Coolant leak and slow speed fan not working

[SD1too]

Originally Posted by Mr Toad

The mayonnaise is confined to under the cam covers.

Thanks for this Martin. I think the question should be asked: why? If oil and coolant are mixing, wouldn't you expect the valve gear to be covered in it as well? Wouldn't this be a virtual certainty if, as you surmise, there's a crack in the head as opposed to the cam cover?

How has this car been used? Does it stand for long periods outside? The cam covers are probably the coolest part so I'm wondering whether it's condensation mixing with oil vapour. Are your breather tubes intact or have they fractured recently?

Originally Posted by Mr Toad

I have not fully drained the oil but I can see it is black no doubt coolant mixing with the oil.

Regarding this and T-Cut's post, you will need to drain the oil since he specifically states that ....

Originally Posted by T-Cut

.... it will take days to empty due to the high viscosity.

So if yours doesn't, could the black oil simply be a sign that a change is overdue?
By the way, if you have a black tipped dipstick as I do, that can mislead. Wipe it on a sheet of kitchen paper to obtain a true indication of the lubricant's colour.

As you can probably tell, it will take a lot to convince me that a head has cracked. There's always a temptation to follow a very complicated diagnostic path when most faults turn out to be very simple. Think of garages looking at a 75/ZT which overheats and convincing the owner that the head gasket has gone and the car's fate is sealed. We all know that the fan is the most likely culprit.

Simon