HELP PlEASE
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4wd Low
Joined: Dec 2025
Posts: 12
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HELP PlEASE
2003 Land Rover discovery. Bought 8 weeks ago run great for that amount of time. Has oil leak on front of engine I figured was oil pump related. Also noticed a small coolant leak by thermostat housing. The other night the heater quit close to home. Got it home added what seemed like less than a quart. Got up drove to work no problem it was cold, way home starting knocking and check engine light flashing. Cylinder 3 5 7, changed plugs wires coil put back together runs perfectly for 15 minutes till warm and starts knocking. Cut exhaust infront of cat thinking it was clogged started up and first time I’ve noticed oil light flashing. Sounds like a new engine to me unless you guys have a better idea? Where to get a new engine also would be appreciated. Thanks
Mudding
Joined: Feb 2012
Posts: 138
Likes: 62
From: Da Windycity
Do you have a code reader? What codes have you pulled? Are you running the OEM style thermostat? If so I would replace it or look into an inline setup with a 180 t-stat. I would also run a bluetooth OBD setup to check engine temp, O2 sensors, etc......cheap and effective. Lastly I would look into checking oil pressure. A sandwich oil filter attachment/gauge from Glowshift will work.
TReK
Joined: Oct 2007
Posts: 2,767
Likes: 1,979
From: Pacific NW
Sorry for the troubles. Couple questions and comments based on this post.
First -- it’s never a clogged exhaust unless the thing has been severely misfiring for a very long time. I don’t understand why people think D2s have clogged exhausts all the time but mechanics even seem to say this (bad ones). . So I’d remove that from your thinking. You are going to have to fix the exhaust you cut now.
Oil light flashing to confirm this --> Oil light is on when you turn the key to ON, then goes off after a second when starting as usual, then after it warms up, it starts flashing?
is that right?
I think it’s a big jump to a new engine. Did it ever overheat? If so, you might be cooked... these motors do not do well after significant overheat situations.
How severe is oil leak and what is oil level?
You could have a bad oil pump (which is different from “needing a new engine).
How many miles are on this thing?
First -- it’s never a clogged exhaust unless the thing has been severely misfiring for a very long time. I don’t understand why people think D2s have clogged exhausts all the time but mechanics even seem to say this (bad ones). . So I’d remove that from your thinking. You are going to have to fix the exhaust you cut now.
Oil light flashing to confirm this --> Oil light is on when you turn the key to ON, then goes off after a second when starting as usual, then after it warms up, it starts flashing?
is that right?
I think it’s a big jump to a new engine. Did it ever overheat? If so, you might be cooked... these motors do not do well after significant overheat situations.
How severe is oil leak and what is oil level?
You could have a bad oil pump (which is different from “needing a new engine).
How many miles are on this thing?
Thread Starter
|
4wd Low
Joined: Dec 2025
Posts: 12
Likes: 0
Sorry for the troubles. Couple questions and comments based on this post.
First -- it’s never a clogged exhaust unless the thing has been severely misfiring for a very long time. I don’t understand why people think D2s have clogged exhausts all the time but mechanics even seem to say this (bad ones). . So I’d remove that from your thinking. You are going to have to fix the exhaust you cut now.
Oil light flashing to confirm this --> Oil light is on when you turn the key to ON, then goes off after a second when starting as usual, then after it warms up, it starts flashing?
is that right?
I think it’s a big jump to a new engine. Did it ever overheat? If so, you might be cooked... these motors do not do well after significant overheat situations.
How severe is oil leak and what is oil level?
You could have a bad oil pump (which is different from “needing a new engine).
How many miles are on this thing?
First -- it’s never a clogged exhaust unless the thing has been severely misfiring for a very long time. I don’t understand why people think D2s have clogged exhausts all the time but mechanics even seem to say this (bad ones). . So I’d remove that from your thinking. You are going to have to fix the exhaust you cut now.
Oil light flashing to confirm this --> Oil light is on when you turn the key to ON, then goes off after a second when starting as usual, then after it warms up, it starts flashing?
is that right?
I think it’s a big jump to a new engine. Did it ever overheat? If so, you might be cooked... these motors do not do well after significant overheat situations.
How severe is oil leak and what is oil level?
You could have a bad oil pump (which is different from “needing a new engine).
How many miles are on this thing?
Last edited by cwjdrake11@gmail.com; Dec 14, 2025 at 02:30 PM.
The temp gauge is little more than an idiot light, it moves to the low part at 140, the middle at 150, then stays there till it reaches 230 at which point it goes to the top of the range, at 250 it pins the gauge and turns the red light on. To drive these with any sense of reliability you need some sort of alternative temperature gauge, many use an obd2 port gauge like the ultragauge, others install aftermarket temperature gauge.
A small percentage (less than 10%) of the trucks do experience cracked oil pump gears that cause low oil pressure. The ECU does not throw a code for low oil pressure, the only indication you get is the red oil pressure warning light. Many of us also run an external oil pressure gauge. Given your oil light is flashing, you need to install an external gauge and check the pressure. If the gears are cracked (most likely cause, the other common cause is a walked cam bearing - caused by an overheat event), they can be replaced by removing the oil pan and front cover. if the pan comes off you need to check for walked cam bearingsa and worn rod bearings. Also, make sure it has enough oil in and always use 15w40, I have excellent success with diesel oil (three trucks over 220k miles on original engines).
If you changed coils, wires, and plugs and you are still getting misfires your most likely cause is you mixed up the plug wiring. The knocking is likely caused by that incorrect ignition timing. Double and triple check that.
These engines can be extremely durable as long as you don't overheat them (inline thermostat) or run them with low oil pressure. Go back and read every single sticky at the top of this forum. Get a temperature gauge, check the oil pressure, come back and let us know.
