Smoke from the exhaust and rattle from engine

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Hi Group,

I have just started to have a problem with my Hyundai Atoz 1.0 litre petrol engine just under 70k miles on the clock

The first instance was yesterday when just pulling onto the motorway and
accelerating to overtake a lorry there was a cloud of smoke
from the exhaust and I thought a momentary loss of power.
I eased back and then the engine seemed to run ok for the rest of the 30 mile journey.

Second instance today was pulling off the motorway and doing a right turn around a roundabout pulling tighter and accelerating again this time smoke from the exhaust and a distinct rattle from the engine straightening up
off the roundabout and easing back a little the engine returned to normal.

I checked the filler cap and did notice a little white residue but have seen worse on other cars I've owned. The car isn't using any water and no oil more than a small amount.

Is this the first signs of the head gasket going or some other problem?
 
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Have you checked the oil level? If its low it could be the bearings rattling or if its overfull it could be drawing oil in and burning it.

Peter
 
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I'm puzzled as to what is causing intermittent knocking. If it only happens when you are cornering/braking it would seem to suggest that its when the oil is moving to one side/end of the sump. An odd one that. I expect John will be along shortly, he may have some ideas.

Peter
 
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I tried it again today and sure enough hard right around the roundabout
and rattle from engine and blue smoke. Definitely oil me thinks.
Strangely I tried it again on the next roundabout but nothing that time.

I am wondering about valve stem seals.

I think I will take the plugs out and have a look at their condition to
see if there are any traces of oil being burnt.
 
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A few random thoughts. I'm puzzled too at what would cause an intermittent rattle.
Has the car had regular services with oil / filter change?
Has the car been run with the oil too low at any time?
Is the oil pressure light flickering when the rattle occurs?
-If it is I'd guess it's bad news!
Has the engine been overheated at any time. Low coolant and / or broken belt and then driven?
Smoke, when backed off and then accelerating could be worn valve guides or bad valve seals, doubt if it'd cause a rattle.
Rattles could be:
As already said engine starved of oil. With a modern engine I'd have thought that was bad news.
Hydraulic tappets not getting oil.
Big end bearings. (Usually knock more on load)
Crankshaft thrust bearings. (unlikely I'd have thought, but can knock when clutch depressed if totally shot)
Engine mount broken and engine moving over when cornering hard causing something rotating to touch / rattle.
Are you sure it's the engine and not a CV joint knocking when loaded with the steering turned? Try driving slowly on full lock and see if it knocks then.
 
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A few random thoughts. I'm puzzled too at what would cause an intermittent rattle.
Has the car had regular services with oil / filter change?
Has the car been run with the oil too low at any time?
Is the oil pressure light flickering when the rattle occurs?
-If it is I'd guess it's bad news!
Has the engine been overheated at any time. Low coolant and / or broken belt and then driven?
Smoke, when backed off and then accelerating could be worn valve guides or bad valve seals, doubt if it'd cause a rattle.
Rattles could be:
As already said engine starved of oil. With a modern engine I'd have thought that was bad news.
Hydraulic tappets not getting oil.
Big end bearings. (Usually knock more on load)
Crankshaft thrust bearings. (unlikely I'd have thought, but can knock when clutch depressed if totally shot)
Engine mount broken and engine moving over when cornering hard causing something rotating to touch / rattle.
Are you sure it's the engine and not a CV joint knocking when loaded with the steering turned? Try driving slowly on full lock and see if it knocks then.

No engine has been running perfectly up until now.
I can't say on the engines treatment before I got it as I've owned it about 8 months. But I have done about 10-15k on it and serviced with oil change etc. The condition of the oil looked pretty good when I got it. Engine oil light isn't coming on at any time and engine temperature is spot on.
I think the engine rattle is more caused by the poor combustion when the engine is producing the smoke. Otherwise the engine runs sweet.
Definitely not a CV joint this is engine as it matches the engine speed.
 
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If you're getting a misfire (sorry I missed that) then it could well be that if it's running OK apart from that. In my experience, engines with shot bearings tend to be generally worn out, and feel tired, use oil are generally noisy etc.

Just another thought. Again probably unlikely, but how much fuel do you have in the tank? Some cars can miss from fuel starvation on hard cornering if the fuel gets too low.
 
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Hell, this sounds like something from the days of the three bearing crank :eek:
It sure sounds like oil starvation but the oil lamp would flicker if the oil pressure is failing.....presumably the lamp lights up with the ignition on only?Chuffs of smoke usually indicate over filled sumps, too.
Valve stem oil seals....well, they just allow oil to drip into the cylinders overnight.....indicated by oil smoke on the first start up of the day.
Theoretically, engines can't pink these days either!
Scratching head a bit!
John :)
 
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Could be stem seals as it only did it the first time around the aroundabout.
second time around it didn't do it.
I'll have to do some more experimentation to see what happens.

Hell, this sounds like something from the days of the three bearing crank :eek:
It sure sounds like oil starvation but the oil lamp would flicker if the oil pressure is failing.....presumably the lamp lights up with the ignition on only?Chuffs of smoke usually indicate over filled sumps, too.
Valve stem oil seals....well, they just allow oil to drip into the cylinders overnight.....indicated by oil smoke on the first start up of the day.
Theoretically, engines can't pink these days either!
Scratching head a bit!
John :)
 
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Not very happy about this one.... :(
Do you have a compression tester, by any chance?
Seriously I don't think it's the valve stem seals, as once the oil that's leaked through is burnt, that's it. There's plenty of oil up there but not much will come down with the motor running.
70k miles isn't much, if it's been cared for.
I repaired a Focus with one cracked piston years ago, but that had been to the moon and back.
John :)
 
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Yes I have a compression tester somewhere.
I expect overnight if oil has slipped into the cylinder.
it should have high compression.
Strange it isn't burning on startup though.

Not very happy about this one.... :(
Do you have a compression tester, by any chance?
Seriously I don't think it's the valve stem seals, as once the oil that's leaked through is burnt, that's it. There's plenty of oil up there but not much will come down with the motor running.
70k miles isn't much, if it's been cared for.
I repaired a Focus with one cracked piston years ago, but that had been to the moon and back.
John :)
 
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What colour is the smoke?
Would you have excessive end float in the crankshaft I wonder? Does it ever happen when you apply the clutch fully to the floor?
Are you loosing coolant and or oil on the level marks?

Also consider timing issues, either ignition (time of spark) or valve.
 
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What colour is the smoke?
Would you have excessive end float in the crankshaft I wonder? Does it ever happen when you apply the clutch fully to the floor?
Are you loosing coolant and or oil on the level marks?

Also consider timing issues, either ignition (time of spark) or valve.

Smoke definitely has a blue look to it.
Not loosing any coolant I will keep an eye on the oil as I think it is
probably burning oil. It is an automatic so have no clutch.
Seems strange only going on tight right bends sometimes.
 
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