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1993 NAS Defender 110 Oil Line Upgrade
This Defender 110 has come to us for some upgrades and repairs. It has 135,000 miles, is over a decade old and it still running to original oil cooler lines. They are cracked, dry rotted and a ticking time bomb, if not for a vehicle fire, at least a road trip stopping oil leak.
The design flaw of the factory oil cooler lines is that they run far too close to the RH exhaust manifold. As you can imagine the exhaust manifold gets smoking hot and these rubber lines, with no heat protection are no match for that heat and abuse. The red arrows point to the oil cooler lines in this NAS 110.
The first step is to remove the clutch fan and the radiator shroud. This gives you a nice open place to work. Next disconnect the oil cooler lines from the radiator as indicated by the purple arrows. Oil will leak out, so be sure to have a drip tray handy.
Then remove the oil filter and the oil filter adaptor ring and remove the entire oil cooler line rats nest through the bottom of the Defender in one piece. You will end up with what you see above.
Strip down the oil cooler lines and fittings until you are left with only the adapter ring, as seen above. The oil lines and fittings will not be re-used. Only the adapter ring shown above will be re-used.
Then remove the adapters from the radiator itself. There are 2 as shown by the purple arrows.
These are the adapters once you have removed them from the radiator. These will not be re-used.
Next install the 2 adapters with the copper crush washers into the oil cooler adapter.
Once they are installed the oil cooler adapter will look like this (see above).
Next take the 90 degree fitting and apply some pipe tape to the threads. Then install it into the top opening of the oil cooler in the radiator as shown by the top yellow arrow. Then install the straight adapter into the lower radiator opening, and use pipe tape here as well. Then install the lower oil hoses straight end onto the lower adapter as shown by the lower yellow arrow.
Next install the oil cooler adapter ring back onto the engine the same way it came off and install the oil filter. Now connect the 45 degree fitting to the rear output and the straight fitting from the top hose to the front output as shown above. It is best to leave the lines loose until everything is where you want it, then tighten all the fittings.
The routing for the upper hose is shown above. Next to the AC line and behind the lower radiator coolant hose into the oil cooler adaptor ring. The line will not touch either of the other hoses when properly installed. The lower lines goes straight back and bends to meet the oil cooler adapter This line also will not touch any other parts of the Defender when correctly installed; therefore, no rubbing and no chance of damage to the new lines or other systems in the Defender.
Once everything is where you like it tighten all the fittings securely and start the engine for a short time and check for leaks. Once you confirm there are no leaks shut down the engine and re-install the clutch fan and radiator shroud and then top up your engine oil as needed, as some will have been lost when you remove the lines.
Here you can see the correct routing of the oil cooler lines from the bottom. As you can see they do not rub on anything and are far away from the heat of the exhaust manifold and they are made from top quality fittings that will not fail on the street or on the trail.