4.2 SC LOTS of white smoke...

Henry_b · Mar 20, 2019

Grrrrrr said:
It does but I didn't dare risk it on my Jag.

The Jag engine is sublime. Bit of an issue with tensioners on earlier models but we'll before yours. Seem to remember some pipe in the v giving issues but maybe I am mixing that up with something else.

That'll be the valley pipe..

And it does go pop..

Bastard thing, only thing i can think of that plagues the 4.2 and 4.4 AJ the 4.0 and 3.2 did have tensioner and nikasil issues but thats long gone..

Pipe is a 6hr job on the S/c and a 2hr job on the N/A.

But OP would get a drastic drop in coolant.

ukadamwest · Mar 20, 2019

Henry_b said:
That'll be the valley pipe..

And it does go pop..

Bastard thing, only thing i can think of that plagues the 4.2 and 4.4 AJ the 4.0 and 3.2 did have tensioner and nikasil issues but thats long gone..

Pipe is a 6hr job on the S/c and a 2hr job on the N/A.

But OP would get a drastic drop in coolant.

as a thought, would a drop in coolant only show when the tstat has opened and allowing the coolant to circulate ?

Henry_b · Mar 20, 2019

ukadamwest said:
as a thought, would a drop in coolant only show when the tstat has opened and allowing the coolant to circulate ?

The pipe is after the Stat so yes..

when it goes pop you know about it.

A cheap rubber pipe in an unfavourable place isn't an ideal combo..

It'll lose all the coolant in under a minute..

ukadamwest · Mar 20, 2019

Henry_b said:
The pipe is after the Stat so yes..

when it goes pop you know about it.

A cheap rubber pipe in an unfavourable place isn't an ideal combo..

It'll lose all the coolant in under a minute..

well that's worth knowing. I look forward to it happening !

Henry_b · Mar 20, 2019

ukadamwest said:
well that's worth knowing. I look forward to it happening !

Whats her mileage?

ukadamwest · Mar 20, 2019

Henry_b said:
Whats her mileage?

enough that it will go

Mark Piercy · Mar 20, 2019

I would pull the plugs out one by one and see if you have fuel jetting from a cylinder. I found on an Audi A4 2.0tfsi an Injector had jammed open causing thick white smoke and stank really badly of petrol. I removed the it's and found a jet of petrol coming from the offending cylinder. While you've got them out check for any anitfreeze burnt onto any plugs and do a compression test as well to rule out a blown gasket... Good luck.. it as said and quite rightly, If it's under any warranty...for it back and run to the hills..

Henry_b · Mar 20, 2019

ukadamwest said:
enough that it will go

Over 100k is usually the "zone"

Rawlplug · Mar 20, 2019

ukadamwest said:
ok. you're talking the engine top cover that has two 10mm bolts that sit under the scuttle panel and you have to take the oil filler off to get the cover out ?
why did you take the cover off ? just having a look at belts ect or a specific reason (note, I just got a 4.2SC too and working through things not happy with - see my thread on 4.2 SC niggles and needs)

under that cover, as you know sits the intake for forced induction. and the big arsed clips that hold it in place are after the MAF. if they are not tight, then the intake will suck in unmetered air and a lean burn will occur as the engine is reading the air going in through the filter and not metering the air being sucked in after the MAF. and you'll get a lean burn.

white smoke is often the case when the crankcase pressure is too high, forcing oil through to the combustion chamber. with the oil cap off, your crankcase pressure would be reduced.. but a stuck CCV would result in PO171 / P0174 and white smoke. it fits ! maybe the CCV was weak and running it with the oil cap off has hastened its failure... try the oil cap test per the video

Correct, two bolts, but also the two to take the cabin air filer out to access the bolt at the back. I only took it off to have a nose round to see if there was an obvious air leak.
The CCV idea would seem to be a possible cause for all the symptoms - but on petrol only and not LPG?

I want to start her again just to check the smell of the smoke and to double check all goes away when the LPG runs. Do you think it's safe to do that? Am i risking damaging the engine?

Rawlplug · Mar 20, 2019

Mark Piercy said:
I would pull the plugs out one by one and see if you have fuel jetting from a cylinder. I found on an Audi A4 2.0tfsi an Injector had jammed open causing thick white smoke and stank really badly of petrol. I removed the it's and found a jet of petrol coming from the offending cylinder. While you've got them out check for any anitfreeze burnt onto any plugs and do a compression test as well to rule out a blown gasket... Good luck.. it as said and quite rightly, If it's under any warranty...for it back and run to the hills..

No warranty! I think pulling the plugs and looking for fuel jetting might be beyond my technical prowess - what would I be looking for exactly? If I assume it's a stuck injector, would the engine be safe to run with some injector cleaner just to see if it clears? Got some Forte stuff arriving tomorrow. Would a stuck injector wash the bore and result in scoring?

ukadamwest · Mar 20, 2019

that's what is confusing me that its not doing it on LPG. I cant see it being overfueling, as fuel wouldn't give white smoke. you'll need to start it to check the crankcase pressure.

Mark Piercy · Mar 20, 2019

Rawlplug said:
No warranty! I think pulling the plugs and looking for fuel jetting might be beyond my technical prowess - what would I be looking for exactly? If I assume it's a stuck injector, would the engine be safe to run with some injector cleaner just to see if it clears? Got some Forte stuff arriving tomorrow. Would a stuck injector wash the bore and result in scoring?

Washing out a bore is a risk.
You could do with some help then. If an injector is stuck open. I.e firing a constant jet of fuel into the barrel it will be ejected from the cylinder when the piston returns to the top of its vinegar stroke. I hope this is not the case for you but get some help.

Henry_b · Mar 20, 2019

Surely that will cause a misfire condition..

What does it rev like?

Any hesitation?

jamesmartin · Mar 20, 2019

ukadamwest said:
that's what is confusing me that its not doing it on LPG. I cant see it being overfueling, as fuel wouldn't give white smoke. you'll need to start it to check the crankcase pressure.

why not white smokes water or unburnt fuel

Mark Piercy · Mar 20, 2019

ukadamwest said:
that's what is confusing me that its not doing it on LPG. I cant see it being overfueling, as fuel wouldn't give white smoke. you'll need to start it to check the crankcase pressure.

The last car I dealt with having an jammed injector smoked like a train... Thick white smoke...now my ignorance comes into it here, when the lpg kicks in the injectors are cut out of play?

Henry_b · Mar 20, 2019

Mark Piercy said:
The last car I dealt with having an jammed injector smoked like a train... Thick white smoke...now my ignorance comes into it here, when the lpg kicks in the injectors are cut out of play?

Yes they "turn off"

jamesmartin · Mar 20, 2019

Mark Piercy said:
Washing out a bore is a risk.
You could do with some help then. If an injector is stuck open. I.e firing a constant jet of fuel into the barrel it will be ejected from the cylinder when the piston returns to the top of its vinegar stroke. I hope this is not the case for you but get some help.

ive seen rover v8s burn pistons through from stuck open injectors

Mark Piercy · Mar 20, 2019

Henry_b said:
Surely that will cause a misfire condition..

What does it rev like?

Any hesitation?

That's true if you know how to spot a missfire.. depending on how open the injector is..

Mark Piercy · Mar 20, 2019

Do these buggers have a water cooled egr valve unit?
Any coolant loss at all? @Rawlplug

Henry_b · Mar 20, 2019

Mark Piercy said:
Do these buggers have a water cooled egr valve unit?

No.

4.2 SC LOTS of white smoke...

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