Heavily Oil Fouled Plugs, VW Polo
Discussion
just completed a top end Engine Rebuild & more on beloved's 2005 1.2 Polo (BMD 3 Pot lump), it had done its Exhaust Valves and Head Gasket.
It was fabulous: first start was immediate (good job coz the Battery was well past it - now replaced), ran nice, loadsa power (certainly more than you'd expect for the engine)
A week, 150miles and a full 45mins ticking over on the drive running it up to temp and checking the rad was hot top to bottom (and the Heater blowing hot) to make absolutely sure it was bled OK - not to mention stoppping countless times to do similar on its first 30mile run out, which was also just fine & dandy....
...now its all gone rather badly wrong
I found myself struggling to even so much as pull away in town at the weekend (a 10mile journey in itself), with no tools in the car. (unsurprising given the state of these and the woeful spark I got when I turned it over with the plugs on the rocker cover)
It can't be getting past the Piston Rings, coz it runs & sounds sweet, there's certainly no Piston Slap and there's plenty of power
If it was Head Gasket (the Head was skimmed of course), surely it'd be unlikely to be fouling all three plugs...???
Which makes me think, could I have made an error in fitting the new Valve Stem Seals? Not pressed them down sufficiently or something? Would there be a way to prove this?
Any other thoughts?
Could it be a cracked Head / Block and will I be able to see this with the naked eye / or feel it?
Thanks in advance
PS: obviously the Head's coming off again, so it'll get a second Head Gasket, but should I change the (new of course) Head Bolts too? Tightening and Torque-ing / Angle Tightening procedures were followed.
PPS: that was the ONLY blue smoke, on cold start. The exhaust was clean all the way home, I uploaded the Dash Cam from my car, which beloved was following me in
Further files can be made available: pix, video, etc
It was fabulous: first start was immediate (good job coz the Battery was well past it - now replaced), ran nice, loadsa power (certainly more than you'd expect for the engine)
A week, 150miles and a full 45mins ticking over on the drive running it up to temp and checking the rad was hot top to bottom (and the Heater blowing hot) to make absolutely sure it was bled OK - not to mention stoppping countless times to do similar on its first 30mile run out, which was also just fine & dandy....
...now its all gone rather badly wrong
I found myself struggling to even so much as pull away in town at the weekend (a 10mile journey in itself), with no tools in the car. (unsurprising given the state of these and the woeful spark I got when I turned it over with the plugs on the rocker cover)
It can't be getting past the Piston Rings, coz it runs & sounds sweet, there's certainly no Piston Slap and there's plenty of power
If it was Head Gasket (the Head was skimmed of course), surely it'd be unlikely to be fouling all three plugs...???
Which makes me think, could I have made an error in fitting the new Valve Stem Seals? Not pressed them down sufficiently or something? Would there be a way to prove this?
Any other thoughts?
Could it be a cracked Head / Block and will I be able to see this with the naked eye / or feel it?
Thanks in advance
PS: obviously the Head's coming off again, so it'll get a second Head Gasket, but should I change the (new of course) Head Bolts too? Tightening and Torque-ing / Angle Tightening procedures were followed.
PPS: that was the ONLY blue smoke, on cold start. The exhaust was clean all the way home, I uploaded the Dash Cam from my car, which beloved was following me in
Further files can be made available: pix, video, etc
Edited by VanDiesel99 on Wednesday 14th December 19:18
ked.Thanks everyone.
To attempt to reply: am pretty sure this engine doesn't have a PCV system. Can't say whether its using oil coz of only having done 150miles since the top end rebuild.
Foobarred valves: it's common on these 9N engines fitted to Polo, Fabia, Fox and others. All the Exhausts were decidely unpretty (photo). Not sure of the science of them getting this bad
Valve guides... now that's a good call I'd say. Have spent today researching how to check and how to replace them.
Still really nasty weather here today, temps haven't been above freezing for about 5 days (and I've no Garage) so no spannering today.
To attempt to reply: am pretty sure this engine doesn't have a PCV system. Can't say whether its using oil coz of only having done 150miles since the top end rebuild.
Foobarred valves: it's common on these 9N engines fitted to Polo, Fabia, Fox and others. All the Exhausts were decidely unpretty (photo). Not sure of the science of them getting this bad
Valve guides... now that's a good call I'd say. Have spent today researching how to check and how to replace them.
Still really nasty weather here today, temps haven't been above freezing for about 5 days (and I've no Garage) so no spannering today.
VanDiesel99 said:
Thanks everyone.
To attempt to reply: am pretty sure this engine doesn't have a PCV system.
