White Smoke...

[mobeyone]

All, long time no speak.

Well, thought everything was ok but recently I have noticed my car when starting having a puff of white smoke come out from the rear?

Usually dissapears when at normal temp but I am worried about either loss of coolant or a blown head gasket.

I checked my antifreeze and it was a little low, last time this was checked was when it was replaced last year so I topped up around two weeks ago and it has not moved since so I am not loosing antifreeze.. and I suspect it maybe my headgasket??

Oil looks fine but does need changing, car drives a little rough but a service is due and economy is still ok, just a puff of white smoke in the morning..

is it simply the cold? after driving 5 minutes its gone completely.

tia

[cfc1]

Its just condensation, nothing to worry about, quite normal... to reassure yourself look at other cars on these cold mornings.

[stevepearce]

Hi,

White smoke is caused by one of three things.

Anti freeze into the cylinders.

This can be caused by a number of things - head cracked / warped, head gasket blown or a cracked cylinder.

There are several ways of checking this - you have done one by checking the coolant level.

If this drops then this obiously points to a leak from the system, which is pressurised.

One pointer to this is a missfire when starting from cold.

If you can you can take it to a garage where the can check if there are any Co2 signs in the cooling system, this then points to a pressure leak (from a cylinder). This is done by removing the presure cap from the cooling system - once cool enoughto do so - and run the engine - with the pipe which normally goes up the exhaust - placed in the header tank - *not in the coolant. Should have a ZERO reading.

Another way of checking is by pressurising the system and running the engine - the pressure should not increase greatly - should sit just over 100psi

Brake Fluid into the cylinders.

1st need to check the brake fluid level, if this has dropped, easiest thing to check is the very top of the brake pedal, or under side of the pedal - inside the car. If there is a oily fluid could be brake fluid. This gets into the engine as the fluid has to go via the servo, which in turn is linked to the inlet manifold to obtain a suction, making the servo operate.

Usual sign for this is a run at 50mph +, then take foot off throttle (allowing engine to run on over-run) for about 20 seconds and then re-apply the throttle - checking exhaust for the white smoke.

(This is the same process for checking valve stem oil seals for wear)

** unless a remote servo fitted.

Mix of hot and cold gasses.

as stated by another member - could just be the cold.

Hope this helps

Steve

[Crewchief]

Not saying it is completely impossible but, I have been working on cars for about 28 years and have never got break fluid in the engine, never heard of this happening either.

There is another thing that never got mentioned.

If you have fair few miles on the old girl, even if the head has done in the past even the recent past, they don't always change the Valve guides.

These when they first start to go will only leak a tiny bit of oil when cold when the valves heat up they expand and the smoking stops.

As it gets progressively worse it will smoke longer but may still stop after the engine has run for a while.

tricky thing to this is since the amount of oil getting through is so small the engine may run a little rough but the plugs won't look overly fouled.

Seen this plenty of times.

The down side to this is while it will take a good long time eventually it will ruin the Lambda sensor(s) and Cat as the oil slowly bakes onto the ceramic inside the cat.

This will of course make you fail an MOT and the lambda readings will throw off the ECU.

Lambda sensors are anywhere from £35-85 each and some cars have as many as 4

A new cat or cats run from £90-300 each.

Catch is there is not really a reliable way to tell if the valve guides are going.

They leak such a small amount of oil they may not foul the plugs.

a pressure test will not show this since the valve should be closed when pressurising the cylinder.

Some times you can tell by looking at the guides then self and if there is some carbon build up that can be a symptom.

If the oil slowly goes down frequently, again as an engine runs it breaks down oil and some is burned off naturally and the levels may not be distinguishable.

Check you plugs for oil fouling.

If you are not sure take a clear close up pic of the plug and email it to me, I have seen it enough I might be able to tell.

OK enough of possible bad news.

It is winter and the ground tanks do pick up some condensation so will your fuel tank if it sits for more then a few days at a time.

Try filling up some where different, try topping up at a few places and see if it stops.

Actually check if it is smoke hop out and put you hand near the exhaust feel it coming out does it feel steamy?

A bit nutty idea but it's something old school mechanics like me do smell your hand after a few seconds of having your hand in the steam or smoke.

Does it smell like burnt oil or just plain old exhaust.

If the rings were going it might only smoke at start up until they go completely, this is kinda of easy to sus out the extra crank case pressure will push oil into the PCV or breather check your air cleaner for signs of oil.

Again this should show up on the plugs as oil fouling but not always.

If there is oil in the air filtre and oil fouled plugs it's likely to be the rings.

too much crank case pressure from a plugged PCV

There are actually quite a few reasons some simple some easy to fix some are full engine rebuild or throw away and get a new block.

Do the simple tests first that are free, work into the cheap and easy to fix and by a process of elimination if the the free to sort and cheap to sort things don't work you know it's something worse.

if you get stuck drop me a PM I will help if I can.

[Red Yaris 54]

Have they elected a new Pope? ;)

(Non serious answer introduced because you have received two very good "technical" replies and I thought that my reply might cheer you up ;) )

[wilson210484]

If it is your head gasket have a look at this product Steel Seal.

I have had problems with two Previa's i used Steel Seal head gasket sealer and sure enough my current Previa is still going strong. See http://www.partsforallcars.com it really works!!

[Parts-King]

Not saying it is completely impossible but, I have been working on cars for about 28 years and have never got break fluid in the engine, never heard of this happening either.

This is possible and I have seen it, it's when you have a leak in the brake master cylinder and fluid goes into the brake servo. This fluid is then sucked into the manifold and burnt as "White smoke"

Of course, we are probably talking about two seperate issues here, "White smoke" and "steam or condensation" which are two different issues

My guess would be that if you have no oil in your water, or vice versa, and you are not losing either coolant or brake fluid, then it is probably steam/condensation on these cold mornings

Kingo

[wilson210484]

I must say i have never come across brake fluid finding its way into the engine but i will remember what you have said as unlikely as it seems i guess you never know.

[Parts-King]

I must say i have never come across brake fluid finding its way into the engine but i will remember what you have said as unlikely as it seems i guess you never know.

I have only seen this happen once or twice in over 30 years, but I have seen it for my own eyes, it stinks too when burnt :D: The brake fluid has to be leaking past the servo diaphram so in effect there are two faults in order for this to happen

Kingo

[propnut]

If it is white smoke, clears once the engine is warm, you are not using water and the car is not overheating then it is, as has already been said, condensation. Stop Worrying.

My Previa sets off a white smoke screen when I start it on a cold morning and it is 100% definitely condensation.