Oil pumps on Series Land Rovers are purely mechanical, being shaft driven by a skew gear on the camshaft. They are easy to remove (assuming you already have the sump off!), and easy to disassemble and have a look at.
The workshop manual gives the acceptable limits for the end float, backlash, and radial clearance of the gears inside the pump, so all you need is a set of feeler gauges and half an hour to take the thing apart and check the sieve and relief valve (a simple spring-based setup) while you're at it.
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| Mine is a 'later' type pump; one aluminium gear (idler), one steel (driver) |
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| Checking the end float on the idler gear |
My end floats were 0.12 and 0.15mm for the steel and ally gears respectively, radial clearance was tiny, up to about 0.1mm, and backlash was within the acceptable range. (I could get the backlash up to 0.3mm between some teeth, but only if I pushed the drive gear with my finger - unrealistic, if not impossible, with the drive shaft inserted.) So the gearing looked absolutely fine, and no muck or debris appeared to have made it past the sieve. The spring and ball in the pressure relief valve also looked fine, the sieve was clean and unclogged, and the sealing ring between it and the pump housing was still intact.
Overall, I'd say it was not a very old pump - and now I've had one apart I can see there's really not much that can go wrong with them.
I fit it back on the engine this evening, and it's good to know it's in a solid state before I replace the sump and fill her up with nice new oil.
If you've got your sump off and have an hour to spare and don't know the exact condition of your oil pump I would recommend giving it a bit of an inspection as it's easy to do and could potentially save a lot of diagnosis and wasted time at a later date.