I think it does To attempt to reply: am pretty sure this engine doesn't have a PCV system.
https://volkswagen.7zap.com/en/rdw/polo+derby+vent...
item 30
Also burnt out valves and worn guides seem to be common
https://www.volkswagenforum.co.uk/threads/1-2-3-cy...
It also suggests piston rings wear but the pain of this engines is, the crank case is in two halves that are not meant to be separated and its easy to distort the block when torqueing up and essentially means its a throw away engine as I think you need to separate the block to get at the big ends.
I had the 12 valve version and it was a cracking little engine, ran for 100k and still pulled better than our current 1.0 polo but the simplex timing chain stretches and I had to replace it and all the guides, tensioner, sprockets. Not sure about your engine, but it might be worth thinking about doing while its in bits. Don't think it would suffer the sprocket jump the 12v suffers from but I bet it still stretches.
https://www.volkswagenforum.co.uk/threads/1-2-3-cy...
It also suggests piston rings wear but the pain of this engines is, the crank case is in two halves that are not meant to be separated and its easy to distort the block when torqueing up and essentially means its a throw away engine as I think you need to separate the block to get at the big ends.
I had the 12 valve version and it was a cracking little engine, ran for 100k and still pulled better than our current 1.0 polo but the simplex timing chain stretches and I had to replace it and all the guides, tensioner, sprockets. Not sure about your engine, but it might be worth thinking about doing while its in bits. Don't think it would suffer the sprocket jump the 12v suffers from but I bet it still stretches.
Edited by Gary C on Friday 16th December 07:52
Thanks, I’d been expecting to see something that was attached to the Crankcase rather than near the top of the Timing Chain Cover. Still a bit doubtful about that for the reasons mentioned in my initial post, including checking for venting from the Dipstick tube, but will be checking the Manifold upon removal.
I certainly could’ve missed Valve Guide wear when this is only my second head rebuild; due to inexperience. The previous one was my XUD, an engine that was properly engineered in the first place and therefore had proper mileage on it before needing a rebuild
To my recollection all the Valves were a tight fit, so much so that I put a smear of oil on each to ease fitting and provide lubrication on initial start up
Block distortion is something I’m gonna have to be cautious of and that I need to learn more about, ‘specially as I’ve still found no issue with its original HG, which hasn’t been cleaned, I’ve deliberately not so much as wiped a rag across it.
Oil was pouring from the rear of Pot 1 (Timing end) and seeping down the Timing Chain cover / spraying onto the Aux Belt / nestling in the recess atop the Water Pump and being thrown forward to make a huge mess. I’ve looked particularly carefully at the HG there and can see no evidence of an issue. As you can see in one of the pics, Pots 2 & 3 were full of coolant too, with plenty of coolant also found on blowing out the Head Bolt holes around Pot 3.
That’s no longer the case, oil’s now seeping (I think) from the front of the same pot, behind the Alternator… I’ll need to be having the Alternator, AC Compressor and Exhaust Manifold / Cat off before I can see properly. I'm not confident that there's not a bit of steam coming out the exhaust on tickover too (albeit not when driven, have ordered some solution to test it - have only got the Diesel test solution)
I’ve a pane of Glass and an Aluminium yardstick to check for straight. Any other suggestions for ensuring its straight? I’m confident it’s never been boiled.
And should the separate layers of the HG have been apparent? You could feel the play between them with the new HG prior to fitting; I never felt this previous, but then, I’ve only done one.
I’ve done the Timing Chain & Oil Chain as part of the rebuild; in fairness you only expect 100k or thereabouts from a Timing Chain and it was close. It had startled to rattle on cold start and there were witness marks on the top of the Timing Cover. I was shocked when watching a You Tuber who repairs VAG salvage stuff and he suggested that there was a strong possibility of a timing chain being worn out at mere 65k miles… if abused or neglected, yes; but otherwise, that’s ridiculous!
Missus’ little 6 BMD Valve really goes well for what it is, would probably give my Focus TDCi a run for its money thru the gears, driven hard (specially as that’s not breathing partic well thru a carboned up early type (so a pig to remove) Inlet Manifold and with a noisy DMF too; so it's not 100% itself and its that I'd anticipated being off the road now, not the VW)...
...but what really lets the Polo down is the ride. OK, I’ve come from 14 years of running a Pug 405, so its got a lot to live up to; but it is poor. Is the 12v the AZQ? (I know it’s the same bottom end). The Book of Lies specifically says that the bottom end of this engine is not rebuild-able, without stating why; so that could be it regarding the Big Ends.
