Oil contaminated glow plug

Howey said:
Oil won't have come from inside out it will be an external source
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This is what I’m hoping. I thought somebody may know how it could get past the threads into the gap between the threads and the seat.
3 was dripping, 2 looked damp and 1 as I would expect, dry. Thanks for the redponse 😊
 
It wouldn't be oil as such leaking past the threads and up the shaft of the glow plug it would be carbon with would likely solidify and make life hell, the same way blow by gasses around injectors on more modern stuff occurs. The oil has been sat around the glow plug and leaked downward as the plugs been removed
 
George Hogg said:
That whole glow plug looks covered in oil from the top down.


G
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Yes, any idea how it got there? Your observation is the same as mine. There has been an oil leak at the rear of the engine so 3 would see most oil.
I don’t think a previous owner would have dipped one, wiped one and fitted one dry.
 
Howey said:
It wouldn't be oil as such leaking past the threads and up the shaft of the glow plug it would be carbon with would likely solidify and make life hell, the same way blow by gasses around injectors on more modern stuff occurs. The oil has been sat around the glow plug and leaked downward as the plugs been removed
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I would buy that except I have soaked 1 and 3 in penetrating oil before attempting to remove. I don’t think it was penetrating oil and 1 was dry. Thank you for your input, much appreciated. Tommorow I will get oxy to the issues down the back of the engine. Then weather permitting later this week I will remove the head and investigate.
 
philward said:
I would buy that except I have soaked 1 and 3 in penetrating oil before attempting to remove. I don’t think it was penetrating oil and 1 was dry. Thank you for your input, much appreciated. Tommorow I will get oxy to the issues down the back of the engine. Then weather permitting later this week I will remove the head and investigate.
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Oil will not come out of the cylinder unless the engine is proper goosed!
It's always best practice to blow out the glow plug recess before removing the plugs as this stops debris failing into the cylinder and any misunderstanding about any evidence therefore found, appreciate not many folk at home would have a compressor thou!
 
Howey said:
Oil will not come out of the cylinder unless the engine is proper goosed!
It's always best practice to blow out the glow plug recess before removing the plugs as this stops debris failing into the cylinder and any misunderstanding about any evidence therefore found, appreciate not many folk at home would have a compressor thou!
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I’ve got one and know to blow out. On this occasion I brushed out. Didn’t want to blow muck around inside the back if my old Merc.
 
All let’s end this now. Thank you very much for your contributions but the only way I am going to understand what I’m seeing and have never seen before is to take the head off and investigate.
I will report my findings.
 
philward said:
All let’s end this now. Thank you very much for your contributions but the only way I am going to understand what I’m seeing and have never seen before is to take the head off and investigate.
I will report my findings.
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I think your mad but also intrigued if you do find anything a miss, I highly doubt it but at the same time always open to learn new things! Best of luck!!
 
BigBang said:
If he is not sure engine is OK, why not to do a deeper check?
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Just my opinion.

It's every individuals choice and he's certainly more than capable of doing the job competently.

I look forward to the thread update and certainly hope it's as pain free as possible!
 
A2Steve said:
Just to confirm, the following checks were done before I removed the engine (taking an engine out is no walk in the park and so I wouldn't bother removing a bad one, let alone sell it)

- checked it run up to temperature
- checked it wasn't smoking
- used a sniff test device once warm to check if the headgasket was ok
- driven around the estate to ensure it pulled well without going into limp

Other than that there is very little else I can do on a breaker to ensure the engine is ok.
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You can't do anymore than that for sure, any engine can go pop at anytime, thats cars and it's always gamble not sure there's such thing as a perfect engine second hand. My engine from you is doing great guns, it's the same with all second hand parts it's a gamble.
 
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.
 
TDI hrad can be skimmed. There are various thickness head gaskets available to compensate that 😉 I did this on my R5 recently...
 
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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