Puff of blue smoke on startup???
 

Hello All.

As title, happens when car is left overnight, big cloud last's about 5 second's, only mod's are a panel filter & centre decat, my99.

Thanks in advance:thumb:

Could be heads passing a little or turbo seals letting by best get it checked

I would probably say it's turbo related.

A puff of white smoke on start up is usually valve stem seals so I would imagine it being that but I may be wrong.

White smoke: White smoke is caused by water and or antifreeze entering the cylinder, and the engine trying to burn it with the fuel. The white smoke is steam. There are special gaskets (head gaskets are the primary gaskets) that keep the antifreeze from entering the cylinder area. The cylinder is where the fuel and air mixture are being compressed and burned. Any amount of antifreeze that enters this area will produce a white steam that will be present at the tailpipe area.

If white smoke is present, check to see if the proper amount of antifreeze is inside the radiator and the overflow bottle. Also check to see if antifreeze has contaminated the engine oil. You can look at the engine oil dipstick, or look at the under side of the engine oil filler cap. If the oil is contaminated with antifreeze, it will have the appearance of a chocolate milkshake. Do not start the engine if the oil is contaminated with antifreeze, as serious internal engine damage can result.

How did antifreeze get in the oil or cylinder in the first place? The engine probably overheated and a head gasket failed due to excessive heat, thus allowing antifreeze to enter the cylinder (Where it is not meant to be).

Blue Smoke: Blue smoke is caused by engine oil entering the cylinder area and being burned along with the fuel air mixture. As with the white smoke, just a small drop of oil leaking into the cylinder can produce blue smoke out the tailpipe. Blue smoke is more likely in older or higher mileage vehicles than newer cars with fewer miles.

How did the engine oil get inside the cylinder in the first place? The car has many seals, gaskets, and O-rings that are designed to keep the engine oil from entering the cylinder, and one of them has failed. If too much oil leaks into the cylinder and fouls the spark plug, it will cause a misfire (engine miss) in that cylinder, and the spark plug will have to be replaced or cleaned of the oil. Using thicker weight engine oil or an oil additive designed to reduce oil leaks might help reduce the amount of oil leaking into the cylinder.

Black Smoke: Black smoke is caused by excess fuel that has entered the cylinder area and cannot be burned completely. Another term for excess fuel is "running rich." Poor fuel mileage is also a common complaint when black smoke comes out of the tailpipe. Black smoke out the tailpipe is the least cause for alarm. Excess fuel will usually effect engine performance, reduce fuel economy, and produce a fuel odour.

How did the fuel get into the cylinder in the first place? Some of the causes of excess fuel are a carburettor that is out of adjustment, a faulty fuel pump, a leaky fuel injector, or a faulty engine computer or computer sensor. If black smoke is present, check the engine oil as in the white smoke example to make sure excess fuel has not contaminated it. Do not start the engine if a heavy, raw fuel smell can be detected in the engine oil. Call your mechanic and advise him of what you have found.

Saying that, a puff of white smoke on start up (if cold) is fairly normal, as moisture resides in the exhaust until it warms up, and the warming up process will convert this moisture into water vapour (steam)

It definately looked blue, thanks for the advice chap's.

turbo.......

Have you topped up with oil recently? Could be too much oil?

Check the turbo by allowing the car to idle for 10 mins then rev to 3k. If you have a cloud of grey / blue smoke then the turbo seals are shot. Blue smoke at start up is more indicative of valve stem oil seals leaking than a shot turbo. Does the car smoke having been driven for a while?

suspect valve seals ?

Yep - agrere with above.
Blue on start-up - valve stem seals
Blue on boost - turbo
Blue on overrun - piston rings

So are valve stem seals a big fix (excuse my ignorance, I don't know a great deal about engines) as I have the same problem on my 2002 WRX?

Thread resurrection!

I currently have this on my Subaru. If it is valve stem seals how much are you looking at to have it fixed? Thanks

Replacing valve stem seals requires removing heads (most think that taking engine out first is easiest). At the very least, you'll then need to take out all the valves and then put in new seals and the refit heads (new head gaskets). In the process you might want to replace cam belt, idlers and tensioner and maybe water pump. Cost? £3-400 if you do it all yourself, £1-2000 if done professionally.

Doubt it's the stem seals, your guides are horizontal on a scoob not vertical as on other engines. If oil was coming past the guides it would smoke worse on overrun when vacuum would pull oil through the guides. Most likely to be turbo, rings, or a breather issue. How bad is it & how often does it happen is it only on cold starting?

Speaking with several specialists it seems a little blue smoke on start up is considered normal on boxer engines as oil remains in the cylinders and at rest doesn't drain down as with other engine types. Great clouds of it are probably not good news though!

I've read the same too. Admittedly mine doesn't do it but as far as I know my engine is on standard internals.

i always get a bit of white smoke on cold start and a bit of black/brown spitting untill warmed up ;)

Blue isnt a good sign though!

I didn't think mine did until it was started by someone else when I was at the rear of the car. It's a barely visible puff of blue smoke which lasts a couple of seconds but is not visible from the driver's seat. I guess if you can see great clouds from the cabin then it's likely something is not right!

Fair point, I've never been behind my car when it's being started!

hi
I am currently having a similar issue with my04 blobeye and removed turbo to find no play in the shaft at all but there was a little oil on intake manifold inner edges and on the exhaust out on the turbo?
did you ever resoleve your problem and figure out the cause as im a little lost now. am doing a compression test in the next couple of days so hope fully that may help however I believe the rings can still maintain a seal if they are worn ?
thanks

Hi mate

Yeah was literally oil being pulled through the inlet. Had a compression test done and everything was ok. If I was you I would take the intercooler off and empty it. It's probably full of oil and needs draining

cheers I will look into that

This happens a lot on the Impreza's.
Every morning blue smoke on cold start up.
Its because there maybe slightly too much oil in the engine due to the dip sticks not being very accurate.

Due to the flat 4 design the crank case breathers are very low. Hence when there's to much oil in the system it easily gets into the breather system then into the intake and coats your intercooler with oil.
When you leave your car over night the oil will drain down out of your intercooler into a puddle next to your throttle body valve, so when you start your engine it gets drawn in and you get a big puff of blue smoke out of the back.

If you have been topping up your oil lately and now there's blue smoke it's probably due to this.

Remove your intercooler and see if there's puddle of oil where it attaches to the throttle body.

Clean the intercooler out by spraying brake cleaner into it to remove all the oil then let it stand till it's totally dry.

Also clean out the opening to your throttle body as this will be covered in oil.

Then remove your oil filter and engine oil and replace with the correct amount oil! Don't go off the dip stick measure the oil before you put it in.

Then after running the engine for a bit switch off let the oil settle.
Then make a mark on the dip stick where the correct amount is.
I bet it will be near to min.

Just for reference valve stem seals don't tend to smoke on start up on a boxer engine that's more of a trait of a conventional inline engine.
Oil doesn't sit above the valves while the engine is off in a flat 4.

They usually smoke when you let off the accelerator.

Turbo seals will smoke when the engine has been idling for a while or under hard throttle.

If the smoke is only happening on cold start up then oil level is your problem.

Rings Turbos and valve seals will smoke while driving.