Engine block drain tap

[eddiecross]

Hi,
I am draining the cooling system on my S1 4.2 to refresh for the winter (1st time properly since I bought it).
rad out
header tank out etc.

List so far is:
New hoses and clips
Thermostat
Header tank.
I have a S2 Otter switch that I am going to wire to a relay with a manual override switch
Original fan and shroud (ebay/swap meet)
Stone guard (mine was missing)

question....
The drain tap on the block is stuck shut. Do I need to free it off or unscrew it?
i.e does coolant get trapped there or did it all drain out once the bottom rad hose was pulled off the water pump?

Thanks
Eddie

[abowie]

The tap is lower than the water pump so there will still be some coolant in the block.

Unscrew the tap from the block.

Secure it in a vice. Take the split pin out from the bottom of the tap spigot. The spigot is tapered, so you can gently hit it with a hammer and drive it out. Be careful how much force you use as it's probably brass. Some heat from a propane torch will help.

Once it's out clean it up and reassemble.

[eddiecross]

Many thanks Andrew. Exactly what I wanted to know.

Regards
Eddie

[44DHR]

Eddie, the original Jaguar drain tap is made of brass, including the tap handle.
Under no circumstances try to twist the tap handle if it is tight as it will surely snap off as it is integrally cast with the spigot passing through the tap body. The tapered spigot has a hole through it to turn in a matching taper in the body of the tap. The spigot is pulled downwards by the spring under the tap to provide a watertight seal. When the handle is turned 90 degrees, the hole in the spigot lines up with the inlet and outlet ports in the tap body to allow the water to flow.
Often the two tapers will jam in a form of interference fit. As Andrew says above, the only safe way is to remove the tap, disassemble the spring assembly and tap the spigot out - often with a bit of assistance of a gas torch. The original shape “angle nose” drain taps are becoming hard to find these days.
Regards,
Dave

[eddiecross]

Thanks Andrew and Dave.
Tap removed. About 2 litres of water came out so needed to come off.
Tap now stripped cleaned, greased, reassembled and refitted to the block with a new fibre washer.

Jobs a goodun.

Eddie