Hi all, my 1998 XJR has developed a puff of white smoke from the exhaust when started from cold, its only done it since i changed the oil this weekend, should i worry???????????

Its perfect once its started, and starts perfectly as it should 130k on the clock.....

Regards

Chris

 

White is generally water, and it's likely just condensation in the exhaust, which is normal as the weather cools

 

Chris,
Check to see if you are loosing brake fluid from week to week. An obscure problem that causes "white smoke on start up only" is--------a leaky master brake cylinder.
Brake fluid leaks into the vacuum brake booster and is drawn into the engine on start up. The amount is so small while the engine is running that it produces no smoke.

 

Thanks tarhealcracker, i will check that!

Its not water condensation, its oil based i can smell it!

 

Fair enough, that information wasn't given in the first post, and oil in the exhaust tends to have a blueish hue.

 

Its not useing brake fluid......?

 

Is the car supercharged or not. I work on big diesels engines and water causes steam, oil couses blue smoke but to much air can give you white smoke...

Not sure if that helps any..

 

Yes its supercharged, its a pure white dense single puff that hangs in the air, its only out of the drivers side exhaust, im an engineer and im sure its not the normal condensation, its smells of oil......

 

Sounds like the valve guides to me. Do you ever get it at the lights or when you stop for longer periods with the engine running?

 

Fold a paper towel into a smaller square and place it tight over your exhaust tip.Cover the opening of if completely.
Then after you have it covered,hold it as tight against the tip as you can and have a friend start your car and let it run.
Now you have the paper towel over the tip for 10 seconds or more.
Get another paper towel and do this again if you have dual exhaust.

By time I was done writing,I see that you had added more to your post.If it is just the one side and it smells of oil and it is white as you said.I say head gasket fixing to go.
A compression test on that band"side of engine" is a must!!!!!

Report what you see on the paper towel.

As said early on.White is water.This is a normal thing.

That is one reasons why it is bad to drive a car only short trips.
Not letting the engine get to normal operating temp.
Short trips only,are a good way of rusting out the exhaust system to start with.The water will lay in the low spots of your exhaust system and you will see it rusting for the inside out,on lowest corners on the mufflers and converter,etc.
If your job is only 5 minutes down the road,you are doing harm to your car in the long run. If this is the case start your car before work and let it idea for 10-15 minutes in the drive way before you go.
Other may and will have thoughts on this so please clime away....

Blue is oil,leaky rings,valves,head gasket.I have had a intake manifold gasket not seal to the heads before and the engine sucked oil into the intake runners,causing a nice blue trail following me.

If you do not like the suggestion that it is condensation in your high mile engine,how about this bad thought??

A leaking head gasket?
It will darn sure give you a puff or more of white smoke on start up AND running.
If it is not bad as of "yet". It will in a short time make enough white smoke that you will not see your car from it.And the engine will die.A engine can NOT compress water like it does fuel.Water in cylinders will bend valves.

Might want to do a simple compression test on each cylinder.
Seeing as the miles stated on your engine,this would by my best GUESS.c1476eb7-2a27-4edb-945c-2b6fd85f5a74
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Clean paper towel....maybe its just the lump of fuel being put in to get it started. The puff was still there, then what i would call normal exhaust vaper. I odd thing is i saw this for the first time last week after changing the oil.

 

That squirt/spray of fuel that is dumped into each cylinder should be turning to fire from you plug,rather then sending it unburnt unspent,out the exhaust.

Paper towel smell like unspent fuel?Meaning raw fuel/gas.
Will it do this on every start up,or only the first start up of the day?
If it sat for only 5 minutes and then you started it back up,will it do this?
If so how about 2 minutes after shut down and restart?
If yes again,how about if you shut it off and count to 10 and crank it back up?

I am GUESSING that right after shut down and a restart,that it will not do this?
But then after doing this, you park it for the night and that next morning it will again.

You can do this your self.Take one spark plug out at a time and test that cylinder with your compression gauge.It simply screws right in the spark plug hole.Put a dab of oil on the threads of the comp. tool and the spark plug threads when reinstalling them.

Look at that spark plug while you are at it.Do a internet search on spark plug reading and if new to working on or around engines,you will be amazed what that little plug is saying to you.No one seems to listen...
That is how from Top fuel race teams to your local garage guy can tune a engine.But anyways........

If it is not water in the cylinder then can you have fuel entering it after shut down?Starts up easy enough you had said.Not crank crank crank,fire.
And your oil dip stick says the proper oil level still on it and has no smell of fuel or is turning to brown slush.

