Hi

My 1.4 8v, after a long run downhill with no throttle will produce a very thick and embarrassing plume of smoke once you hit the throttle again. Not black smoke, more a light grey. It soon clears after a few yards, and does not occur at any other time, not after standing idling, not after a cold or warm start, not under acceleration. It also uses a lot of oil, so I first thought of the valve oil seals. I have just changed them this weekend but the problem persists (although I cant tell yet if the oil consumption has gone down, too early to tell) The car uses absolutely no coolant, seems fine on fuel consumption and the only other symptom is an unwillingness to rev much above 4k ( a bit sluggish) It starts better than I do, even on the coldest mornings. Its done 68000 miles.

I changed the oil and cambelt at the same time.

MOT is due soon and I'm worried. Any ideas? Thanks

Rings.

With the throttle closed there is a large vacuum in the cylinder due to incomplete cylinder filling.

This will cause oil to be drawn up into the cylinder past the rings.

That's my theory anyway.

Valve guides will also give similar problem, new stem seals won't help if the guides are worn unfortunately.

Even with worn guides fine seals,id expect at least a little smoke on start up. Worth taking the head off and checking these first though - as its coming off anyway if its the rings.

Rings.

With the throttle closed there is a large vacuum in the cylinder due to incomplete cylinder filling.

This will cause oil to be drawn up into the cylinder past the rings.

That's my theory anyway.

x2. Well described. Long/heavy engine braking on flat ground will be the same.

Not just theory but experience too.

Could be on one cylinder,indicating damage to bore/piston or a snapped ring. But it is usually on all four due to excessive mileage or premature wear often caused by bad oil (neglected servicing or excessive temperature running),either by the oil quality itself or blocked oil supply cassette ring. Excessive carbon can interfere too,and every 6n 1.4 I've taken apart has had it.

You can see what cylinders are burning oil by inspecting the spark plugs.

Vic is spot on there, if the valve guides and/or stems are worn, you are wasting your time trying to get away with just stem seals, also you need the valves out to check the wear.

Hi and thanks for all your advice so far, must admit i'm puzzled though, Car has done under 70k and hasn't been neglected, and runs and pulls really well. Still I hope to god it's not rings. Though I've had it a while I've never really worked on this car till last weekend and dont know it well. Not sure I fancy a head off!

It couldn't be an over fuelling/idle valve problem could it ? VAG/COM reports a fault on lambda and another suggestion of dodgy ICV motor.

I'd be really greatfull for any ideas before dragging the head off!

Just another thought. What oil are you using? and are you sure that it isn't overfilled? (alright, I know that's two thoughts!)

Well that thought crossed my mind, (it's not overfilled by the way), but when I serviced it last, which was the first time (the car only does 100 miles a week or so, and though I've had it well over a year I've only serviced it once... I used the recommended 10/40. I was wondering if one of those oils designed for old engines might do the trick. Do they make THAT much difference? anyone ad any experience of them?

10/40 should be fine, just as long as there is no petrol dilution (oil on the dipstick would smell of petrol).

It might just be worth checking the oil separator on the crankcase breather. ( follow the pipe down from the rear of the air cleaner, take off the box that it goes into and give it a good clean out.)

As someone has already said, it's worth taking out the plugs and checking to see if one or more are oily, but do that straight after a run, rather than when it has been left ticking over.

If the plugs are free from oil, try giving it a longish run at high speed (don't break the law mind!) - It won't do it any harm to give it a good hard run anyway, it's often surprising how it clears out an engine.

Let us know how you get on.

Regards.

Hi

My 1.4 8v, after a long run downhill with no throttle will produce a very thick and embarrassing plume of smoke once you hit the throttle again. Not black smoke, more a light grey. It soon clears after a few yards, and does not occur at any other time, not after standing idling, not after a cold or warm start, not under acceleration. It also uses a lot of oil, so I first thought of the valve oil seals. I have just changed them this weekend but the problem persists (although I cant tell yet if the oil consumption has gone down, too early to tell) The car uses absolutely no coolant, seems fine on fuel consumption and the only other symptom is an unwillingness to rev much above 4k ( a bit sluggish) It starts better than I do, even on the coldest mornings. Its done 68000 miles.

