Hello All - I need help before I go deep into dismantling. 2000 LR Disc II with 222K miles.

My engine oil light kept coming on, so I stopped driving the vehicle. Bought a 12 x 1.5 to 1/4" - 27 bushing reducer so I could check my oil pressure. In the meantime, I purchased the Tee fitting to fit the oil pressure sensor and add in a gauge. So I checked my pressure today.

• 45psi at start
• 30psi after 10 minutes
• 45 psi at 1800 rpm
• once warm ~20 minutes running, it dropped to 20psi
• Then, every ~18 to 20 seconds on the dot, it would quickly drop to 10psi and swing back up to 20psi
• This was consistent for 6 cycles...20psi, down to a quick 10psi and back up to 20 psi

Does the oil system cycle? Why would it drop and sustain pressure in such a consistent pattern?

I have a very minor front seal leak on the crankshaft pully. I'm talking 1 drop every 3 minutes. It drips down to the oil pan body and eventually drips onto the ground. I have the replacement seal ready.

My thoughts are:

• The front seal leak is causing the pressure drop
• The pick-up tube in the oil pan is clocked and causes a lag in pressure
• The oil pump gears are worn or...dare I say it, broken in three parts, as I've so commonly read about on these forums

While I don't mind dropping the pan, pulling the front cover and getting down to the timing chain, oil pump gears, seals, etc...
I don't want to - if I don't need to.

All thoughts and suggestions welcomed. Note - I will be doing all the work and I'm as much a mechanic as I am a cook. Sometimes I overcook the meat.

July 2011: last time I changed out timing chain, water pump and speedy sleeved the crankshaft pully.
October 2017: Resurface mill, hot tank and pressure test heads

Thank you all in advance for your replied.
Diego

 

That is a very strange characteristic. Does it only do that at idle, or does it also do it at speed? Does it do it cold? Or only hot? Sitting in the driveway with it idling, what RPM does it go away?

 

Cold resting at a solid 45psi, slowly down to 30psi and once warm went down to 20psi. At idle, it would do the quick drop to 10psi and climb back up. I kept 1800 rev for 45seconds and it remained at 45psi.

I can't run anymore tests, as the front cover is off. Nothing is broken. The oil pump gears are good, the timing chain looks just at it did when I last changed it at 100K miles (no excessive wear or lose chain), and the oil pressure bypass valve (spring) is not stuck. I did notice there were a few oil pan bolts "not as tight" as I would have hoped, when I took it off. The oil pan gasket did not come out in one piece. There was a corner section that appears to be cracked and weathered. Maybe that was it, or the crankshaft seal leak. As I was turning the crankshaft pully in position to undo the bolts (turning the engine by hand), oil was dripping from the front seal.

I've chosen to replace all components while I'm in there:

• Timing chain and gears <--as long as I don't turn the engine, I should NOT have to worry about messing with the engine timing right?? I've done the chain, but this will be the first time removing the gears.
• Oil pump gears
• Oil pressure bypass valve spring (I can't find it on the Atlantic British website but I have an email out to them)
• Front crankshaft seal
• Oil separator/breather
• Fan assembly with viscous coupling
• Drive belt tensioner & idle pully
• Polyvee serpentine belt
• Bosch spark plugs & ignition wires (with new wire spacer clips)
• ...and I'm also putting on the rear ladder to access by rack <--I'm being optimistic that all these new fixes will make it run another 100K miles

 

PCV separator clogged ?