Dilemma Scout 07 - fix a worn inlet valve or sell the car for spares / repair?

[charlotteSimon]

Hi 

 

Just need some advice really.

 

My Scout started having misfire issues, intermittent, but getting worse.  I checked the data readout and it was showing a glow plug open circuit and after going through this forum decided it was a wiring issue, even though the injectors seem to be working fine.

 

Took it to my local trusted independent to sort out and they have come back and said it is most likely a damaged / worn inlet valve and will need to replace all valves.  

 

Clearly the cost goes way beyond what the car is worth, so the question is what to do.

 

Any thoughts?

[J.R.]

Get a proper diagnosis rather than a "most likely................."  "will cost you lots of money..........." = we dont know what it is & just want you to go away.

 

A compression test at the very minimum rather than sticking a finger in the air.

[MikeTheThinker]

2 hours ago, charlotteSimon said:

Hi 

 

Just need some advice really.

 

My Scout started having misfire issues, intermittent, but getting worse.  I checked the data readout and it was showing a glow plug open circuit and after going through this forum decided it was a wiring issue, even though the injectors seem to be working fine.

 

Took it to my local trusted independent to sort out and they have come back and said it is most likely a damaged / worn inlet valve and will need to replace all valves.  

 

Clearly the cost goes way beyond what the car is worth, so the question is what to do.

 

Any thoughts?

 

Apart from doing what @J.R. suggested give some thought to the condition of the car as it is otherwise.  Is it a clean runner or does it have other problems?  When was the cambelt last done?  Is the clutch OK?  Tyres, brakes etc.  all these add up when looking at the value of a car to keep versus sell.

 

I'm assuming yours is a 2.0tdi 6 speed BMM engine?

 

[charlotteSimon]

4 minutes ago, StickyMicky said:

 

Apart from doing what @J.R. suggested give some thought to the condition of the car as it is otherwise.  Is it a clean runner or does it have other problems?  When was the cambelt last done?  Is the clutch OK?  Tyres, brakes etc.  all these add up when looking at the value of a car to keep versus sell.

 

I'm assuming yours is a 2.0tdi 6 speed BMM engine?

 

HI - Yes I have taken that on board.  It is the model you suggest.  Tyres and brakes are recently changed....cambelt done at 116K.  Clutch I am not sure, seems OK.

 

They have quoted £1300 to complete the job.

[MikeTheThinker]

15 minutes ago, charlotteSimon said:

They have quoted £1300 to complete the job.

 

I'm not familiar with the garage labour rates in your area but that does seem a little steep for head off, reseat valves, replace seals and rebuild.  Are they suggesting skimming the head as well?

 

[charlotteSimon]

36 minutes ago, StickyMicky said:

 

I'm not familiar with the garage labour rates in your area but that does seem a little steep for head off, reseat valves, replace seals and rebuild.  Are they suggesting skimming the head as well?

 

To be honest i am not sure how long it would take though I am sure most of it is labour...

[Guest]

Can you tell us when the misfire occurs? cold/hot/RPM/type of driving you do etc.

 

I wouldn't worry about the glow plugs.

[J.R.]

Insist on a compression test because that £1300 spent on the "most likely" might be swiftly followed by the next expensive "most likely"

[charlotteSimon]

The misfire now happens all the time. Rough running at anything over idle, then losing power over about 2000.  My commute is about 10 miles each way and on one day about 30 miles each way.

[AudiPhile300]

Injector harness - you can replace it with a cheap for £25 or genuine for about £100 - 20 min job - mine went same symptoms - very common

 

I would consider overhauling the cylinder head, I had mine cleaned - new exhaust guides -  valves ground - crack tested - don't skim - scrape ! for £150

Take rocker cover off and look at camshaft lobes first - are they sharp on the peaks - indicates camshaft wear - new cam & followers (black nitrided) - £120- 200 cast or steel billet.

Head bolts £20  Cam bolts £20 Rocker shaft bolts - cap screws non-stretch - £15  and I would change the cam belt - tensioner at the same time - yes it mounts up, so just change the loom first :@)

 

Done a full rebuild on mine so any questions feel free to ask

 

atb

Mike

[AudiPhile300]

14 hours ago, MicMac said:

Can you tell us when the misfire occurs? cold/hot/RPM/type of driving you do etc.