I changed the oil and cambelt at the same time.

MOT is due soon and I'm worried. Any ideas? Thanks

Hi Dave, I've got exactly the same problem! 1.6cl petrol but with 108k on the clock.

It's been bugging me for ages (6 months) then learned to 'coast' on downhills and braking so smoke no longer an embarassing problem. The GF hasn't quite got it. This doesn't happen until we've gone about 10 miles so town driving is ok. Done loads research and I think now it's valve guides and seals worn, on just cylinder number 1 (if that's the closest to the distrib cap)

Anyway it's just failed MOT but only on 1st and 2nd fast idle CO being .45% and .6% (max allowed 0.3%) and I'm trying to work out if this is anything to do with oil. Maybe the burning oil has killed the cat and or the lambda..... anyway diagnostics man coming today so will let you know.

BTW I did find a man who'd recon the valve guides and seals for 120 quid. maybe after I pass theMOT!

Hiya and thanks for the info, I'd be really interested to hear what your diagnostic man says, PLEASE let me know!

My car does very little mileage which means I have neglected little things as they crop up, for example

1. Its been stalling on a sudden pull up far ages, most likely just a fouled up idle control motor, but I've been driving it like that for months (it always restarts fine, its just a bit of a pain but I'm so damn busy I just always seem to have something more important to do

2. This smoking problem has been going on for ages but I had to laugh when you said it, I too coast downhills to avoid showing myself up, I live in west yorkshire which is nowt but hills!)

3. I need new front discs

4. The door's going round the bottom

5. Passenger electric window wont drop

All things that need sorting but ah....

Anyway the cam belt's now done ( didnt know it's age so needed doing) and it gave me a chance to check the valve guides. They had very little play so I left them and just replaced the seals, but ABSOLUTELY NO DIFFERENCE. I mean you'd expect them to solve the problem temporarily at least if they were at fault, but no. SO...

I really need to do a compression test and see whats going on, but on such low mileage I'd be very unlucky if it's the rings. To be honest I've never been able to tell the colour of smoke properly, Obviously thick black smoke I can see but just when is grey not blue not white? An emissions check would be useful to but I dont want to spend any more than I have to. But I must add I only noticed the smoking after I serviced it and changed the oil, (I'm not saying it wasnt smoking before, it probably was) and I have no idea what oil was in it before, it's a thought.

Please let me know what your prob turns out to be.

Hiya and thanks for the info, I'd be really interested to hear what your diagnostic man says, PLEASE let me know!

My car does very little mileage which means I have neglected little things as they crop up, for example

1. Its been stalling on a sudden pull up far ages, most likely just a fouled up idle control motor, but I've been driving it like that for months (it always restarts fine, its just a bit of a pain but I'm so damn busy I just always seem to have something more important to do

2. This smoking problem has been going on for ages but I had to laugh when you said it, I too coast downhills to avoid showing myself up, I live in west yorkshire which is nowt but hills!)

3. I need new front discs

4. The door's going round the bottom

5. Passenger electric window wont drop

All things that need sorting but ah....

Anyway the cam belt's now done ( didnt know it's age so needed doing) and it gave me a chance to check the valve guides. They had very little play so I left them and just replaced the seals, but ABSOLUTELY NO DIFFERENCE. I mean you'd expect them to solve the problem temporarily at least if they were at fault, but no. SO...

I really need to do a compression test and see whats going on, but on such low mileage I'd be very unlucky if it's the rings. To be honest I've never been able to tell the colour of smoke properly, Obviously thick black smoke I can see but just when is grey not blue not white? An emissions check would be useful to but I dont want to spend any more than I have to. But I must add I only noticed the smoking after I serviced it and changed the oil, (I'm not saying it wasnt smoking before, it probably was) and I have no idea what oil was in it before, it's a thought.

Please let me know what your prob turns out to be.

Hello Dave... well not good news I'm sure you're not surprised to hear. It's difficult I know to find someone you can trust in this business cos I'm paranoid they're all in cahoots but looks like it's impossible to say whether it's oil control rings or valve guides/seals. In which case it means stripping engine/ or head off which will need skimming? so that's gonna be 200... etc etc,... he recommended getting a used engine... and getting it fitted, so we're talking 300 plus.

