Monday, June 27, 2011

A new Land Rover engine failure

Have you had an oil pump fail on a 2000-2004 Land Rover V8?  At Robison Service, we are seeing pump failure more and more.






Last week we encountered a 2003 Discovery with a failure I have not seen before.  The car came to us with an oil light on most of the time, and lifter noise when the light was on.  The noise vanished as soon as the light went out, confirming that the car has a problem with oil pressure, and not a problem with the oil light sender.

This engine is reasonably clean, and free of sludge.  This wasn't a neglect issue.

We removed the front cover, and found the oil pump fractured.  I have seen several similar failures in the past year, but most of the time, when we get them, the engine has already blown.  This one had not.  The outer gear of the pump had fractured into four pieces.  I don't know how much longer it would have worked before failing entirely but it was clearly close to the end.



















I thought we should pull the oil pan to check the bearings, and to my surprise we saw this laying in the pan.  As you can see, the pan is otherwise pretty clean.  The spots in the image are just bits of crud you see in any oil pan.  There is no metal or evidence of damage visible.  The oil is normal looking.





































The crescent piece you see is the thrust face from the center main bearing cap.  With no washer in place the crank moves back and forth a few mm.  I think this is the original failure . . . I think the center bearing broke for some reason, the crank moved back and forth over a period of time, and that led to the eventual cracking of the oil pump gear.

Had we not caught this, the engine would have failed in the fairly near future. We will repair the bearing and time will tell how that holds up.  I have some concerns because the crankshaft face may be galled. and that would ruin a new thrust face in short order.  If we find that we face the choice of filing it in place, or removing the engine and essentially getting into an overhaul situation.

Now that I know this I realize we can check for the problem on an assembled motor by moving the crank pulley back and forth to check for excess play.  I wonder how many more of these are out there, waiting to fail?

8 comments:

OkieRover said...

Thank heavens the 4.2 in my classic NEVER has any troubles like this. wink wink nudge nudge.

Great article. Thanks.

johnny said...

lucky!11!!

good to see it is repaird before died!

turbodave said...

Take a look at the dowels on the front of the block - the countersinks behind the dowels are very likely machined off-centre to the dowels. Also, all the (front cover) bolts will likely be biased to one side of the holes. This is because many 2003 models had badly machined pump dowels, which break the oil pump gears - sometimes losing oil pressure, other times continuing to work just fine.

dan patterson said...

Just encountered the exact same problem on a 2003 4.6. Were you able to roll the bearing out by just removing the cap or did you end up pulling the engine? Did the repair hold up or did the damaged crank eat the new bearing?

John Elder Robison said...

We didn't try to swap the bearing because that would have left us responsible for a subsequent failure. The crank was grooved too deeply

Bert Arias said...

I had a oil pump failure. My engine stopped running. I took my front cover off and The pump gears are broken. What else should I look for?

John Elder Robison said...

Bert, you would be wise to check for damage to the main bearings. As for the gears . . . the pump is part of the front cover and serviced as a unit

Oscar Barberena said...

I have an 03 disco I'm the original owner Mobil one oil changed every 5k 90k miles on motor.
we live in southern California and are having the heads redone due to a coolant leak but no over heating issues. my question is should I have the tech tear into the oil pump? if the pump is fine should I just have them put it back together or buy a new pump regardless?. Thank you. I wish you guys had a shop in the west coast!!