White Smoke
#1
White Smoke
Recently bought an '89 XJS, very happy with my ride.
BUT... only to discover clouds of white smoke emitting from the exhaust when I've been driving for a while and the engine is nice and hot. No smoke during start-up.
A few interesting points though...
It would seem as if the smoke comes primarily from the one exhaust only - right side.
Not much smoke either whilst driving/cruising, but especially so when I pull away from a stop street or traffic lights.
Has anyone had similar problems?
Any insight or assistance would be greatly appreciated.
BUT... only to discover clouds of white smoke emitting from the exhaust when I've been driving for a while and the engine is nice and hot. No smoke during start-up.
A few interesting points though...
It would seem as if the smoke comes primarily from the one exhaust only - right side.
Not much smoke either whilst driving/cruising, but especially so when I pull away from a stop street or traffic lights.
Has anyone had similar problems?
Any insight or assistance would be greatly appreciated.
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orangeblossom (02-08-2017)
#3
Hi TWR
You've got an 89 XJS so I'm taking an educated guess by thinking you have a Marelli, though if you have a Lucas Car (That has a small square
black box on the inlet manifold with a Lucas sticker on it) then this will not apply.
In basic terms the V12 engine on a Marelli Car, is like Two Six Cylinder Engines joined together.
And under the right (or should that be wrong) conditions, the 'A' Bank or the 'B' Bank side of the V12 Engine can run on its own.
As in just running on Six Cylinders on one side of the Engine only.
In the event that should happen, the side of the engine that isn't running will be Pumping Raw unburnt Fuel into the Hot Exhaust, which could
result in what is known as a 'Marelli Fire' and while I'm not suggesting that is about to happen.
It could be worth bearing in mind.
Maybe the White Exhaust Smoke could be an early indication of something going wrong in that direction.
If you've only just bought the Car, then its definitely worth checking the 'Spinner in the Dizzy' and if there's any signs of burning then replace it.
In the event your Car decides to Stop unexpectedly, then switch her off as quick as you can and grab a Fire Extinguisher just in case the worst happens.
But on the other side of the Spectrum, it could be what Brad said, so do a check on the dipstick for any signs of water in the Oil.
Or maybe its just Climatic with the prevailing Weather conditions that you have at this time of the year but no real way of knowing, without seeing the Car.
You've got an 89 XJS so I'm taking an educated guess by thinking you have a Marelli, though if you have a Lucas Car (That has a small square
black box on the inlet manifold with a Lucas sticker on it) then this will not apply.
In basic terms the V12 engine on a Marelli Car, is like Two Six Cylinder Engines joined together.
And under the right (or should that be wrong) conditions, the 'A' Bank or the 'B' Bank side of the V12 Engine can run on its own.
As in just running on Six Cylinders on one side of the Engine only.
In the event that should happen, the side of the engine that isn't running will be Pumping Raw unburnt Fuel into the Hot Exhaust, which could
result in what is known as a 'Marelli Fire' and while I'm not suggesting that is about to happen.
It could be worth bearing in mind.
Maybe the White Exhaust Smoke could be an early indication of something going wrong in that direction.
If you've only just bought the Car, then its definitely worth checking the 'Spinner in the Dizzy' and if there's any signs of burning then replace it.
In the event your Car decides to Stop unexpectedly, then switch her off as quick as you can and grab a Fire Extinguisher just in case the worst happens.
But on the other side of the Spectrum, it could be what Brad said, so do a check on the dipstick for any signs of water in the Oil.
Or maybe its just Climatic with the prevailing Weather conditions that you have at this time of the year but no real way of knowing, without seeing the Car.
Last edited by orangeblossom; 02-07-2017 at 06:02 PM.
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TWR Replica (02-08-2017)
#4
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#5
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orangeblossom (02-08-2017)
#6
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orangeblossom (02-08-2017)
#7
Thank you for the feedback guys, appreciate.
Coolant seeping into the cylinder sounds about the most plausible cause, especially after speaking to a UK mechanic who suggested that the auxiliary air valve [situated on the water rail] might be leaking coolant into the intake manifold.
I'm really hoping I dont have a bust head gasket... will have to embark on a process of elimination.
Coolant seeping into the cylinder sounds about the most plausible cause, especially after speaking to a UK mechanic who suggested that the auxiliary air valve [situated on the water rail] might be leaking coolant into the intake manifold.
I'm really hoping I dont have a bust head gasket... will have to embark on a process of elimination.
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#8
Hi TWR
Much more likely to be what Grant said, as he has the kind of in-depth knowledge that mere mortals like myself can only dream about.
He's not called 'The Wizard of Oz' for nothing and so I reckon he has gone and nailed it!
This is the thing that Grant was talking about.