I’d be more inclined to scrap it if it wasn’t yellow, but that it was yellow was her one criteria for her ‘new car’ 3 years ago and rust-wise, its really good; plus its very economical and at this end of the market, finding a replacement that’s not just a heap of someone else’s trouble is difficult. We were 'there' with daughter's car last year, her C-Max seized up and was weighed in New Year's Day. Took me a month and many hundreds of miles travelled to find her a replacement car. Some of the stories i got.... (gasp)!!! including my favourite "its sold as scrap sir [from my traders' forecourt]...". My reply, "so why's it not scrap money then?!"
Thanks for your help
Photos....
I certainly could’ve missed Valve Guide wear when this is only my second head rebuild; due to inexperience. The previous one was my XUD, an engine that was properly engineered in the first place and therefore had proper mileage on it before needing a rebuild
To my recollection all the Valves were a tight fit, so much so that I put a smear of oil on each to ease fitting and provide lubrication on initial start up
Block distortion is something I’m gonna have to be cautious of and that I need to learn more about, ‘specially as I’ve still found no issue with its original HG, which hasn’t been cleaned, I’ve deliberately not so much as wiped a rag across it.
Oil was pouring from the rear of Pot 1 (Timing end) and seeping down the Timing Chain cover / spraying onto the Aux Belt / nestling in the recess atop the Water Pump and being thrown forward to make a huge mess. I’ve looked particularly carefully at the HG there and can see no evidence of an issue. As you can see in one of the pics, Pots 2 & 3 were full of coolant too, with plenty of coolant also found on blowing out the Head Bolt holes around Pot 3.
That’s no longer the case, oil’s now seeping (I think) from the front of the same pot, behind the Alternator… I’ll need to be having the Alternator, AC Compressor and Exhaust Manifold / Cat off before I can see properly. I'm not confident that there's not a bit of steam coming out the exhaust on tickover too (albeit not when driven, have ordered some solution to test it - have only got the Diesel test solution)
I’ve a pane of Glass and an Aluminium yardstick to check for straight. Any other suggestions for ensuring its straight? I’m confident it’s never been boiled.
And should the separate layers of the HG have been apparent? You could feel the play between them with the new HG prior to fitting; I never felt this previous, but then, I’ve only done one.
I’ve done the Timing Chain & Oil Chain as part of the rebuild; in fairness you only expect 100k or thereabouts from a Timing Chain and it was close. It had startled to rattle on cold start and there were witness marks on the top of the Timing Cover. I was shocked when watching a You Tuber who repairs VAG salvage stuff and he suggested that there was a strong possibility of a timing chain being worn out at mere 65k miles… if abused or neglected, yes; but otherwise, that’s ridiculous!
Missus’ little 6 BMD Valve really goes well for what it is, would probably give my Focus TDCi a run for its money thru the gears, driven hard (specially as that’s not breathing partic well thru a carboned up early type (so a pig to remove) Inlet Manifold and with a noisy DMF too; so it's not 100% itself and its that I'd anticipated being off the road now, not the VW)...
...but what really lets the Polo down is the ride. OK, I’ve come from 14 years of running a Pug 405, so its got a lot to live up to; but it is poor. Is the 12v the AZQ? (I know it’s the same bottom end). The Book of Lies specifically says that the bottom end of this engine is not rebuild-able, without stating why; so that could be it regarding the Big Ends.
I’d be more inclined to scrap it if it wasn’t yellow, but that it was yellow was her one criteria for her ‘new car’ 3 years ago and rust-wise, its really good; plus its very economical and at this end of the market, finding a replacement that’s not just a heap of someone else’s trouble is difficult. We were 'there' with daughter's car last year, her C-Max seized up and was weighed in New Year's Day. Took me a month and many hundreds of miles travelled to find her a replacement car. Some of the stories i got.... (gasp)!!! including my favourite "its sold as scrap sir [from my traders' forecourt]...". My reply, "so why's it not scrap money then?!"
Thanks for your help
Photos....
Shedding said:
Is it definite that on this engine you can't get to the big-end bearings to remove a piston without splitting the block?
Not sureI've not done it but the link suggested it might be necessary and its worth a warning that undoing the crankcase bolts can scrap the engine and there aren't even any published torque figures for doing them back up !
Edited by Gary C on Friday 16th December 18:27
still in the quest to seek where I went wrong....
Angle Tightening: must it be done as 'one pull'.
On at least a couple of the Cylinder Head Bolts, I did the 90degree angle tighten in two separate 'pulls' (eg 60 + 30, or 45 + 45)
I was, however, careful to be accurate, using a proper Angle Tightening Gauge
Could this be part / all of the reason for my woes?
