Cooling System - advice please

[db.08]

I'm just after a bit of advice re engine temperatures.
Whenever I drive my car (V12 auto) I don't seem to be able to rely on the temp gauge as it's a bit erratic (as are the other gauges too - is this normal?? Speedo seems to be out, oil pressure gauge is all over the place).
But when I park the car, the cooling fans run for quite a long time after the engine is turned off and there is an incredible amount of heat under the bonnet.
I know there isn't much room under there, but does anyone know if this is normal?
And also, has anyone ever seen or heard of some form of venting in the bonnet that might extract hot air?
I'd hate to do it some damage.
Thanks.
Dave

[Bjorn V]

I'm not an expert, but if all, or several of the gauges are behaving strangly, perhaps there could be an electrical problem in the instrument binnacle itself?

As far I have understood it the temperature gauge i generally believed to function well. If it´s showing a high temperature, it probably is to high.
But the best way to invesigate would probably be to meassure the temperature on the hoses that comes from the enginge. I believe this could be done with some infra-red device.
The oil pressure gauge on the V12-cars is however wery unreliable.
That the electrical fan is running a while after a run would be considered normal I think.
How long is the fan running post shut down?

The Jaguar V12 does not like to overheat, so cooling probems shoud be taken serously.

[db.08]

I'm not an expert, but if all, or several of the gauges are behaving strangly, perhaps there could be an electrical problem in the instrument binnacle itself?

As far I have understood it the temperature gauge i generally believed to function well. If it´s showing a high temperature, it probably is to high.
But the best way to invesigate would probably be to meassure the temperature on the hoses that comes from the enginge. I believe this could be done with some infra-red device.
The oil pressure gauge on the V12-cars is however wery unreliable.
That the electrical fan is running a while after a run would be considered normal I think.
How long is the fan running post shut down?

The Jaguar V12 does not like to overheat, so cooling probems shoud be taken serously.

Thanks Bjorn
It's good to know that the oil pressure gauge is notoriously unreliable. That explains a lot.
The fan is running for several minutes after shut down, but if I lift the bonnet there is an awful lot of heat in there, so I do need to double check that all is ok.
It may mean a trip back to my local friendly Jaguar service centre ($$$) soon as I'd hate to do any damage.
For Australia, I'm surprised that there aren't some form of vented bonnets available to dissipate the heat, given how full the engine bay is so not much room in there.
Twin thermo fan conversions are popular here though, so I may need to investigate that.
Dave

[Bjorn V]

I agree that it would be wise to do a serious check that all is OK. I think that could be normal for the fan to run for a good while if you are driving in really warm temperatures. If the outside temperature is not that high, a fan running for several minutes it could indicate that the engine is a bit to warm.
I believe that I´ve heard of vented bonnets for XJS, but dont think I ever seen one.
On the other hand, really warm temperatures is not that common here in Sweden, so the problem is a bit smaller here.

A cooling system upgrade could be a good idea, but I think that the first move on the cooling system should be to get the standard system up to perfect nick.

It is a cramped space under the bonnet of a XJS V12 car. I once heard this joke:
-How did they do quality check on the end of the XJS production line?
-There was an old woman, who poured a large bucket of water into the engine bay. If any water dribbled out below the car, something was missing.

[db.08]

Haha, very funny.

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