Hi Richard, Garry and all
OK, so for those unfamiliar with the S3 V12 cooling system, a few comments and clarifications.
Firstly, all that Marek says is absolutely correct. Just to add to that, the V12 has a habit of silting up. To overcome this, ensure you use a good quality coolant with anti corrosion qualities and suited to Alloy engines. There was a general lack of understanding of Alloy engines at launch and dissimilar metal corrosion, amongst other things, tended to set in and this is what gives rise to the ?Crud and Sediment? Marek refers too. Over a long period of time, this can actually reduce the quantity of coolant and also prevent much of the surface area inside the engine from coming into contact with a flow of coolant, both bad for the engine generally.
A flush, normally in the opposite direction to flow can help this and is good for any engine, but years of neglect will mean that a flush is only partially effective. The sheer size of the system is also against you since the flush will take the easiest route and it is difficult to get any kind of pressure to many parts of the system. This is what I discovered when stripping my engine and eventually led to my sourcing another block (to be accurate, my very experienced Engine builder did all that). I have photos of the old engine showing the amazing crud build up and one head simply refused to move. Nevertheless, a flush can help ? use a hose and run until the water runs clean, you could be a long time doing it?. (beware if you have water restrictions in your state ? Garry, are there restrictions in Canberra on garden hoses right now?
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Check the Header tank, this is steel and whilst alloy ones can be found they are harder to source than for the six cylinder cars and quite expensive. There is an overflow and if you do overfill the system, this will leak for a couple of outings, giving the impression of a failure ? you then refill, it leaks, you think there?s a problem and refill again?.. There is no overflow bottle in the system unless modified, so the coolant just dumps to the floor.
There are two cylinder heads, hence two thermostats (one each mounted at the forward end of the pipes which supply coolant around the inlet manifolds, directly forward of the carburettors), one temperature sender (to the instruments, located adjacent to the Right Hand Thermostat), one temperature switch (Otter Switch, located in the ?Tee? at the base of the pipe from the Header tank to the Radiator outlet, central to the radiator and between the horns). There are two fans, (electrically driven and controlled by the Otter switch), one Fan relay, the radiator (of course) and the heater matrix and fan in the Heater unit on the LH engine bulkhead. There is also an oil cooler, which is cooled by the flow of cooled water straight from the lower radiator outlet (not air cooled) and, not related to the engine, an air cooled oil cooler integral to the radiator but fitted only to Auto cars and used to cool the Auto gearbox. This takes some of the space used in the manual car radiator, possibly reducing cooling effect slightly. There is one water pump, of differing design between early and late cars. Early pumps are hard to source replacements for, but can be rebuilt.
The system has an amazing amount of hoses (and associated clamps), which should be inspected and maintained. These should be good quality cotton reinforced, not Kevlar, which were sold some time back as being wonderful ? they weren?t. There are also many places for air to hide on filling. Suggest you run the engine immediately after a refill, briefly to reduce heat build-up, but to allow the fluid to reach various areas of the engine, you can consider doing this without the rad cap fitted, but don?t let heat build up ? probably no longer than half a minute or so. Then check and top up. Don?t remove a cap from a hot, pressurised system unless you like being scalded badly, it is possible but must be done with great care. Mareks? idea of raising the nose and squeezing accessible hoses during filling are good ones. With all the hoses and gaskets in the system, there are many places that leaks can occur, check under the car for drips.
My car has coped well so far with Melbourne temperatures and traffic even up to 40 degree plus temperatures. However, I have an Alloy radiator, an engine which was chemically cleaned and flushed, a modern replacement for the Otter switch which opens at 75 degrees Centigrade, modern fans in a custom housing, each powered by an individual, modern relay. Wiring was replaced and modified for the new fans and relays. My early water pump was rebuilt by SNG Barratt. Also I ensured the fairing behind the grille, designed to direct all air through the radiator, is present and that there is a foam seal between it and the bonnet, to maximise the flow of air in the correct places. Don?t mount the rego plate in front of or on the grille. If like us in Victoria, you are forced to have a rego plate, use the smallest you can and mount it slightly forward of the grille, as low as possible without totally obscuring the chin mounted intake of the Series 3.
Other overhearing issues come from mixture and timing issues, which I won?t cover, plus of course the drive belts at the front of the engine, two are required to drive the Alternator and water pump, another for the Power Steering , one each for Air-Conditioning and the emissions Air Pump, if fitted. Of these, the two driving the water pump must of course be tight for good coolant flow. Due to the options, some cars have pulleys with unused belt grooves.
As Pete says, get the parts manuals, the OTS version has been reprinted by Brooklands Books and is the same as the FHC except some body/trim details. There are several sources for Electronic versions, officially produced and sold by Jaguar Heritage. I think this Forum also has the manuals in the Knowledge base. Obviously, get the workshop manual too; even if you don?t work on the car yourself, it may help your mechanic, especially if you break down away from a Jaguar specialist!
Hope all this helps. It?s a big system, simple and traditional in theory, but complicated by size and access, not to mention the very real possibility of poor maintenance at some time during the life of the car.
Regards,
Simon