 

I wouldn't worry about the glow plugs.

I would - failed glow plug will give over fuelling on that cylinder leading to excessive carbon build up and bore wash out, seized rings etc.  ALL Glowplugs should be functioning - they are cheap as chips so change them if they don't work !!

[J.R.]

Whilst I agree with the second part the first is rubbish, they only operate on cold starting and for a very short time post combustion, any unburnt fuel would only be during cranking.

 

PD's start in 1/4 turn in freezing conditions without any of the glowplugs working, VCDS said all mine were gone but I could not believe it, wiser folk than me on here disabused me and I changed them because they are cheap as chips but it has made no difference to starting.

 

To the OP Charlotte.

 

I am currently in West Sussex (near Gatwick) for 2 weeks and brought my VCDS with me if you want a free scan and a look over, PM me if that would help you decide what to do.

[charlotteSimon]

5 hours ago, AudiPhile300 said:

 

 

Done a full rebuild on mine so any questions feel free to ask

 

 

Ah OK!  Is yours a BMM as well?  I am very tempted to give it a go to be honest because apart from this issue it drives very nicely.  Saw another BMM at the mechanics this morning and mine is definitely in better condition than that one was....

 

It would be great if there was a list of items that need attention on these engines and then a list of the parts needed to sort them out!  Still Haynes is good and there are some great apps online for getting the parts through these days.

 

How long did it take you Mike?

1 hour ago, J.R. said:

I am currently in West Sussex (near Gatwick) for 2 weeks and brought my VCDS with me if you want a free scan and a look over, PM me if that would help you decide what to do.

 

That would be great.  I will PM you as I am very near to Gatwick.

[Guest]

5 hours ago, AudiPhile300 said:

I would - failed glow plug will give over fuelling on that cylinder leading to excessive carbon build up and bore wash out, seized rings etc.  ALL Glowplugs should be functioning - they are cheap as chips so change them if they don't work !!

 

Turbocharging and general engine condition aside,  a diesel engine isn't throttled like a petrol engine, it always has full air intake and RPM is controlled by the amount of diesel injected so it is for the most part always running in an oxygen rich condition.

 

If there was any over fuelling, it would result in higher engine RPM, not the situation you describe.

[J.R.]

He is probably imagining that the misfire described is one or more cylinders not combusting the mixture due to non working glowplugs, I was being polite when I used the word "rubbish", were it a petrol engine it would be a reasonable hypothesis but I think they dont understand the significance of the first word in "compression ignition".

 

The misfire will be caused by a lack of fuel (injector loom etc) or a lack of compression (valve/seat damage).

 

I love the simplicity of diesel engines in their basic operation, all the complexity is the rubbish bolted on around them for emissions etc.

[charlotteSimon]

On 15/07/2020 at 15:16, J.R. said:

 

The misfire will be caused by a lack of fuel (injector loom etc) or a lack of compression (valve/seat damage).

Hi.  Thanks for the advice to date.  Completed a test of compression and got 29 bar on all cylinders so i guess the issue is elsewhere - either injector loom or maybe turbo?

[Guest]

There goes your 'trusted' independent then!

 

Worthwhile getting another professional opinion.

 

Going by the age of the car it could very well be the injector wiring, a straight forward job with videos on the tube.

 

Another thing that came to mind since you write it's a progressive issue is worn camshaft lobes.

[charlotteSimon]

There is a bit of 'back draft' out the intake.  Could the lobes issue cause that or is that a red herring?

[Guest]

Possibly if the exhaust valve(s) closes prematurely due to worn lobe(s), a visual inspection should reveal more.

 

Has the engine had regular oil/filter changes with the correct grade of oil for a PD?

 

Has it become more noisy? If so describe.

 

What's the odometer reading/how is it driven?

 

When does the misfire occur? Cold/hot, low/high RPM,  under light/heavy load...

