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Dirty Spark Plug = Major Problem?

JulesInFrance

JulesInFrance

New member
Houston, I think I have a problem.

My 2005 997.1 developed a misfire in cylinder 6 a while back, after which I have not used the car. I finally got around to investigating today and found a very dirty spark plug. In fact it was more than dirty, it was gungey. I have a suspicion what might be causing it but it's a long story and I thought I would post a simple question here first, before going into details, to see if any immediate reactions corroborate the theory.

I have attached a photo of plugs 5 (right) and 6 (left), you may have to zoom in a bit, both of which in fact look a bit dodge, but 6 is a real concern I think.

Any thoughts? Am I in trouble?

Many thanks in advance,
Jules
 
How many miles? Manual or Tip? Cylinder no’s quoted sounds like gen 1 hell...
 
If you were really lucky it could be a duff plug, but the fact its oily is worrying, the other one doesn't look good either, while they are out why dont you buy one of those cheap endoscopes on ebay and have a look see inside.
 
Hmm. This might not be worst-case-scenario bore scoring. I'd suspect the Air-Oil Separator first.
 
Good morning and thanks to all who have replied to my call for help!

Sorry about the delay in responding. I in fact have had an endoscope for a few years (highly recommend them, very useful for many things and thanks for the Timbo2 for the suggestion). However it needed a memory card in order to take photos so I was waiting for that to arrive. Said card is now here so photos are below.

In response to jcat, the car has done about 80,000 miles and is tiptronic. I previously read (before buying the car) that if cylinder scoring had not occurred before 50,000 miles, it was very unlikely to occur. However, reading more on the matter yesterday, I have found articles which say this is not true and that it is probably bound to happen sooner or later anyway. I should have done more research.

The air/oil seperator is an interesting theory (tanks STiG911) and I guess I can check it. I suppose the theory here is that it is sucking oil up from the crank case and throwing it back into the air intake? If this is so, is there an easy check I could make, as presumably somewhere along the line, the air intake would be oily? However, as neilmasrshall said, would that only affect one cylinder (or two)? Surely they would all be the same? I suppose if I were to look at the plugs and pots the other side of the engine, this may reveal more.

Anyway, here are some photos (I'm not sure if the photo links have worked so have put manual links in too). All three show soot on top of piston 6. The first two show what I think looks like definite scoring
s!AiTXc_fI742A2lN816REQjgzWO2a
(https://1drv.ms/u/s!AiTXc_fI742A2lN816REQjgzWO2a) and
s!AiTXc_fI742A2lXFnoG9Z5kz57ia
(https://1drv.ms/u/s!AiTXc_fI742A2lXFnoG9Z5kz57ia). The last picture shows oil sitting at the bottom of the cylinder:
s!AiTXc_fI742A2lTms40DggzNsyij
(https://1drv.ms/u/s!AiTXc_fI742A2lTms40DggzNsyij).

I think these photos are pretty convincing and I am preparing myself for the worst. I will try to get an opinion from Hartech but in the meantime would be very grateful for any further insights from you guys.

Many thanks,
Jules
 
The thrust side of the bores will always show some lines, however picture two, high left, does appear to have deeper grooves. You are correct in getting an expert opinion.
The easiest way to check the AOS is to removed intake tube from the throttle body. There will be obvious oil contamination on MAF etc. if the AOS is passing oil.
 
Sorry to hear about your problem Jules. Unfortunately it would appear that bore scoring is the most likely cause, especially since cylinder number 6 is involved.

Didn't we have a conversation some time ago when you mentioned that the (French?) Porsche dealer had seriously underfilled the engine with oil at a service? If so that can't have helped, and it may be worth having a conversation with them once you've got an assessment from Hartech.

Jeff
 
Thanks Geoff997, I will do that check just to eliminate the AOS as being the problem.

997Mike, it's a 3.8. Were they more susceptible to cylinder scoring than the 3.6?