If all the cylinders check out to be good with a compression gauge.
I think that they should all be within 10-15 lbs. of each other??
BIG ? cause I do not even know what engine we are talking here.
"Should" be able to find a write up on your engine for cylinder compression testing.

Or if your neck tie just seems to get in the way,you can always try injector cleaner in your fuel tank.A simple thing to do.
Add it to a full tank of gas.Or half tank or even quarter tank.It will say the mix ratio on it.A good thing to do anyways.You may find your miles to the gallon going back up!

To you it is a white puff.To a mechanic he may say it is gray or green or blue?If he says green go take it to another shop...

I am guessing that you do a oil change every 3k or with that synthetic "stuff" a bit longer.And you did not change oil weight or brand on your oil change.Engines today have so many seniors that it may even be one of them.But if that was the case.I would think that a light would come on when the system did a once over check.You may have a sensor that has cracked or rusted out and some how because of,it is allowing water to go in a cylinder.That would make you white puff.
You overheat the engine and crack a head?
Could guess forever.Kinda like pick a number or color...

Good luck.


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I'm returning this thread as the topic with the white smoke puff at start up is driving me crazy every morning in the past month.

Two weeks ago I found this thread on the forum and decided to follow the suggestions given by hemitwist. Here is what I found:

1. The smoke is pure white... it's not grey, it's not blue, pink or whatever else color of the rainbow
2. The smoke doesn't have any smell... maybe a little bit smell of unburned fuel but most likely - it's just vapor of water.
3. The white smoke appears only after a long stay (more than 12 hours) and doesn't appear every time! It's not related to weather conditions or to any other case I could figure out meaning that it's completely random.
4. My Jag is running on LPG... first of all - every time I shut the engine off there is a significant amount of gas that is left in the engine (and the exhaust) and maybe it's not burning completely at start up...
5. Second thing about the LPG is that this fuel is producing much more water vapors than the normal petrol (I don't know why) and it's normal to have water drops while running the car... so maybe this is the reason why I have water at start up.

So based on this first 5 points it's seems that this is condensed water in the exhaust system. I was just about to end the issue with this conclusion, but then I asked myself a few things:
1. If this is water why it started appearing just a month ago?! The LPG conversion was done 5 months ago...
2. Why it puffs only from the left exhaust?
3. The last month was the hottest time in Bulgaria EVER... the temperatures never dropped below 30C degree and they even reached 40-42C. It's seems impossible to me that any water could stay in liquid state in the exhaust system on this temperatures...
4. Beside the white smoke puffs I have other issues and I believe that they may be related to the same problem... When the engine is in normal working temperature the idle work of the engine is kind of unstable (SOMETIMES!)... when I stop on a traffic light it seems like someone is having sex on the back seats. Also the car is accelerating very well but when I'm climbing a hill it seems that it has some kind of loss of power even on high RPM.

All this made me check for problems, so here is a list of things I know for sure: I have new cam cover gaskets and seals, spark plugs (NGK), clean air filter, no air leaks between the filter and the throttle body, clean throttle body, the level of coolant and oil is not changing, the engine have never been overheated, the problem is not related in any way to the gearbox... And no faults on diagnostic at all!

The only thing I haven't checked is the compression of the engine... I'm afraid of thinking that this may be the first symptoms of nikasil engine die... But if this is the case - why the car is starting so well? I will check the compression as soon as I have time for it, so can anyone tell my what is the compression I should expect from a 3.2 V8?

So here is the place for my question... "WHY?"... What is wrong with my car I tired of leaving the Jag in "expert garages" and then hearing "there is no problem with the car - take it and drive!"

 

Just have it run on normal fuel for a while, and see how it develops.

 

I forgot to mention it... I tried to run the car for 3-4 days only on premium petrol without switching to LPG - all the symptoms were the same, except that the white smoke was little less.

 

Follow up on this tip. You may have more than one problem. It;s easy to eliminate the brake fluid possibility first.

 

I am not sure if the newer engines are like the older engines I grew up with, but a puff of white smoke at start-up was a sign of slightly worn valve seals. Over the time the car is parked small amounts of oil gradually leak into the cylinder. When started cold, it has had time to leak enough oil to produce the puff, but it does not leak enough to cause smoke while running or a warm restart.
Just something I learned back in the 60's.
Cheers

 

Right now I'm watching the level of the brake fluid as tarhealcracker said earlier.

As for the valve seals and the oil in cylinders... it can't be, because the oil level is still on it's maximum level after almost 10000km... and also - if this was the case then it would puff white smoke every time after a long period of park... and I do have left my Jag for more then a week and it started without any puffs-muffs...

Anyone can help with information about compression on cylinders on 3.2 V8 engine?!