broke down...engine blown? UPDATED WITH PICS

[paulandchez]

Defo did not have old oil in. However, whilst I was in France, I had an oil leak/burning oil which meant that over 2000 miles, I put about 7 litres of oil in. The only oil I could get was stuff for modern engines too, but didn't have mush choice. When I got back I replaced the rocker seals which seamed to be where the leak was coming from.
Following my final trip, I noticed there was oil on the road where I was parked before I set off. There is also a chance that the light came on when I was on the motorway, but due to my seats and the steering wheel I have, I may not have noticed it.
So, potentially what has happened is the oil has leaked again but this time to the point where there wasn't enough.

The pics aren't great but the cam lobes are scored quite deeply

[Atomic]

That's not failed because it ran out of oil - it would seize the bottom end way before doing the pistons. As SilverBullet said, it's failed because it was far too hot - that's why the pistons are done-in, and the oil being too hot gave sod all oil pressure.

Problem on these is the oil switch is only a 4-6psi switch, so by the time the light comes on if you are driving at speed it's too late, hence they went to the dual system on later vehicles.

Hot running is only ever due to cooling system fault, over-advanced timing, or lean running. It doesn't look like it has been running lean, so was the cooling system intact, including flaps, and what was the ignition timing?

[silverbullet]

I can only see as I find. Was this engine a rebuild thats failed or an old engine? I would guess the latter, hence my comments about running on old oil (in the past)
Any oil put in since then is irrelevant, the components would all be past their best due to lack of oil film strength keeping the surfaces apart.

[paulandchez]

The engine was apparently a rebuild in 2006. I only bought the van in 2013, but there is a receipt saying it was a rebuild. I was on the motorway at the time doing about 60. Cooling system was intact (as far as I knew) but the thermostat failed at some point (only found this when removing engine, but the flaps were in the "correct" position if you know what I mean. Timing was set at 8 BTDC

[silverbullet]

Thermostat? I guess you mean for the chokes?
A "rebuild" back in 2006 could mean anything. There are enough shady outfits re-using parts that I wouldn't even use as ballast but are still charging hard money.
Without a fully itemized bill any rebuild is suspect.

[Atomic]

This is nothing to do with any possible parts quality - it has been running hot, pure and simple, and that is always an ancillary issue - cooling, timing, mixture. The thermostat has nothing to do with the chokes. - it controls the cooling flap position. It "should" fail safe to open flaps, but doesn't always. If the left flap is not sitting down fully then it doesn't direct the full amount of air through the oil cooler, so the oil will run hot. Since a large propotion of the cooling on these is through the oil, if the oil gets hot then the whole thing gets hot and it will kill it eventually. Are you quite sure the flaps were open fully?

[paulandchez]

Atomic is right, thermostat controls the flaps. When I fitted the new stat, it was genuine vw one and flaps worked great. But after the event when I noticed it had broke, flaps were in right position but not necessarily fully down