And Jeff, yes! You have a good memory! The problem with going back to Porsche Toulouse at the time was that they denied the mistake saying that the oil refill is measured by machine and therefore impossible to get wrong in their eyes. I did not pursue it hard as there is no way I can prove their error and I felt that if I tried, they would just find ways of charging me more money. They are 2 1/2 hours from me and won't pay at all for any incidental costs of getting the car back to them. Now the car is undrivable, that situation is compounded. I do have an email chain showing my inquiries with them and their responses (or lack of most of the time) so now I will pursue it again, and will also involve Porsche France and Porsche Germany if necessary. It is a fact, albeit unprovable, that the car used no oil before that service and used 1/2 litre every 500 km afterwards, so yes, I think that is where the damage was done. The whole thing stinks to be honest. The only slightly positive I have got from this so far is that Hartech basic quotes for the rebuilds they do are nowhere near the £10K I have seen posted elsewhere on the internet for correction of cylinder scoring. I will write to them over the weekend and see what they say. I don't trust Porsche France at all now and would worry about anyone else in France doing the work, unless there is a Hartech equivalent, but even if there is, I suspect they would charge far more. Obviously to add to the problem, apart from the cost, is the issue of how to get the car to Hartech! I don't have a car trailer and getting someone else to take it on a flatbed would just cost more. Aaaarrrgggh!!!!!

I will post more once I get a response from Hartech.

Jules
 
Hi Jules,
Regarding AOS, if you cannot open the flexi hose that sits and clips to top of airbox due to suction while engine is on then it is the AOS.

The Porsche Specialist I use immediately got to this route cause. The symptoms I had was a squealing noise, also similar to the noise on a metal pulley being pulled and abnormal white smoke on cold start up.

With regards to whether its bore scoring, the left exhaust, passenger side would have more oil burn deposit than the right. This is at least what my Porsche Specialist has told me as a sign off bore scoring.

Hope this helps. Good luck.
 
Check the exhaust tips for signs of soot.
I think if it were me, I would have cylinder leakage and compression tests undertaken by a competent indy, just to confirm condition before instigating any expensive engine repairs.
Regards,

Clive
 
Jules,

Given your location and predicament I'd be inclined initially to do as Clive suggests and get cylinder leakage and compression tests undertaken locally. Any reasonably competent garage will be able to do this for you and it should determine if the problem lies more likely with bore wear or with valve guide leakage, the latter being more easily rectified and at much lower cost than a full engine rebuild.

If indeed you do choose to get the engine rebuilt by Hartech then I suspect that it would be much cheaper to have it removed locally and transported to them as a unit.

Have you considered contacting Porsche Club France for advice about local Porsche Independents who could help?

Jeff
 
If you were going to spend money on garage assessment I would advise a borescope over a cylinder leakage test and or compression test. It is hard to interpret the results, but a garage familiar with Porsches and borescoring should be able to advise you. Another simple check (as mentioned above) is the condition of the rear exhaust tips. If it is burning oil on bank 2 then the left hand exhaust tip will be more sooty than the right hand side.
Kind Regards Lee
 
Hi all,

I have emailed Hartech and wait to see what they can advise from the dodgy endoscope photos I took. Maybe not much as the quality isn't great but let's see. I will also check out the AOS, probably using Geoff997's approach ("The easiest way to check the AOS is to remove intake tube from the throttle body. There will be obvious oil contamination on MAF etc. if the AOS is passing oil") as I don't really want to run the engine at the moment unless absolutely necessary.

Interesting, and indeed sensible, comments regarding the exhaust "tips" (excuse the pun, sorry, couldn't resist!). However, neither of them look that sooty but maybe the left is slightly more sooty than the right? Picture of left here:
s!AiTXc_fI742A2lfcPGjuNLMGpVMG
(https://1drv.ms/u/s!AiTXc_fI742A2lfcPGjuNLMGpVMG) and right here:
s!AiTXc_fI742A2lfcPGjuNLMGpVMG
(https://1drv.ms/u/s!AiTXc_fI742A2lfcPGjuNLMGpVMG).

As always, all thoughts appreciated!
Jules
 
Hi Edwill997. No news yet I'm afraid. I still have to check the AOS which I will try to do this week but I have no heard anything back from Hartech yet. I am sending them another email this morning. If that doesn't work within a day or two, I will call them.

Thanks for your interest and support! It's needed at the moment!
Jules
 
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