14-04-2014, 10:35 AM
XUDs have a bad reputation due to people not being able to follow simple instructions and motorfactors supplying incorrect parts, looking for a quick buck.
They were supplied from the factory with multi layer steel headgaskets, PSA recommended that the coolant be changed every few years or so (fair enough, ally head, steel block, good practice) and garages didn't bleed them correctly due to the header tank being lower than the level of the bleed points (they didn't follow the manual that would have said to make it higher than the bleed points, or pressure bleed it), then gave it back to the customer who didn't notice the temperature gauge pinging off the "f*cking hot" mark, drove it back to the garage with no water, warped the head... Then the garage changes the head gasket, because it's guaranteed to be blown after getting that hot...With some shitty fibre gasket from the motorfactor, doesn't skim the head to keep costs down, then it's just a recipe for the gasket going AGAIN!
They are quite sensitive to heat, if you allow them to get hot, they will start blowing gaskets, that's just the joys of having an ally head on a steel block with precombustion chambers - they put an incredible amount of heat into the cylinder head and have to be kept cool, if you don't keep it cool, it'll just warp the head and blow the gasket, the localised heating is so intense. They don't give the same instant obvious issues of a petrol with no water in, i.e. power dropping off, instant boiling over of the coolant... That all happens with such vigor... An XUD will plod along, with water boiled off in the cylinder head, airlocked to shit, with no cooling, but won't spray everything out the header tank, but by that time it's too late and you've f*cked the head gasket.
The real problem is that people assume the temperature gauge is just a reading of how hot the entire engine is, not an average thing - if the engine was actually still filled with coolant around all of the bits in the head when the gauge is reading 100*C and not boiled off, it would actually run fine, it's just that generally if the gauge is reading 100*C then there is a serious problem and it'll have boiled off the coolant - meaning that probably inside the head it's coming on 150*C with essentially no cooling, but the gauge is happily reading an average of 100*C...
Also people driving round with corroded radiators doesn't help at all, the stock radiators do corrode out - essentially they end up driving round with no cooling system.
I've had an XUD for ~ 6 years now, I've never *blown* a head gasket, I've stretched head studs, had coolant blowing out the header tank, but never actually destroyed the gasket as such, every time you retighten the studs, it's fine again... Essentially an XUD is unbreakable if you don't overheat it.
TL;DR: Do not let them get hot, they don't give much warning and are a bit sensitive to people who assume they're unbreakable.
They were supplied from the factory with multi layer steel headgaskets, PSA recommended that the coolant be changed every few years or so (fair enough, ally head, steel block, good practice) and garages didn't bleed them correctly due to the header tank being lower than the level of the bleed points (they didn't follow the manual that would have said to make it higher than the bleed points, or pressure bleed it), then gave it back to the customer who didn't notice the temperature gauge pinging off the "f*cking hot" mark, drove it back to the garage with no water, warped the head... Then the garage changes the head gasket, because it's guaranteed to be blown after getting that hot...With some shitty fibre gasket from the motorfactor, doesn't skim the head to keep costs down, then it's just a recipe for the gasket going AGAIN!
They are quite sensitive to heat, if you allow them to get hot, they will start blowing gaskets, that's just the joys of having an ally head on a steel block with precombustion chambers - they put an incredible amount of heat into the cylinder head and have to be kept cool, if you don't keep it cool, it'll just warp the head and blow the gasket, the localised heating is so intense. They don't give the same instant obvious issues of a petrol with no water in, i.e. power dropping off, instant boiling over of the coolant... That all happens with such vigor... An XUD will plod along, with water boiled off in the cylinder head, airlocked to shit, with no cooling, but won't spray everything out the header tank, but by that time it's too late and you've f*cked the head gasket.
The real problem is that people assume the temperature gauge is just a reading of how hot the entire engine is, not an average thing - if the engine was actually still filled with coolant around all of the bits in the head when the gauge is reading 100*C and not boiled off, it would actually run fine, it's just that generally if the gauge is reading 100*C then there is a serious problem and it'll have boiled off the coolant - meaning that probably inside the head it's coming on 150*C with essentially no cooling, but the gauge is happily reading an average of 100*C...
Also people driving round with corroded radiators doesn't help at all, the stock radiators do corrode out - essentially they end up driving round with no cooling system.
I've had an XUD for ~ 6 years now, I've never *blown* a head gasket, I've stretched head studs, had coolant blowing out the header tank, but never actually destroyed the gasket as such, every time you retighten the studs, it's fine again... Essentially an XUD is unbreakable if you don't overheat it.
TL;DR: Do not let them get hot, they don't give much warning and are a bit sensitive to people who assume they're unbreakable.
