving that..... and when I pulled away it was me!!

There was slight smoke at idle then absolutely tones pulling away (and yes there was blue in it. Temp guage fine, coolant fine and car running fine. So I got home, pulled off the turbo inlet to the intercooler and gave it some welly. Still some smoke from the exhaust. Smell of oil fumes from Turbo outlet but no fresh oil - just a faint tinge of old stuff in the pipes (pretty perfect really).... So put pipe back on and wellied it. Tons of blue smoke again.

Then on way home it just stopped - no smoke - none!

Went out one evening on my "private test track" to get some shopping and still no smoke. The car pulled cleanly to the end of the speedo and no smoke at all. Now the weird thing is if I leave it idling anywhere (like I did topping up the tyres) when I rev it I get the blue smoke (albeit a tiny bit)...

OK something is wrong but what?
Can't be the rings ....... can it?

Help???? Ideas anyone (and how to check conclusively)

Post by **Peter.N.** » 18 Jan 2006, 09:22

If its fresh oil you can smell, it could be that you have a leak onto the exhaust manifold / turbo and its burning off when it gets hot. If its definitly coming from the exhaust it could be several things, the most obvious being that they have overfilled it, so much for the simple things. Oil accumulating at idle is generally caused by worn valve guides, it could also be bore wear or the turbo seals failing, but I wouldn't imagine that they would come on suddenly, so check the cheapest things first!

robsons · Post by **robsons** » 18 Jan 2006, 13:13

Unfortunately it's not overfilled - in fact it's going down

could it be the oil is too thin?
Although I usually use Magnetec syn and have had no probs. Must admit it looks quite thin on the dipstick

Post by **Peter.N.** » 18 Jan 2006, 13:57

It all looks pretty thin when its hot, do you know what the grade was? Does it smoke when you start it up, or only when left ticking over?

jeremy · Post by **jeremy** » 18 Jan 2006, 14:07

If it was bore wear I think it likely that the engine would leak oil from everywhere as there would probably be considerable blowby - so if you removed the filler cap with the engine running you would have to step back - yes that bad - not just a small flow.

A possibility is that some part of the breather pipe system has blocked over the years and sometimes the crankcase pressurises and forces oil up past the rings.

Another posibility is valve stem seals - early XUD's have bronze guides and no seals - later ones have them but I'm not sure of the change over date. Problems are not common but they could allow oil down the valve guides - either into the engine - for the inlets, or into the exhaust manifold. On petrol engines the tendancy is for the oil to get sucked down the stems when the throttle is shut - producing a puff or cloud of blue smoke on acceleration. I suppose turbo pressure might slow the flow and there is no suction.

Valve stem seals may be replaceable in situ - by feeding some thin rope into the bore through the glowplug hole to hold the valve while the seal is replaced. In any event there is only a tiny clearance betweeen the valve and the piston.

jeremy

AndersDK · Post by **AndersDK** » 18 Jan 2006, 14:36

Blue smoke would be burnt engine oil - right ?
Oil can not burn down the exhauts - instead it will evapourate to a whitish/bluish smoke.

IMO the symptom tells that engine oil is getting into the engine in the combustion cycle for any reason. And then my first thought would be the oil fume / filter ducts for the intake.

If the turbo is suspected - then simply bypass it by disconnecting adequate ducting. The engine will of course be gutless but still be able to drive the car.

Kowalski · Post by **Kowalski** » 18 Jan 2006, 16:45

You should be careful with this one, XUDs are known to be able to run on their own engine oil if it gets into the inlet tract. If enough oil gets in there, it'll rev up until it either damages itself or runs out of oil, the throttle pedal will have no effect and you won't have a rev limiter either.

alastair · Post by **alastair** » 18 Jan 2006, 17:12

Been there, done that, engine running on its own oil, scary!!

Was a knackered turbo.
This sounds like thinner oil than you engine is used to to me.

sooty · Post by **sooty** » 18 Jan 2006, 21:19

Allthough it maybe abit noisey, have you tried running it without the turbo OUTLET (boost side) into the inter cooler, to rule out the Turbo. It could be that the oil seal in the turbo has failed.

Meaning let it idle at home then rev it in both cases to prove one or the other.

Good Luck

robsons · Post by **robsons** » 18 Jan 2006, 23:29

seems to be the same without the turbo connected. Intercooler seems clear of oil. My last Xantia used to fill the intercooler over time but never had blue in the exhaust.

I'll pull the "new" oil out soon and ask the garage what they put in it. I did specify I wanted Syn as that's what it's always had but not what grade. I hoped they used their noodle.

It does seem worse after idling and then pulling away which is pointing to the stem seals. Can't see how thin oil would effect these tho. I reckon one of the garage monkeys moved the car with no oil in it and scuffed the rings.

Must admit it does go really well now - effortlessly goes off the speedo and that's with bigger 195 x 55 tyres.

(all the extra oil in the fuel!!!!)

I'll keep you guys up to date and thanks for the feedback.

Stoo

sooty · Post by **sooty** » 19 Jan 2006, 21:23

I might be wrong, but with an open inlet manifold would there not be any vacuum to draw the oil from the inlet valve seals as there would be with a petrol unit with a closed throttle.

Are you sure its oil and not an idle duff injector, dribbling and not spraying as it should. Like unburnt fuel as you see on a cold morning. Lightly coloured blue smoke.

Kowalski · Post by **Kowalski** » 19 Jan 2006, 22:38

sooty wrote:I might be wrong, but with an open inlet manifold would there not be any vacuum to draw the oil from the inlet valve seals as there would be with a petrol unit with a closed throttle.

The XUD TD has no throttle butterfly so the wouldn't be a whole lot of vacuum at the manifold just the resistance of the air filter. It does have a turbo which will provide some (even if very little) boost at idle. I think it is probably very difficult to tell if your valve stem seals are leaking unless you could deliberately block the intake with the turbo off, to get some vacuum.

AndersDK · Post by **AndersDK** » 20 Jan 2006, 09:35

The only thing that can cause such a sudden symptom, is a broken or seized piston ring. There is no gradual wear that will all of a sudden make the engine emit clouds of smoke.

What was last done to the engine before it started to noticeable smoke ? If that was an oil change - suspect the oil. Not the quality - but the grade of the oil.

Many owners seems to believe they know better than the car manufacturer and pay loads to pour in 5W40 - even 0W30 - despite the fact that the engine from factory is specified for 10W40 in cool countries - even 15W40 in temperate climates like UK.

paranoid · Post by **paranoid** » 20 Jan 2006, 23:57

Err this has happened to my Rover 75 CDT still investigating, but it's going to be expensive.

http://www.frenchcarforum.co.uk/forum/v ... hp?t=17308

robsons · Post by **robsons** » 21 Jan 2006, 00:27

AndersDK

Reckon I'd have a case against the garage? Just because I told them to use synthetic. I'd have thought they'd be duty of care to get the correct grade.

Must admit it seems much better at the moment. I do get a bit after idling but NOTHING like before. I'm going to drain the garge stuff next weekend (bye bye £50) and put in my std magnetec and see if it's OK.