Vacuum inlet manifold on 'A' Bank
Much more likely to be what Grant said, as he has the kind of in-depth knowledge that mere mortals like myself can only dream about.
He's not called 'The Wizard of Oz' for nothing and so I reckon he has gone and nailed it!
This is the thing that Grant was talking about.
Vacuum inlet manifold on 'A' Bank
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#9
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orangeblossom (02-08-2017)
#10
OK,
Many reasons, few theories.
One drop of ATF (Auto Trans Fluid) will produce MUCH smoke, so when the vacuam modulator diaphragm fails, the vacuam of the engine sucks that fluid into the RH inlet manifold.
Car starts to smoke, so owner shuts it down, and there it sits.
That fluid "soaks" into the alloy casting of that manifold.
Years later, one of us types rescues the car, and DRIVES it, alloy gets hot, the fluid is leached out, and mixes with more comong up from the transmission, coz that diaphragm is still broken.
End result, SMOKE.
Same scenario with brake fluid.
I would raise the car, safety PLEASE, coz the Jag will hurt you if it falls, and reach under the RH side, and between the exhaust pipe and the trans case you will see/feel, the modulator. It has a 90deg rubber elbow attached. Pull that elbow, CAREFULLY, and look for RED fluid in the modulator spigot, and/or the elbow. If there is the slightest sign of fluid, the modulator is dead.
It is a standard GM item, nothing special at all.
As for that AAV leaking coolant into the inlet system, NEVER, EVER seen one do that. OK, nothing is impossible, its a machine, but in all my dealings with the V12, NOPE.
Same for head gasket failure, rare in the big scheme of things. However, an overheated engine will cause those gaskets to fail at some time. Dropped valve seat is usually first.
Many reasons, few theories.
One drop of ATF (Auto Trans Fluid) will produce MUCH smoke, so when the vacuam modulator diaphragm fails, the vacuam of the engine sucks that fluid into the RH inlet manifold.
Car starts to smoke, so owner shuts it down, and there it sits.
That fluid "soaks" into the alloy casting of that manifold.
Years later, one of us types rescues the car, and DRIVES it, alloy gets hot, the fluid is leached out, and mixes with more comong up from the transmission, coz that diaphragm is still broken.
End result, SMOKE.
Same scenario with brake fluid.
I would raise the car, safety PLEASE, coz the Jag will hurt you if it falls, and reach under the RH side, and between the exhaust pipe and the trans case you will see/feel, the modulator. It has a 90deg rubber elbow attached. Pull that elbow, CAREFULLY, and look for RED fluid in the modulator spigot, and/or the elbow. If there is the slightest sign of fluid, the modulator is dead.
It is a standard GM item, nothing special at all.
As for that AAV leaking coolant into the inlet system, NEVER, EVER seen one do that. OK, nothing is impossible, its a machine, but in all my dealings with the V12, NOPE.
Same for head gasket failure, rare in the big scheme of things. However, an overheated engine will cause those gaskets to fail at some time. Dropped valve seat is usually first.
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#11
#12
OB,
When they start, not much, except the smoke.
A real switched on driver, take that as you may anyone please, may detect slight changes in the upshift, but the smoke is now over riding all normal brain processing.
Once they let go, upshift is very delayed, but not many get to that, due to the smoke.
At the age of these things now, I would simply change them as you do any service item. They are cheap, PITA to get out, but well worth it in my opinion.
When they start, not much, except the smoke.
A real switched on driver, take that as you may anyone please, may detect slight changes in the upshift, but the smoke is now over riding all normal brain processing.
Once they let go, upshift is very delayed, but not many get to that, due to the smoke.
At the age of these things now, I would simply change them as you do any service item. They are cheap, PITA to get out, but well worth it in my opinion.
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#13
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#14
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#15
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orangeblossom (02-09-2017)
#16
Greg!
#17
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orangeblossom (02-09-2017)
#18
on the want one list.
After the new radiator, air conditioning repair and tackling the oil leak
Last edited by Paul_59; 02-09-2017 at 07:02 AM.
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orangeblossom (02-09-2017)
#19
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Interesting discussion. But, a minor point leaves me perplexed. If he engine is ingesting
ATF or brake fluid, why does it smoke out one pipe, not both?
Whereas a coolant leak on one bank would result in smoke on one pipe.
Perhaps inducing a smoke mode and holding a white paper into the smoke would catch some residue for simple or complex analysis.
Carl
Carl
ATF or brake fluid, why does it smoke out one pipe, not both?
Whereas a coolant leak on one bank would result in smoke on one pipe.
Perhaps inducing a smoke mode and holding a white paper into the smoke would catch some residue for simple or complex analysis.
Carl
Carl
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orangeblossom (02-09-2017)
#20