It’s only taken 3 days of work, in between bouts of crying and knuckle scraping, but all is well in Land Rover camp. And I have no idea why.
Here’s my step by step if anyone can shed any light on what the issue may have been, and previous post explaining symptoms. The short answer to that is: I have a Defender. It was overheating.
I started on Friday, first checking the oil and water for signs of head gasket failure. No dice. So I popped the valve cover to look a bit deeper for frosting on the valve heads, there was nothing there so I just replaced the gasket because it was quite happily leaking.
I then drained the oil to further check for water ingress and there was none, so that was the head gasket ticked off the list. With Oppo’s advice (h/t to Berang and countless others) I replaced the thermostat and bled the system, still it was still overheating. Then I popped the three coolant system caps, part drained the system and squeezed all the pipes, showing flow in all directions, so I assumed it wasn’t a blockage. I topped up and re-bled and still it showed as overheating.
Now it was onto the water pump, which was easy to unbolt but a pig to remove. As it turns out the military like to glue the water pump and gasket onto the engine, and just use the bolts for decoration. I only found this out when trying to remove the remains of the gasket which was a two hour job with a pack of Stanley blades. Joyous.
As it turns out the water pump was in good condition, with no corrosion or blades lost, and it spun easily in its housing.
Shitty gluey gasket off, new pump on (why waste it?), well shit, what next?
Aside from the gauge and sender unit for which I had no immediate parts available over the weekend to test, it was time to deconstruct the cooling system.
After bodging an external water pump so that I didn’t have to deal with 11 litres all at once, the rad and all hoses apart from those leading to the heater matrix came out, full system flush with a hosepipe on anything removable and a big syringe with a long tube shoved into the block. Everything flowed freely and there was no lumps or clogs or gunge anywhere, and the coolant that came out looked good. I put the radiator back in and flounced off home.
So this morning I was absolutely clueless, and all I had left was to rebuild her. That was done this afternoon with the help of Schaeftt, and after bleeding it very carefully over the last two hours or so (2 mins on 10 mins off) I sealed it all up and.... it’s fine now.
I shouldn’t complain, because it’s now ready for work tomorrow, but at the same time WHY did it show as overheating and take up 3 days of my life. Don’t get me wrong, I love working on my cars, but usually when I know what the problem is and get a firm resolution. This one got me by the short and curlies and just kept pulling, and I have no idea what I did right. Tell me.
Also: 2/10 would not want to attempt again