26 replies to this topic

[bottledfish]

Hi everyone,

just done a full service on my mpi mini, but it appears to be puffing out small amount of white smoke from the exhaust whilst driving. Its not enough smoke for me to notice through the rear window or in any of the mirrors but when i took it on a drive yesterday for about 20 mins or so, a friend who was driving behind me said there is a very small amount of white smoke that comes out the exhaust, and seems to be when i accelerate maybe. Should i be worried? or is it quite normal for such a small amount to puff out the exhaust?

 

James

[Carlos W]

Is it only when the engine's cold, or all the time? 

 

Is it using any water or oil?

[spiguy]

Is your brake fluid level dropping over time? There is a route for brake fluid into the engine, via the brake servo and the vacuum hose which operates the servo as it is connected to the inlet manifold to get it's vacuum.

Edited by spiguy, 12 June 2015 - 11:13 AM.

[bottledfish]

Thanks for the replies, i will check the oil, and brake fluid level if it stops raining today and let you know. Using water, as in coolant level dropping? I will check that too.
I sometimes get visible white smoke when starting engine from cold, which I thought was quite normal. But this is during a drive of about 20-25 mins, so I reckon engine should have warmed. Now she tells me it looked more like a small white vapour, instead of actual smoke apparently. Does that make a difference?

[bottledfish]

Hi guys,

Checked levels over weekend, water/coolant level is normal, brake level looks ok, but oil level has dropped. I do have a slight oil leak but nothing major. I can see the small amount of smoke whilst the engine is idling and I stand behind the car, will take a picture and show you. I assume it's burning oil, but why?

[Carlos W]

Hi guys,

Checked levels over weekend, water/coolant level is normal, brake level looks ok, but oil level has dropped. I do have a slight oil leak but nothing major. I can see the small amount of smoke whilst the engine is idling and I stand behind the car, will take a picture and show you. I assume it's burning oil, but why?

 

Worn valve guides, worn rings. 

 

If you back off, say going down a hill, then give it lots of loud pedal do you get smoke? Does the smoke look blue?

[Carlos W]

Also, you're driving a 14 year old car, with an engine designed in the middle of last century how much oil is it using?

 

Expect it to use a bit

[bottledfish]

Hi Carlos, thanks for the reply

 

how difficult is it to check if its valve guides, or worn rings? and is it a particularly tricky job to replace?

i havent noticed any smoke after going down any hills, to be honest i cant actually notice it all when driving its so minor. i have attached a video to show you the extent of the smoke that is seen whilst driving (although this was actually in idle at the time)  exhaust.wmv   1.08MB   27 downloads .The smoke doesnt look blue to me, what does it mean if its blue?

I wouldnt have said its losing loads of oil, seems to drop to about halfway on the dipstick and hang around there dropping very slowly after that.

[bottledfish]

i dont know if it would make a difference but i dont have a catalytic converter fitted currently

[spiguy]

Black smoke = poorly burned fuel (eg over rich mixture). Blue smoke = burned oil. White smoke = either water - can be normal in the form of condensation such as on a cold day or when the exhaust it cool such as in warm up stages, or could be leaking head gasket, or white smoke also results from burning brake fluid which can get into the engine via the brake servo.

[bottledfish]

cheers for the reply, its not black smoke, and i am pretty sure its not blue (would it be a very obvious blue colour?). hopefully its just condensation, will take it on a long run over the weekend and see if it is still blowing smoke after that. If it were the head gasket leaking would there not be loads of smoke blasting out the back? will also double check the brake fluid level, i am pretty sure it hasnt gone down but better safe than sorry. if brake fluid is leaking into the engine, could it have done any damage? or it is simply being chucked back out the exhaust?

[spiguy]

if you have been doing alot of short runs it could just be excess moisture being driven off. Is there any emulsion / gunk on the underside of the oil filler cap?  Best thing you can do is take it for a good long run and re-assess.

 

Burning a little bit of brake fluid should not do any harm IMO, though the cause would be better off being rectified (if it was that) as it would mean leaking seals in the braking system which is not ideal. I don't think it is that anyway, I watched your video and it looks like water vapour to me. Even just a cold exhaust can cause that as it is a long metal pipe which will cool the gasses as they travel along it such that the water in the exhaust gas condenses.

 

Getting everything nice and hot and a long drive should give you a  better idea of what is going on.

Edited by spiguy, 17 June 2015 - 12:34 PM.

[bottledfish]

Hi everyone, take the mini on a long drive i certainly did, all the way from Brighton to North Devon, approximately 450miles there and back (not in one go thankfully) and the mini worked fanastically well! despite everyone i spoke to saying 'really? your driving the mini down there, are you sure..?' and as you suspected, it must have been water vapour as there was no white smoke coming from the exhaust when we arrived in devon or when we left 5 days later so fingers crossed all is well :). apart from a water leak dripping from behind the facia now, but thats for another day....

thanks again!

[spiguy]

excellent! Always nice when something you thought was a problem turns out to be OK

[Elwyn]

Is your brake fluid level dropping over time? There is a route for brake fluid into the engine, via the brake servo and the vacuum hose which operates the servo as it is connected to the inlet manifold to get it's vacuum.