Mine's done nearly 110K and I would like to swap engines over myself but aint got the time now as TOH needs every day for work.

I know when I first got the car I didn't keep much of an eye on oil till that dash alarm started going off! then when topping up could't believe how much it needed! , why the hell they can't put some sort of visible reservoir (like with the brake fluid) I don't know, or have an oil warning alarm that sounds before she's dried up!

Anyway, you live and learn!..... looking for sub 70k engine now with free fitting, for Friday! not much to ask ... eh?

Hiya and thanks for the info, I'd be really interested to hear what your diagnostic man says, PLEASE let me know!

My car does very little mileage which means I have neglected little things as they crop up, for example

1. Its been stalling on a sudden pull up far ages, most likely just a fouled up idle control motor, but I've been driving it like that for months (it always restarts fine, its just a bit of a pain but I'm so damn busy I just always seem to have something more important to do

2. This smoking problem has been going on for ages but I had to laugh when you said it, I too coast downhills to avoid showing myself up, I live in west yorkshire which is nowt but hills!)

3. I need new front discs

4. The door's going round the bottom

5. Passenger electric window wont drop

All things that need sorting but ah....

Anyway the cam belt's now done ( didnt know it's age so needed doing) and it gave me a chance to check the valve guides. They had very little play so I left them and just replaced the seals, but ABSOLUTELY NO DIFFERENCE. I mean you'd expect them to solve the problem temporarily at least if they were at fault, but no. SO...

I really need to do a compression test and see whats going on, but on such low mileage I'd be very unlucky if it's the rings. To be honest I've never been able to tell the colour of smoke properly, Obviously thick black smoke I can see but just when is grey not blue not white? An emissions check would be useful to but I dont want to spend any more than I have to. But I must add I only noticed the smoking after I serviced it and changed the oil, (I'm not saying it wasnt smoking before, it probably was) and I have no idea what oil was in it before, it's a thought.

Please let me know what your prob turns out to be.

Hello Dave... well not good news I'm sure you're not surprised to hear. It's difficult I know to find someone you can trust in this business cos I'm paranoid they're all in cahoots but looks like it's impossible to say whether it's oil control rings or valve guides/seals. In which case it means stripping engine/ or head off which will need skimming? so that's gonna be 200... etc etc,... he recommended getting a used engine... and getting it fitted, so we're talking 300 plus.

Mine's done nearly 110K and I would like to swap engines over myself but aint got the time now as TOH needs every day for work.

I know when I first got the car I didn't keep much of an eye on oil till that dash alarm started going off! then when topping up could't believe how much it needed! , why the hell they can't put some sort of visible reservoir (like with the brake fluid) I don't know, or have an oil warning alarm that sounds before she's dried up!

Anyway, you live and learn!..... looking for sub 70k engine now with free fitting, for Friday! not much to ask ... eh?

Oh dear, sorry to hear that. Yeah I too have been caught out on the oil, mainly because I used to check it regularly when I first got the car and it never used a drop so I guess I got complacent, but I'm still convinced that mines an overfuelling problem, when oil burns it has an awful smell and produces thick blue/black smoke mine's a very light colour smoke, I'm gonna check a few things before ripping the engine apart. What colour is your smoke?

Low regular miles are savage on an engine.

If you go out on a cold morning and take the car for a 50 mile drive,you'll do more engine damage in the first five miles than the immediately following 45 miles.

So 100 miles a week? If that's 10x ten mile journeys then you're doing ten times more damage to your engine on average per mile than someone who does the same mileage once a week up the motorway.

Sounds like you run on a cold engine most of the time,meaning heavy mechanical wear,resulting in the symptoms you describe in your first post.

Oh dear, sorry to hear that. Yeah I too have been caught out on the oil, mainly because I used to check it regularly when I first got the car and it never used a drop so I guess I got complacent, but I\'m still convinced that mines an overfuelling problem, when oil burns it has an awful smell and produces thick blue/black smoke mine\'s a very light colour smoke, I\'m gonna check a few things before ripping the engine apart. What colour is your smoke?