 

Of course it's difficult to diagnose via a forum, so many good technical responses get offered to posts only to have the OP reveal their own blunder previously.

 

I don't know that worn camshaft lobes are a contributing factor in your case or if a bad injector loom would show a DTC but if you were lifting the cam cover to check the wiring continuity you could assess both.

 

re wiring loom, it may be possible to repair if faulty, I've never heard of it being done only replaced but theoretically it should be possible.

 

* I've just reread your posts so some of the questions are answered already.

 

I'd suggest a more informed opinion before whipping the cam cover off for a peek but it's certainly looking likely your problem is there.

 

How do you know the injectors are working fine?

 

I would normally suggest an Italian tune up with a concentrated mix of fuel additive and BP Ultimate diesel but that may just be the nail in the coffin lid for it if there's mechanical wear issues.

[charlotteSimon]

16 hours ago, MicMac said:

Has the engine had regular oil/filter changes with the correct grade of oil for a PD?

Certainly there were a couple of years with nothing in the service book but was a company car at that point.

 

16 hours ago, MicMac said:

Has it become more noisy? If so describe.

Firstly I have noticed a more tappet type noise from it but have become used to this with diesels.  When accelerating the misfire noise becomes more apparent.

 

16 hours ago, MicMac said:

What's the odometer reading/how is it driven?

 

162,285 and I drive it about 30 miles per day when commuting with some long motorway drives about twice a month.

 

16 hours ago, MicMac said:

When does the misfire occur? Cold/hot, low/high RPM,  under light/heavy load..

From cold but more pronounced under load.

 

16 hours ago, MicMac said:

I'd suggest a more informed opinion before whipping the cam cover off for a peek but it's certainly looking likely your problem is there.

I will certainly try to get a more informed opinion on it and have one local to me who may well be able to help from a VAG perspective.  I will probably also do a visual because a) I have already bought a new gasket :-)) AND b) there is a small oil patch oozing from the seal near the tandem pump so I can fix that as well.

16 hours ago, MicMac said:

How do you know the injectors are working fine?

My AUTEL system shows them to be operating normally but to be honest who knows!

 

Oh well will need to get to look at the next bit and if it is camshaft at least I can change the belt and waterpump at the same time.....

[Guest]

It's sounding very like a worn camshaft.

 

I looked on the tube and injector wiring issues will show on a scan, the failure seems to be poor design where vibration causes the connectors to become loose.  The fix is simply nipping the female spade type fittings a little so that they grip the male pin tightly for an as new electrical contact.

 

Budget for a camshaft, lifters, bearing shells and new torque to yield bolts.

 

I think the problem (soft) camshafts were on 2003-2005'ish VAG models so maybe it's just naturally worn or the incorrect oil has been used.

[charlotteSimon]

So I have just got the injector rocker shaft off and found:

 

Cyl 1 rocker lobe deep gash in the metal 

 

Cyl 1 first lobe (inlet?) tip to toe 57.75mm

 

Cyl 2 first lobe 61.79mm 

 

Cyl 3 second lobe (exhaust?) 60.75

 

Cyl 4 second lobe very worn

 

Basically all but one of the lobes shows sign of wear but the lowest above was the worst by far. 

 

Have just ordered a new kit from Engine Team. 

 

Question though about how that deep gash could get there and the corresponding rocker is damaged? 

[Guest]

Poor metallurgy/manufacturing/incorrect oil.

 

Glad you sourced the problem and hopefully a rebuild gives you many more miles without further issue.

 

It may be worth magnet fishing in the old oil/filter to check for swarf that could potentially cause future wear, maybe something got past the filter.

 

Perhaps checking the oil pump pickup for debris.

Edited 2 August, 2020 by MicMac

[J.R.]

Kudos to you MicMac, you were dead right in your diagnosis.

[charlotteSimon]

7 hours ago, MicMac said:

Perhaps checking the oil pump pickup for debris.

Yep poking around the oil in the area around the injectors produced a bearded magnetic screwdriver!! 
 

thanks for your input into this. 
 

I cannot help feeling that someone replaced the rocker shafts and skipped the cam at some point in the past...

 

cheers

 

simon