Then go back and read every sticky at the top of this forum. Twice.
A small percentage (less than 10%) of the trucks do experience cracked oil pump gears that cause low oil pressure. The ECU does not throw a code for low oil pressure, the only indication you get is the red oil pressure warning light. Many of us also run an external oil pressure gauge. Given your oil light is flashing, you need to install an external gauge and check the pressure. If the gears are cracked (most likely cause, the other common cause is a walked cam bearing - caused by an overheat event), they can be replaced by removing the oil pan and front cover. if the pan comes off you need to check for walked cam bearingsa and worn rod bearings. Also, make sure it has enough oil in and always use 15w40, I have excellent success with diesel oil (three trucks over 220k miles on original engines).
If you changed coils, wires, and plugs and you are still getting misfires your most likely cause is you mixed up the plug wiring. The knocking is likely caused by that incorrect ignition timing. Double and triple check that.
These engines can be extremely durable as long as you don't overheat them (inline thermostat) or run them with low oil pressure. Go back and read every single sticky at the top of this forum. Get a temperature gauge, check the oil pressure, come back and let us know.
Then go back and read every sticky at the top of this forum. Twice.
Last edited by Extinct; Dec 14, 2025 at 05:52 PM.
Thread Starter
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4wd Low
Joined: Dec 2025
Posts: 12
Likes: 0
The temp gauge is little more than an idiot light, it moves to the low part at 140, the middle at 150, then stays there till it reaches 230 at which point it goes to the top of the range, at 250 it pins the gauge and turns the red light on. To drive these with any sense of reliability you need some sort of alternative temperature gauge, many use an obd2 port gauge like the ultragauge, others install aftermarket temperature gauge.
A small percentage (less than 10%) of the trucks do experience cracked oil pump gears that cause low oil pressure. The ECU does not throw a code for low oil pressure, the only indication you get is the red oil pressure warning light. Many of us also run an external oil pressure gauge. Given your oil light is flashing, you need to install an external gauge and check the pressure. If the gears are cracked (most likely cause, the other common cause is a walked cam bearing - caused by an overheat event), they can be replaced by removing the oil pan and front cover. if the pan comes off you need to check for walked cam bearingsa and worn rod bearings. Also, make sure it has enough oil in and always use 15w40, I have excellent success with diesel oil (three trucks over 220k miles on original engines).
If you changed coils, wires, and plugs and you are still getting misfires your most likely cause is you mixed up the plug wiring. The knocking is likely caused by that incorrect ignition timing. Double and triple check that.
These engines can be extremely durable as long as you don't overheat them (inline thermostat) or run them with low oil pressure. Go back and read every single sticky at the top of this forum. Get a temperature gauge, check the oil pressure, come back and let us know.
Then go back and read every sticky at the top of this forum. Twice.
A small percentage (less than 10%) of the trucks do experience cracked oil pump gears that cause low oil pressure. The ECU does not throw a code for low oil pressure, the only indication you get is the red oil pressure warning light. Many of us also run an external oil pressure gauge. Given your oil light is flashing, you need to install an external gauge and check the pressure. If the gears are cracked (most likely cause, the other common cause is a walked cam bearing - caused by an overheat event), they can be replaced by removing the oil pan and front cover. if the pan comes off you need to check for walked cam bearingsa and worn rod bearings. Also, make sure it has enough oil in and always use 15w40, I have excellent success with diesel oil (three trucks over 220k miles on original engines).
If you changed coils, wires, and plugs and you are still getting misfires your most likely cause is you mixed up the plug wiring. The knocking is likely caused by that incorrect ignition timing. Double and triple check that.
These engines can be extremely durable as long as you don't overheat them (inline thermostat) or run them with low oil pressure. Go back and read every single sticky at the top of this forum. Get a temperature gauge, check the oil pressure, come back and let us know.
Then go back and read every sticky at the top of this forum. Twice.
Well the p1590 is your Three Amigos, I don't have the other three codes memorized but they are not misfire codes. The misfire code for 5 and 7 is po305 and po307. 12 PSI won't turn on the oil pressure light, I don't remember the exact pressure but it's somewhere below 7. 12 is pretty low at startup though so you definitely have an oil pressure problem. Now the task is to find out why there is low oil pressure. You can start with removing the oil pan and looking up to see if the cam bearings have walked out of their positions, try to take some pictures and post them here and I will have a look and let you know if they're walked. I actually had one truck where I found the cam bearing in the oil pan when I took the oil pan off. If it's not obvious that you have walked cam bearings The Next Step would be to remove the front cover and check for a cracked oil pump. I would also remove one rod cap to check the bearing wear there.
Thread Starter
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4wd Low
Joined: Dec 2025
Posts: 12
Likes: 0
Well the p1590 is your Three Amigos, I don't have the other three codes memorized but they are not misfire codes. The misfire code for 5 and 7 is po305 and po307. 12 PSI won't turn on the oil pressure light, I don't remember the exact pressure but it's somewhere below 7. 12 is pretty low at startup though so you definitely have an oil pressure problem. Now the task is to find out why there is low oil pressure. You can start with removing the oil pan and looking up to see if the cam bearings have walked out of their positions, try to take some pictures and post them here and I will have a look and let you know if they're walked. I actually had one truck where I found the cam bearing in the oil pan when I took the oil pan off. If it's not obvious that you have walked cam bearings The Next Step would be to remove the front cover and check for a cracked oil pump. I would also remove one rod cap to check the bearing wear there.
Misfires are almost always ignition related. Given they are adjacent cylinders you might want to do a compression check on those cylinders, it's possible you blew the head gasket between those two cylinders and there is no compression in them