Hi Dave, it\'s not really that blue but it\'s definately oil.... you can smell it! and the diagnostics bloke said it was burning oil. Plus it\'s using so much oil it\'s got to be going somewhere... and there\'s no leaks apart from the internal one into the engine.

It did surprise me how he got the engine to smoke whilst in the drive..... he just revved it hard and then totally throttled off and there it was... pouring out... \"you\'ll never get that through the MOT\" he said.... even with a new cat.

He then said there was no way to prove whether it was rings or the head so anything was a risk.... imagine taking the head off getting it done and replacing... only to find it was rings! That would have been 200 down the pan.

Anyway. new engine on the way now. just better be a good one and I\'d better get it in quick, the other half\'s not gonna like getting a taxi to work!

This engine\'s going to be checked for oil every weekend... I\'m not going through this again.

Good luck with yours.

Scrapping it would be an option but I just don\'t like binning stuff that (nearly) works!

Edited 5 November, 201015 yr by cassiewoofer

Woah, dont bin that engine just yet!!!! I've just cured mine!!!!

I've just had my first proper day off and decided to attend to the other faults that I could and first on the list was my bloody annoying idle problem (it used to die when I throttled off at junctions). I got some carb cleaner and cleaned out the butterfly throttle valve with a cloth and finger. It had a fair bit of black gunk around it. Then followed the instructions and sprayed it down the throttle throat a few times with the engine fast idling.

re fitted the air cleaner and took it out for a spin.

Result, no stalling, revs right up to top line again smooth as anything, then I went down the great hill where I know for certain it always embarrasses me and... not a puff of smoke! Absolutely nothing!!!

I can only surmise but I recon the butterfly was maybe not closing properly and the engine management was seeing a still open throttle so was injecting fuel all the time regardless of what my right foot was doing. Then when I went back on the gas all that fuel was going up in smoke! Anyway the problems have all gone just for the cost of a can of carb cleaner, about a fiver!

Surely it's gotta be worth a try, it only took me ten minutes.

Woah, dont bin that engine just yet!!!! I've just cured mine!!!!

I've just had my first proper day off and decided to attend to the other faults that I could and first on the list was my bloody annoying idle problem (it used to die when I throttled off at junctions). I got some carb cleaner and cleaned out the butterfly throttle valve with a cloth and finger. It had a fair bit of black gunk around it. Then followed the instructions and sprayed it down the throttle throat a few times with the engine fast idling.

re fitted the air cleaner and took it out for a spin.

Result, no stalling, revs right up to top line again smooth as anything, then I went down the great hill where I know for certain it always embarrasses me and... not a puff of smoke! Absolutely nothing!!!

I can only surmise but I recon the butterfly was maybe not closing properly and the engine management was seeing a still open throttle so was injecting fuel all the time regardless of what my right foot was doing. Then when I went back on the gas all that fuel was going up in smoke! Anyway the problems have all gone just for the cost of a can of carb cleaner, about a fiver!

Surely it's gotta be worth a try, it only took me ten minutes.

Thanks Dave, I'll give it a go. and let you know.

Keith

i know that this has probably been said somewhere up there ^^ but i used to have a classic mini with an engine build that i did with a freshly bored block with new pistons ect. i had the same probvlem with that and it turned out to be one of the oil control rings that was damaged/faulty and was letting in too much oil. i just got a compression checker and the piston that was faulty gave a higher reading than the others. also could be valve seals.. hope it gets sorted buddy i know its a bit shit when it happens

Update, been running around for a few days now and everything is still clear of smoke and purring like a kitten. The oil consumption seems to have all but stopped so that must have been the valve stem seals. I also know that they will not last forever without changing the valve guides as well and that's for the future, but it shows that even though I was using a fair bit of oil, it wasnt that which caused all the smoke.

I guess it's all to easy tojump to conclusions, I would never have made the connection between a gummed up butterfly and all that smoke. We live and learn!

I hope it solves your problem too Keith.

Can I just add a big thanks to all of you who were kind enough to add your advice, it's just what these forums are all about! Thanks again

Edited 8 November, 201015 yr by davewuff