Specs on this are (from memory) 30Nm + 90 Degrees angle tighten, twice
Angle Tightening: must it be done as 'one pull'.
On at least a couple of the Cylinder Head Bolts, I did the 90degree angle tighten in two separate 'pulls' (eg 60 + 30, or 45 + 45)
I was, however, careful to be accurate, using a proper Angle Tightening Gauge
Could this be part / all of the reason for my woes?
Specs on this are (from memory) 30Nm + 90 Degrees angle tighten, twice
VanDiesel99 said:
The Book of Lies specifically says that the bottom end of this engine is not rebuild-able, without stating why; so that could be it regarding the Big Ends.
Its the main bearings. The crank case is in two halves and the crank sits in between these halves so to get at them you have to separate them. Problem is, they are quite light aluminium castings and they don't have the strength to carry an unequal load from the bolts so if they are not untightened and retightened very very carefully, the block with distort.The head should not have distorted the block though. I imagine you de-torqued the head in an equal fashion as well as tightening it ?
But, you had a problem before you rebuilt with burning oil ?
There does seem to be a lot of oil in the bores, So its either passing the guides, the rings or the head gasket ?
VanDiesel99 said:
still in the quest to seek where I went wrong....
Angle Tightening: must it be done as 'one pull'.
On at least a couple of the Cylinder Head Bolts, I did the 90degree angle tighten in two separate 'pulls' (eg 60 + 30, or 45 + 45)
I was, however, careful to be accurate, using a proper Angle Tightening Gauge
Could this be part / all of the reason for my woes?
Specs on this are (from memory) 30Nm + 90 Degrees angle tighten, twice
No, 2x45° will be just the same result.Angle Tightening: must it be done as 'one pull'.
On at least a couple of the Cylinder Head Bolts, I did the 90degree angle tighten in two separate 'pulls' (eg 60 + 30, or 45 + 45)
I was, however, careful to be accurate, using a proper Angle Tightening Gauge
Could this be part / all of the reason for my woes?
Specs on this are (from memory) 30Nm + 90 Degrees angle tighten, twice
Thanks Guys.
Not taken a spanner to it yet, but:-
the weather's warmed up
the parts have arrived (and some new tools)
the straight edge I'm going to use to check the Head & Block has been checked to indeed be straight
and I've got notes of various things to do in what order, eg
taking it for a drive with the Missus following (with Dashcam)
Doing a compression test (albeit things being awry there are a bit of a 'given')
Removing the PCV Valve, Inlet manifold etc.
Will be ensuring I get relevant pix in the course of investigating and will give you all an update....
When I start it will depend on whether or not I book myself and my Beloved a cheap holiday.... its not every day you find yourself doing a major job twice; so a bit of sunshine might help to lift my spirits. Least the access is nice n easy!
Not taken a spanner to it yet, but:-
the weather's warmed up
the parts have arrived (and some new tools)
the straight edge I'm going to use to check the Head & Block has been checked to indeed be straight
and I've got notes of various things to do in what order, eg
taking it for a drive with the Missus following (with Dashcam)
Doing a compression test (albeit things being awry there are a bit of a 'given')
Removing the PCV Valve, Inlet manifold etc.
Will be ensuring I get relevant pix in the course of investigating and will give you all an update....
When I start it will depend on whether or not I book myself and my Beloved a cheap holiday.... its not every day you find yourself doing a major job twice; so a bit of sunshine might help to lift my spirits. Least the access is nice n easy!
Thanks Gary... I might be needing that luck !!
Compression Figures are in, they're surprisingly good, would welcome your (everyone's) thoughts.
I note that compression does "gradually rise on successive strokes", which Haynes says suggests bad piston rings....
Photos and Videos are at
(AFAIK you can't upload vids to PH)
https://www.dropbox.com/sh/kz7tz8ik2066o1o/AADigYG...
Note that three of these are videos, just press play
I've not had the PCV Valve off yet, or the Alternator to confirm that there's oil coming out of the forward face of the head on Pot 1. The weather wasn't kind, it was going from nice n sunny to short heavy showers; which is far from ideal when you're working outside... but what can you expect in December eh!
Borrowed Gauge, its this one in the photos and videos I've uploaded
Pot 1: 12 Bar
Pot 2: 13 ¾ Bar
Pot 3: 14 Bar
My Gauge (Bar) – second figure with +3ml Oil added
Pot 1: 11 Bar / 11.5 Bar
Pot 2: oops / 13.5 Bar
Pot 3: 13 Bar / 13.5 Bar
Oops = Compression figure not known, user error; I probably overlooked to hit ‘Start’ on the video
(According to Haynes, I should have 11 Bar Max !!)
