tav12

P400 water pump - this is not offical info, use at your own risk and judgement

Description	Lamborghini part number	OEM manufacture part number	alternate part	alternate part number	approx cost
water pump/oil pump oil seal	GN-03760 008611704	Gaco DPSM 17307, 17x30x7mm	17 x 30 x 7 mm buna N seal		$10
water pump shaft seal	GN-00632 008611703	mechanical seal GUARNIZ. B-25342
water pump shaft seal face washer	MW-00396 1700396	12mm x 34mm x 4mm, micro polished steel 12mm x 30mm x 4mm, micro polished steel
shaft seal backup washer	MW-03593	19.1mm x 34.8mm x 2mm, flat steel
impeller nut, brass, acorn	DN-00487	10mm x 1.5 thread x 17mm hex x 17.5 height
impeller lock washer	RFN-00987	tang to impeller slot, bent over lock nut, .8mm thick, 10x23
impeller key, steel	LN-00699	4mm width x 4mm tall x round ends
temp sender	MB-01333 001801333	Jaeger, France, 14, 12v, M16x1.5 , H7, 82405
water "Y" O-rings - 2ea	GN-01236 008602303	ANELLO D.24 OR 132	24mm
water hose	MW-03761
water pump housing gasket	MW-00392
water pump base to oil drive gasket	MW-03592

Notes	Graphics
Cross section view of a P400 water pump. The stack height of all the pieces in relation to the oil pump extension shaft is critical. The gasket thickness is critical. Impeller alignment on the shaft is critical. The area of the steel shaft in the water seal section, which will corrode, is not critical to the mechanical shaft seal. The area of this steel shaft in the Gaco lip seal area is critical to the sealing of oil. additional information - 1) Oil seal installs with lip toward oil pump. This lip seal keeps oil pump oil from leaking.Generally requires a "bullet shaft protector tool" and lubrication to install partially assembled water pump on engine to avoid damaging this oil lip seal. 2) Water must not be allowed to leak in 3 places: - behind the polished washer (MW-00396) as it butts up against the back of the impeller - across the polished washer/seal face - OD (35+mm)of the spring loaded, elastomer encased, water pump seal (GN-00632)or (08611703) in the water pump housing ID (35mm). 3) the seal face, micropolished washer MW-00396 was a large34mm diameter in early Lambo pumps and slightly smaller 30mm in later versions, but is not currently available in either diameter. The reduced diameter of the newer seal face washer is not a problem, but any change in thickness will create a problem. If you were to re-grind/repolish the face, you would want an appropriate shim and positive sealing for the new shim.