Bought a Sludge lemon. Is it fixable? BG flush?

[iverson03tj]

Yes as others have said. Replace oil pressure sensor. Try a mechanical gauge of known quality.

Replace oil filter in case yours is defective and it's cheap.

I would not go crazy with flush and solvents. Whats in the oil pan needs to be mostly a lubricant, not a solvent. Forget MMO.

I already changed the sensor and chekced the oil pressure with a guage, oil pressure it up to spec until the engine is off. oil pan didnt have much metals, with the exception of 1 plastic timing chain guide.

 

[iverson03tj]

I am not a fan of Non-Oil solvents. Why not simply use a slightly higher viscosity oil that is known to clean? Solves the pressure problem and slowly cleans. 100,000Km later, the engine will be just fine.

Without the risk of dissolving gaskets with a strong solvent, or diluting your oil with a non-oil.

M1, HM 10W-40 will clean, as an example.

isn't running 10w 40 on an engine spec's for 0w30 to 5w-40 risky? Keep in mind I'm in canada, where we get -20c weather. most of the engine wear happens at start up under operating temps.

 

[edyvw]

isn't running 10w 40 on an engine spec's for 0w30 to 5w-40 risky? Keep in mind I'm in canada, where we get -20c weather. most of the engine wear happens at start up under operating temps.

No it is not. In N55 you can run pretty much anything. There is no such thing as too thick. I have seen people running 10W60 in N55 on track with normal internals. Also, Europen oil recommendations are based on HTHS, not grade. LL01 (required for N55) has minimum HTHS of 3.5cP. So for example, 0W30 Castrol Edge has HTHS around 3.58cP. Motul 0W40 X-MAX has HTHS of 3.6cP. N55 also can run FE (Fuel Efficiency) LL01FE oils, with a minimum HTHS of 3cP. Actually, considering rod bearing issues until 2014, 5W40 with high HTHS is preferred.
Sorry about the vehicle loss. That engine was definitely neglected, possibly using "synthetic" oil, off-the-shelf ILSAC GF6 oil. N55 runs super hot. The easier you drive it, the hotter it gets. The harder you drive it, the cooler is trying to get. That is how the cooling system is designed.
Are you sure the pieces in the oil sump were from the timing chain guide and not the belt? N generation of BMW engines (N20/26/51/52/53/54/55) are notorious for "eating" serpentine belts through the front crank seal if the belt was not replaced on time or if OFHG leaks over the belt. Then, you have to fish out all the pieces from the sump if the engine survives.
N55 has a variable oil pump. Because of that, very often on earlier models (until 2014) rod bearings would die when OFHG is changed and then the vehicle started without priming oil pump (disconnecting fuel injectors and firing up three times in 10sec intervals. That is when the pump is in high-pressure mode). So, my guess is that you oil pressure is bcs. oil pump was in low-pressure mode.

 

[iverson03tj]

No it is not. In N55 you can run pretty much anything. There is no such thing as too thick. I have seen people running 10W60 in N55 on track with normal internals. Also, Europen oil recommendations are based on HTHS, not grade. LL01 (required for N55) has minimum HTHS of 3.5cP. So for example, 0W30 Castrol Edge has HTHS around 3.58cP. Motul 0W40 X-MAX has HTHS of 3.6cP. N55 also can run FE (Fuel Efficiency) LL01FE oils, with a minimum HTHS of 3cP. Actually, considering rod bearing issues until 2014, 5W40 with high HTHS is preferred.
Sorry about the vehicle loss. That engine was definitely neglected, possibly using "synthetic" oil, off-the-shelf ILSAC GF6 oil. N55 runs super hot. The easier you drive it, the hotter it gets. The harder you drive it, the cooler is trying to get. That is how the cooling system is designed.
Are you sure the pieces in the oil sump were from the timing chain guide and not the belt? N generation of BMW engines (N20/26/51/52/53/54/55) are notorious for "eating" serpentine belts through the front crank seal if the belt was not replaced on time or if OFHG leaks over the belt. Then, you have to fish out all the pieces from the sump if the engine survives.
N55 has a variable oil pump. Because of that, very often on earlier models (until 2014) rod bearings would die when OFHG is changed and then the vehicle started without priming oil pump (disconnecting fuel injectors and firing up three times in 10sec intervals. That is when the pump is in high-pressure mode). So, my guess is that you oil pressure is bcs. oil pump was in low-pressure mode.

Thanks for sharing it HTHS tip! I will keep that in mind this time around. After owning7 BMW's Bought a Q5 this time. Let's see if the grass is greener

Yes the the pieces in the oil sump were from the timing chain guide, no sign of belt material. It was a concern of mine so I did change the belt and tensioner and OFHG last year to prevent that from happening. PO did state he changed the timing belt and after inspection it does look new.

I always primed my engine by removing the ignition connector on the DME. It's way faster than removing the injector wires seperately from the injector, as MY2012 has the air filter going over the valve cover. I don't think that the Previous owner did do that.

I did keep my old rod bearings, will share come pictures of how they looked when I get a chance.

 

[Craig in Canada]

No it is not. In N55 you can run pretty much anything. There is no such thing as too thick.

I must state first: I'm not arguing with you, just putting forth some info that's 'out there' for N55. My N55 is a MY 2011, so I've been paying attention to Internet lore on "doomed" rod bearings. Unfortunately it's an X-Drive, so anything involving the oil pan is a royal PITA, prompting me to just leave it buttoned up.

