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Off with its head


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Well, I've put around 100k miles on my 300Tdi over the last eight years or so and then strapped a VGT to it and found up to 2 bar boost at times. Not surprisingly, months later I found it was leaving a cloud of white/grey smoke if it was allowed to idle and then revved - such as at junctions. It's also been giving gradually worse mpg over the years. Big tyres + autobox + VGT + lead foot seems to give 18-20mpg around town which is expensive.

I took the head off this evening and found the following. The block didn't drain fully so some water got into the bores, particularly #3 and #4. I soaked this up, turned the engine over a few times and then aggressively polished the bores with a light oil and a clean cloth - the water was in there for 5 mins or so. I have my own opinions which I'll reserve for now, I'd be interested to see what others think is going on. Sorry for the large photos, I need to show the detail:

A number of small deformations on #1 piston crown:



and water marks on the bore of #3 cylinder only.





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No1 piston looks ok apart from the pitting at around 2 o-clock.

No3 bore is water stain, and the formation of the stain seems to indicate that droplets form while the engine is off, so perhaps reversed pressure as the engine cools down.

There seems to be a fair few posts across the various websites about white smoke at idle/pulling away from lights. Have/will you have the head crack tested?


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Yup, you've mirrored my thoughts. The bores look good, the diamond honing marks are still present even on the thrust side so oil changes at 7k miles have been doing their job. The pitting on the piston is restricted to the fuel spray star area so suggests the injector is hosing in that region - IIRC Tony Cordell melted a piston through the same fault further down the line?

The water marks are more troubling to me - the gasket surfaces looked fine and there's nothing immediately visible on the head. I'll get some dye-pen and look for cracks.

Does anyone have a Tdi piston loose and can measure the height difference between no 1 (top) and no 2 ring grooves for me please? I'd like to keep the pistons in mine if possible.

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Well, I didn't need the dye-pen. The head showed carbon on all the fire rings:


and cleaned up well:


Number 3 appears 'different' but not steam cleaned like you'd expect with a coolant issue. Anyway, I looked a little closer at #3:


Two cracks, one from the heater plug hole and one between the injector hole and the inlet valve.

#2 and #4 also show the heater plug crack:


It looks like I need a new head, but that's not "economically attractive" at £300 - anyone got any bright ideas?

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Realistically you have three options in order of increasing cost and (probably) decreasing risk:

  1. Live with what you have
  2. Chance a secondhand head
  3. Splurge on a new one

but you have probably worked that out already yourself!!

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I would be inclined to have your current one pressure tested to see if the cracks that you have identified make any difference to the operation of the head.

I would be more concerned about the carbon trace between no2 and the water way. It looks like the fire ring has not held up but the next seal has not been breeched.


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Yes, I'd noticed the leaking on #2 as well. Presumably that would be fixed with a new gasket though. My current thoughts are:

  • £100 second-hand head could be worse than the one I've got - why was it taken off and reconned/skimmed/cleaned? They generally claim to be 'pressure tested' but where's the comeback if it turns out to be duff?
  • £275 'new' head on Ebay is £20 less than a head from Turners (and £5 less than a Paddock head), which would come with a guarantee.
  • My head might not be a problem, but I'd have to test it to know
  • The cost of testing would eat into the ££ for a new head, which would probably turn out to be necessary anyway.
  • From the bore marks, water has been getting into #3 from somewhere - if it's not the head then it's via the head gasket, and that looks strong on #3
  • Using the engine as its own test bench, it looks like there's a crack to the water jacket somewhere in the head


  • I probably need a new head

I'd rather give my ££ to Turner than Paddock but I don't see that I'd get £20 more value (and I'll be passing Paddock in couple of weeks, so I'd save the postage). Some forumeers have had 'performance' heads before and been underwhelmed so I don't think I'll go that route. Is there anyone I've not considered?

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[*]£100 second-hand head could be worse than the one I've got - why was it taken off and reconned/skimmed/cleaned? They generally claim to be 'pressure tested' but where's the comeback if it turns out to be duff?

I made that mistake... Its not until you get it home and attack it with some degreaser you really start to realise you screwed up :ph34r:

Anyway heres my 200tdi head with similar cracks. Although it was running fine before i removed the head.


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I "borrowed" some dye-pen and found that the cracks I could see with my eyes are still there when tested...


The consensus is that I need a new head (... on the engine, that is). I'll pressurise the water jacket to see if there's any bubbles but, to be honest, the water stains in #3 bore are enough to tell me that water's been getting in somewhere.

The good news is, piston #1 shows some distress marks where the fuel injector has been hosing, but no cracks so that will run again:


Where's best to get a new head from? My options look like being:

ACR: £410 + VAT

Turner: £295 + VAT (or £410 with valves etc)

Foundry 4x4: £276 incl VAT (via Ebay)

Craddock: £250 + VAT

Paddocks: £245 + VAT

A "performance" Turner head at £495+VAT is way out of my league. Any other peddlers of quality merchandise that I've forgotten?

Dave - I've PM'd you.

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