Mk2 Oil Pump
 

Can anybody say how much work is involved in changing the oil pump on a Mk2 ?

Quite a lot if the engine is in the car. Either the engine needs to be lifted, or the front suspension needs to come out to enable the oil pan to be removed. Once the oil pan is removed, then it's not too bad to do, some of the oil pickup pipes need to be removed for access and main bearing cap bolts removed and then properly torqued upon instillation.

Ok I'll ask the question. Why do you need to replace the oil pump?
Have you had a loss of oil pressure and who diagnosed oil pump failure?
cheers

Don't need to change it, nothing wrong with it.
Just wondered how much work involved if I wanted it changed over the winter to the upgraded item for more flow.
No other reason than curiosity.

I would leave well alone. We have found on this forum that old well run in pumps frequently do a better job than new ones. If you have lower than normal oil pressure worry about the state of bearings or BS from the pressure sender unit or gauge. Also check pressure relief valve. The pressure sender unit on top of the oil filter housing is notoriously unreliable.

+1
The most likely cause of low oil pressure on your gauge is the pressure transmitter. Them after that, as GMR says, the pressure relief valve. Of course if the engine bearings are totally worn out a new oil pump will do nothing.

The oil pump of an XK engine shouldn't need attention until the engine requires rebuilding due to general wear or other problems. An exception is if a cotter pin has fallen out of a big end and found its way into the pump - I don't know how, but they do. Again, the original GKN cotter pins don't usually drop out, but mechanics, who nowadays should use self-locking nuts, use cheap or old pins.

a1lry
Well, you certainly stirred up the forum!
I have never had an oil pump failure in a Jaguar and that is why I asked the question.
Actually, in my 60 + years of motoring in dozens of cars I have only ever had one oil pump failure in a1976 6-cylinder Ford.
As Glyn says leave well alone
Enjoy your car!

Well stirred up.
When I had the machining done on my engine during its rebuild I asked about replacing the oil pump. The engine had only done 75k miles. The old school machinist showed me my pump against a new pump someone had bought as a replacement. The tolerances on my old pump were smaller than on the new pump so it was not worth changing.
We have also had the discussion on the S Type forum about changing the oil pump in a 3.4/3.8 S Type to the oil pump from a 420 engine as someone suggested it was a good upgrade being a more powerful pump. Research showed that the oil pump part numbers were exactly the same so it was not an upgrade at all. Myth busted. So where are you getting an upgraded oil pump from and where is the proof that it is a better pump than the one you already have?
As it has been stated it is quite a bit of work to get to the pump unless you are doing a full engine rebuild so I would leave well alone and check the pressure relief valve and have your gauge calibrated.

As for cotter pins coming off. My oil pressure dropped to nothing several years ago so I pulled the oil filter housing from the side of the engine and found half the leg of a cotter pin stuck in the pressure relief valve stopping it from closing!

This by the way, the part sticking up on the left, is your oil pump in the sump. Taken when I stripped my engine down so the engine is upside down on an engine spit.

https://cimg7.ibsrv.net/gimg/www.jag...1bca8ad663.jpg

I reckon the oil pump will do 2 engine rebuilds with ease. Mine was perfect at 90K miles with tight tolerances. The only caveat may be people that don't change their oil & filter at approx every 6000 miles & especially if you are running on Synthetics where I would recommend changing at 10K miles. The truth of the matter, unless you are running high mileages, you are going to change Synthetics or whatever on time alone. i.e every 2 to 3 years. The only reason to change the pump is because it is exposed. As Cass says some of the new pumps are not so great.

Lubricants have come a hell of a long way since the XK engine was designed. Should you decide to be a little conservative that's OK too. But not to the old 3500 mile oil change days.

Also remember the massive advances in filtration from the Tecalemit days.

Low mile p/a modern cars that are called in once a year for oil changes are to make dealers rich and to examine other things.

When you drive your car get it up to full temperature & give it a good run to drive water out of your oil. In many short trips water level in oil can get up to 6 or 7%. I know because I ran a test program with our Automobile Association for a year to monitor that & friction modified oils.