Oil contaminated glow plug

TAABVW said:
I've done plenty mechanicals but never had the head off a TDI. I've read internet horror stories that on these engines the head will always warp and cannot be skimmed, therefore the replacement head gasket will always leak. I've no idea how true this is and I'm looking forward to thread updates as I'm bound to have the head off one of mine one day. If the internet is right then I'd be really careful and gradual undoing those head bolts in the correct order to try to prevent any warping. Phil sounds like a very competent and able guy so he probably knows this (or knows it's rubbish) already.
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Your right there is a serious risk of warping. Audi manual specifies the bolt removing sequence. I was planning to reverse the tightening sequence, 90 degrees off in reverse sequence, a further 90 degrees of in reverse sequence, then probably remove the bolts in reverse sequence. I'll check the Audi removal sequece is the reverse of the tightening sequence before starting.

This I think is how to warp a head, fast forward to 8 minutes:

Edit: the last thing he does is cut off the cam sensor 🤣
 
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philward said:
This is the explanation I have for the glow plugs. The head heats and cools expanding and contracting along with the air in the tiny space between the plug and the head. Basically it acts like a mini pump expelling a little air up the thread and drawing it back in again as it heats and cools. If oil is puddled around the base of the plug then oil not air is drawn in.
Oil cannot puddle around plug 1, it was dry. The oil leak was at the injector harness plug so plug 3 got the most oil and was by far the wettest. Sounds like an engineering fairy story but I'm going with it.
Only the head to decide about now. I need to clean up and work out what thickness head gasket I've got and see if I have capacity for skimming. Warped heads can be avoided but I'd like a safety margin.
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Was this or all 3 plugs tight fit or the one covered in oil was sort of loose ? I'm still holding my opinion no need to take head off really on this example
 
robskiA2tdi said:
Was this or all 3 plugs tight fit or the one covered in oil was sort of loose ? I'm still holding my opinion no need to take head off really on this example
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The plugs were not fully torqued, I got them with a torque wrench set to 15 Nm. The theory was they can take 15 Nm going in so I can’t snap them at 15 Nm coming out. If the wrench clicked before the plug moved I would have had to think again.
I’ve discovered the thread is 10 * 1 the same as brake pipe fittings. I have brake fittings in there to prevent dirt ingress. Non of them appear particularly tight and can rattle a bit.
 
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BigBang said:
Also it can be used also as a guide how to bend/crack cam shaft 😂
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I didn’t watch it all, I’m going to check this but I think I have the cam positioned so all valves are closed. I was very cautious but I have been able to turn the crank without contacting the valves.
Ill check this morning, it is a useful position and it will be impossible to bend the cam when removing or fitting.
 
philward said:
The plugs were not fully torqued, I got them with a torque wrench set to 15 Nm. The theory was they can take 15 Nm going in so I can’t snap them at 15 Nm coming out. If the wrench clicked before the plug moved I would have had to think again.
I’ve discovered the thread is 10 * 1 the same as brake pipe fittings. I have brake fittings in there to prevent dirt ingress. Non of them appear particularly tight and can rattle a bit.
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what i've meant by that was that is plugs were not tight then thread its easy passage for oil being dropped on top of plug from enywhere while engine is taken off from chassis and then stored and transported
 
philward said:
This is the explanation I have for the glow plugs. The head heats and cools expanding and contracting along with the air in the tiny space between the plug and the head. Basically it acts like a mini pump expelling a little air up the thread and drawing it back in again as it heats and cools. If oil is puddled around the base of the plug then oil not air is drawn in.
Oil cannot puddle around plug 1, it was dry. The oil leak was at the injector harness plug so plug 3 got the most oil and was by far the wettest. Sounds like an engineering fairy story but I'm going with it.
Only the head to decide about now. I need to clean up and work out what thickness head gasket I've got and see if I have capacity for skimming. Warped heads can be avoided but I'd like a safety margin.
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I'm not totally convinced this would happen unless the engine was unused for a really long time. In normal use if the glowplug wasn't tightened properly you might get a tiny amount of oil seeping down the threads. But if that was possible it would be quickly blown back out as soon as the cylinder went through a few compression cycles and was run. If the glowplug was wet with oil, it's happened since the engine was last run/tested, so in a relatively short space of time. Im not sure were the oil ways are in the head but could there be a crack within the head by the hole for the glowplug allowing oil out? I'm not sure if thats plausable or not to be honest, its very wierd the amount of oil on the glowplug
 
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I've now got a clear view of the head. It is a surprisingly deep box shaped casting. Heads I have dealt with in the past have been much longer. I feel that it would be difficult to warp something this shape so as soon as I have a mate to hang on to the engine its coming off.

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What are the two tubes sticking up in the corner and middle, like guide sleeves?
Also to take head off do you have tonremove the injectors?
 
@CrispyEdd I believe the head would come off with the cam, rocker shaft and injectors still in place.
I think the guide tubes are guide tubes. Was it yourself who asked about the engine stand. Ill get one ordered and post how I get on.
 
Yes i was asking about the stand as I have a good engine here that just needs a skim. Never taken engine apart but fancied doing serious garage fettling over winter for fun see if I could get it back together..
 
CrispyEdd said:
Yes i was asking about the stand as I have a good engine here that just needs a skim. Never taken engine apart but fancied doing serious garage fettling over winter for fun see if I could get it back together..
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Stand on order, for some reason I got a 8% discount. Every penny helps 😊
 
CrispyEdd said:
Do you have to fit a new gasket anyway or fresh one shall i say
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It 100% needs a new gasket. Which one I don’t know yet because the old is covered in crud.
There is a range of sizes, perhaps 4. It is however the thickest head gasket I have ever seen.
 
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