Cooling System and Aircon

I have been putting up with the common 300Tdi ancilliary squeal for some time now.  The belt and tensioner have been previously replaced, with some limited benefit, but the squeal still persisted. The fact that this squeal was only present when the engine was cold pointed towards the water pump bearings and seal, so I have just replaced the pump with a new unit (genuine) from Dunsfold Land Rover.

Removing the water pump and PAS pump pulleys to get to the water pump casing bolts was a pig, but they eventually came out.  The water pump bolts were all tight but came free, except one, which fractured the 10mm hex socket, resulting in a rounded bolt head.  Thankfully, a good friend has a set of Irving bolt extractors, made for exactly this sort of thing.  Five minutes later, the bolt was out.

After cleaning up the mating faces, the new pump was fitted with a new gasket and smear of sealant on the faces.  The bolts were given a generous smear of copper grease along their entire length to prevent future trouble, and the pulleys were given a thorough cleaning and degreasing before refitting, again with copper grease applied to their bolts.  The steel heater matrix feed pipe along the top of the head was weeping from the aft end joint, so it was removed and cleaned up before refitting with new Jubilee clips.

The radiator, which is the original unit, had not only lost a large amount of its fins, but had started weeping from the core.  It wasn’t losing much coolant, but the antifreeze stain was pretty large.  Since the system was going to need topping up with new antifreeze from the water pump work, it made sense to replace the radiator too, so that has been done.  The intercooler was also removed for cleaning, but inspection has revealed not only a fair amount of corroded fins twisted and blocking the air path, but also a large dent on one of the air tubes (stone damage).  These things are to be expected after 15 years and 172,000 miles – the rad and intercooler have done pretty well to last that long and were still doing their job without apparent loss of performance, but refitting worn out components is plain daft, so it will be replaced.   That same good friend is coming to the rescue again with the intercooler he removed from his Defender when he upgraded to a full width Allisport intercooler.

Now, since I have already assembled almost the entire aircon system for retrofit, and the condensor sits in front of the radiator/intercooler, now is an opportune time to fit that unit.  The condensor is a second hand but new unit, while the fans are used but cleaned up and tested.  The drier unit (a bottle on the front of the condensor, between the fans) is new – left open to atmosphere for more than a very short period while fitting renders them scrap as the atmospheric moisture is absorbed, so the old drier was useless.  I’ll not be fitting the rest of the system just yet, but need to fit the drier to the condensor, so the condensor pipes will simply be capped where they emerge alongside the oil cooler side of the rad for the time being.

I still need to get the two sensors for the thermostat housing elbow – aircon equipped models have two sensors in that elbow, the lower value one which activates the electric fans on the condensor if the engine’s main fan is not managing to keep the engine temperature down, and the higher value sensor which shuts down the aircon if the engine temperature still continues to rise above acceptable levels.  I’d prefer to find a complete elbow as that would save having to drill and tap mine for the sensors, but the casting is the same, so I can do it the hard way if needed.  I’m also missing one aluminium pipe which extends from the (capped) union of the condensor to a joint on the inner wing, where it connects to another similar pipe that runs to the evaporator inside the cabin.  The good news is that the radiator company I used for the rad recore and drier unit can make up such pipes very cheaply, so it shouldn’t be a problem if I can’t find a genuine second hand one (they cost over £80 new!).