XUD head gasket symptoms?

[bertiewhite]

Whilst working away from home my wife told me that just lately my XUD engined Partner had been losing power and would cut out. On my return I found out that it wouldn't idle. Suspecting that the car had been run low on fuel, I changed the fuel filter & put some injector cleaner in the tank but it was no better. I managed to get the engine to idle by adjusting the accelerator but it's lumpy as hell and some other symptoms have developed.

As I've had problems with both water & air in the diesel, I thought the lumpy idling was down to one or both of these again but I have also noticed that there is a faint trace of vapour/smoke coming from behind the rocker cover and the engine is chucking out more blue/grey smoke from the exhaust than ever (previously only on start up). Also, I'm sure that engine is running hotter than usual as well. Because of the smoke from behind the rocker cover & the engine temp, I'm beginning to think it's the head gasket (it did overheat slightly when towing a few months ago) and I'm almost hoping it is because I was used to changing them on my k-series rover but I thought I'd ask what you guys thought. The only thing I would add is there is no trace of mayonnaise in the coolant.

[Peter.N.]

Head gasket failure will result in pressure in the cooling system which will eject water from the filler cap or the overflow pipe. XUD heads often crack if they have been boiled. If you are not loosing water its unlikely that the gasket has failed. Mayonnaise in the coolant would normally indicate that the engine had been running cool rather than hot.

I think the problem is more likely to be due to air in the fuel system, has the fuel filter been changed recently? if not that should be your first port of call, if that doesn't cure it check all the pipe connections including the injector leak off pipes.

Peter

[bertiewhite]

Yes, I've changed the fuel filter and checked that the housing/top has sealed. I've also been checking for leaks in pipes but I have had problems with leak off pipes in the past although that resulted in a complete lack of power throughout the range, not just at idle. I'm curious as to what the vapour coming from the rear of the rocker cover/manifold area is?

[BX]

Obviously the first thing to rule out is air leaking into the fuel system. Is this perhaps a van with the DW8 engine fitted with the Lucas epic pump? Does it have the oval fuel filter housing? Because there is a purge outlet on the filter housing that goes to the leak off and return pipes it can happen that a poor leak off pipe can allow air ingress. There should normally be clear pipes going to and from the injection pump. Is there any air bubbles to be seen. A small amount is often no harm.
The horrible Lucas contraption if it goes wrong is another story covered on various threads.

[bertiewhite]

It's got the XUD engine with round fuel filter. I'll check all the pipes again and I could try substituting some clear pipe but like I've said I have had problems with both air in the system & water in the fuel before but the symptoms were simply a huge lack of power throughout the power range with air and misfiring with water whereas now it will only idle (roughly) because I've adjusted the accelerator cable and it runs with a slight misfire at higher revs. Plus there's the massive amount of blue/grey smoke whereas I only had a small amount of blue smoke at start up when running ok and lots of white/grey smoke with water.

[bertiewhite]

I've just had an idea - I work on aircraft and when we've had leaks in the pitot-static system (air getting out) we use a fluid around unions which show bubbles escaping. If I sprayed something like WD40 around the fuel pipes, would this work in reverse by showing an change in idling?

[Northern_Mike]

I've just had an idea - I work on aircraft and when we've had leaks in the pitot-static system (air getting out) we use a fluid around unions which show bubbles escaping. If I sprayed something like WD40 around the fuel pipes, would this work in reverse by showing an change in idling?

Yes...