Originally Posted by m37charlie

I'm sorry, I don't understand what you are saying. What is "GO"?
What do bad injectors (usually caused by dirt or water in fuel, not high sulfur) have to do with low compression (usually caused by bad rings or valves)?
Could GO be gazoil? Accumulation of fuel is definitely caused by bad injectors unless you have a Euro 5 or 6 engine in which case if it has "in-cylinder regeneration cycles" it could be a symptom of a malfunctioning emission system (extra fuel injected in exhaust cycle to burn soot out of DPF).
If your Defender takes DEF it also probably has a DPF. You DO need to buy the euro diesel unless you delete your emission system which usually also requires software changes. There are many vendors in the States that supply this for US diesel pickups but I had to look hard for someone that can do it for my diesel X5. I don't know if this is available in Europe due to EC wide inspection requirements. Alaska for example does not require emission inspections, most of California (but not all!) counties do require it, also many other states. Canada not so much.
Roro, it is possible that your engine was ruined by the engine's attempt to follow the emissions software. Usually damaged injectors due to dirt/water will produce gradually increasing easily recognized symptoms like missing, loss of power and lots of black and/or white smoke. Which will further instigate the emissions system to do more and more soot "burnouts".
Iran and parts of Africa have some of the highest sulfur diesel in the world - some places 10000 ppm! This will quickly damage/destroy a DEF/DPF type emissions system which will cause various (bad) effects on the engine as "side effects". As I have repetitively written previously, the sulfur does not damage the engine directly (except that it uses up the alkalinity of the lube oil much more quickly and then acidity can cause internal engine damage if the oil is not changed/replaced with high alkalinity oil [ACEA E4/MB228.5]) but it will eventually destroy the emissions system at a rate dependant on sulfur level. Then the "side effects" can destroy the engine.

Charlie

Originally Posted by roro

I'm going to try what my mechanic told me:
Bad diesel causes dammage to injectors first.
Then bad injectors fill cylinders with diesel and this causes bad lubrification then bad compressions.
Sorry for these incomplete explications because I don't know english terms for them.
I don't know if my Def TD5 is Euro 5 or 6 , it was made in 2006.
RR.