My Gauge (psi) – second figure with +3ml Oil added
Pot 1: 155psi / 165psi
Pot 2: oops / 190psi
Pot 3: 185psi / 195psi
Oops = Compression figure not known, user error; I probably overlooked to hit ‘Start’ on the video
PLUGS...
Pot 1: Plug oil fouled (Brown Taped), worst plug, suspected oil leak from Head not yet confirmed and obvious oil leaks evident beneath aux belt on undertray
Pot 2: No Oil Fouling, plug colour is good (Black Taped)
Pot 3: Plug oil fouled, not as badly as Pot 1 (not taped)
Plugs were thoroughly cleaned prior to this 5 mile road test, under various conditions including
Long period of idling & set off normally
Deliberate <1200rpm labouring uphill
5000rpm thrash thru the gears, uphill
Coming harshly down the gears to about 3500rpm on each down change
Exhaust was clean under all circumstances
Header Tank: no evidence of oil contamination
There's obvious evidence of oil in the recess between three of the Cylinder Head Bolts and the Rocker Cover, in addition to quite a lot of oil ahead of the Oil Filler, which I’m near certain I haven’t spilt; as circled and I know it was clean when I rebuilt it. Could that be coming up the Head Bolts? There's no evidence of rocker cover leaks
Scuse fact that my phone recorded a mirror image, that’s why there’s a mirror image of the Compression tester included in the photos here
Should my Dropbox get hacked, its not the end of the world, there’s nothing there of great importance that I haven't got safely stored offline
Compression Figures are in, they're surprisingly good, would welcome your (everyone's) thoughts.
I note that compression does "gradually rise on successive strokes", which Haynes says suggests bad piston rings....
Photos and Videos are at
(AFAIK you can't upload vids to PH)
https://www.dropbox.com/sh/kz7tz8ik2066o1o/AADigYG...
Note that three of these are videos, just press play
I've not had the PCV Valve off yet, or the Alternator to confirm that there's oil coming out of the forward face of the head on Pot 1. The weather wasn't kind, it was going from nice n sunny to short heavy showers; which is far from ideal when you're working outside... but what can you expect in December eh!
Borrowed Gauge, its this one in the photos and videos I've uploaded
Pot 1: 12 Bar
Pot 2: 13 ¾ Bar
Pot 3: 14 Bar
My Gauge (Bar) – second figure with +3ml Oil added
Pot 1: 11 Bar / 11.5 Bar
Pot 2: oops / 13.5 Bar
Pot 3: 13 Bar / 13.5 Bar
Oops = Compression figure not known, user error; I probably overlooked to hit ‘Start’ on the video
(According to Haynes, I should have 11 Bar Max !!)
My Gauge (psi) – second figure with +3ml Oil added
Pot 1: 155psi / 165psi
Pot 2: oops / 190psi
Pot 3: 185psi / 195psi
Oops = Compression figure not known, user error; I probably overlooked to hit ‘Start’ on the video
PLUGS...
Pot 1: Plug oil fouled (Brown Taped), worst plug, suspected oil leak from Head not yet confirmed and obvious oil leaks evident beneath aux belt on undertray
Pot 2: No Oil Fouling, plug colour is good (Black Taped)
Pot 3: Plug oil fouled, not as badly as Pot 1 (not taped)
Plugs were thoroughly cleaned prior to this 5 mile road test, under various conditions including
Long period of idling & set off normally
Deliberate <1200rpm labouring uphill
5000rpm thrash thru the gears, uphill
Coming harshly down the gears to about 3500rpm on each down change
Exhaust was clean under all circumstances
Header Tank: no evidence of oil contamination
There's obvious evidence of oil in the recess between three of the Cylinder Head Bolts and the Rocker Cover, in addition to quite a lot of oil ahead of the Oil Filler, which I’m near certain I haven’t spilt; as circled and I know it was clean when I rebuilt it. Could that be coming up the Head Bolts? There's no evidence of rocker cover leaks
Scuse fact that my phone recorded a mirror image, that’s why there’s a mirror image of the Compression tester included in the photos here
Should my Dropbox get hacked, its not the end of the world, there’s nothing there of great importance that I haven't got safely stored offline
Edited by VanDiesel99 on Thursday 29th December 15:37
Edited by VanDiesel99 on Thursday 29th December 15:44
Gassing Station | Home Mechanics | Top of Page | What's New | My Stuff