I've heard (from live people) and read (online) that lubrication issues in cyl 6 is one of the common issues, and multiple folks have stated that it's due to clearances being too tight for heavier oils like 5W40+ which "enthusiasts" put in thinking it's a good thing for any BMW but in fact does more harm than running the FE oils speced by BMW. Also, pushing it too hard when cold leads to any grade of oil which is thick on cold start being unable to get where it needs in cyl 6. One engine builder said he rebuilds with larger tolerances and thereafter suggests "traditional" 5W40 for the rest of the vehicle's service life, just like in the 'good old days' when the factory designed them for this grade.

As with many things that one hears "around", it rings true with a certain amount of common sense. One of the live human sources I heard this from went on to say that a contributing cause was that GTL oils like Pennzoil Platinum were too "dry" and accelerated the issues. Sounds like the discussions here 15-20 years ago concerning low sulphur fuels. At any rate, I have to wonder if I need to ignore everything they said based on their "dry GTL" comment LOL.

In the end, every time I pick up a jug of my LL-01 PP Euro 5W40, I wonder about how my rod bearings are doing and think about making the switch to a 5W30 or 0W30 LL-04 or LL-01FE (LL-04s are easy for me to get more affordably here) just in case some of these people are right... N55 rod bearings are G-488 and G-444 (from my research) so from my understanding Blackstone isn't going to find any smoking guns to point at rod bearings.

 

[Glenda W.]

I must state first: I'm not arguing with you, just putting forth some info that's 'out there' for N55. My N55 is a MY 2011, so I've been paying attention to Internet lore on "doomed" rod bearings. Unfortunately it's an X-Drive, so anything involving the oil pan is a royal PITA, prompting me to just leave it buttoned up.

I've heard (from live people) and read (online) that lubrication issues in cyl 6 is one of the common issues, and multiple folks have stated that it's due to clearances being too tight for heavier oils like 5W40+ which "enthusiasts" put in thinking it's a good thing for any BMW but in fact does more harm than running the FE oils speced by BMW. Also, pushing it too hard when cold leads to any grade of oil which is thick on cold start being unable to get where it needs in cyl 6. One engine builder said he rebuilds with larger tolerances and thereafter suggests "traditional" 5W40 for the rest of the vehicle's service life, just like in the 'good old days' when the factory designed them for this grade.

As with many things that one hears "around", it rings true with a certain amount of common sense. One of the live human sources I heard this from went on to say that a contributing cause was that GTL oils like Pennzoil Platinum were too "dry" and accelerated the issues. Sounds like the discussions here 15-20 years ago concerning low sulphur fuels. At any rate, I have to wonder if I need to ignore everything they said based on their "dry GTL" comment LOL.

In the end, every time I pick up a jug of my LL-01 PP Euro 5W40, I wonder about how my rod bearings are doing and think about making the switch to a 5W30 or 0W30 LL-04 or LL-01FE (LL-04s are easy for me to get more affordably here) just in case some of these people are right... N55 rod bearings are G-488 and G-444 (from my research) so from my understanding Blackstone isn't going to find any smoking guns to point at rod bearings.

Nothing against you but that’s an awful lot of oil misconceptions which range from “clearances to tight” to “dry”oil.

 

[Craig in Canada]

Nothing against you but that’s an awful lot of oil misconceptions which range from “clearances to tight” to “dry”oil.

Oh yes! - I loved the "dry oil" story. My mind occasionally churns on the sum total of everything I've heard, some of which is known to be baloney. Considering "As thick as possible, as thin as necessary" I find myself considering going on the thinner end of what still meets the LL-* criteria that's deemed acceptable for the N55, that's all I'm really saying. Especially in my climate. Maybe "necessary" is a little thinner on the N55, maybe it's not.

Something's going on with N55s, particularly earlier ones. Failure stories are all over the map, not predictable like S85 and S65. They're not all OFHG priming related either. Because it's an X-Drive, doing rod bearings just because the Internet says so might be half the value of the vehicle in my market at this point. But, I'll be thinking seriously about it whenever my oil pan gasket starts to leak

 

[edyvw]

I must state first: I'm not arguing with you, just putting forth some info that's 'out there' for N55. My N55 is a MY 2011, so I've been paying attention to Internet lore on "doomed" rod bearings. Unfortunately it's an X-Drive, so anything involving the oil pan is a royal PITA, prompting me to just leave it buttoned up.

I've heard (from live people) and read (online) that lubrication issues in cyl 6 is one of the common issues, and multiple folks have stated that it's due to clearances being too tight for heavier oils like 5W40+ which "enthusiasts" put in thinking it's a good thing for any BMW but in fact does more harm than running the FE oils speced by BMW. Also, pushing it too hard when cold leads to any grade of oil which is thick on cold start being unable to get where it needs in cyl 6. One engine builder said he rebuilds with larger tolerances and thereafter suggests "traditional" 5W40 for the rest of the vehicle's service life, just like in the 'good old days' when the factory designed them for this grade.

As with many things that one hears "around", it rings true with a certain amount of common sense. One of the live human sources I heard this from went on to say that a contributing cause was that GTL oils like Pennzoil Platinum were too "dry" and accelerated the issues. Sounds like the discussions here 15-20 years ago concerning low sulphur fuels. At any rate, I have to wonder if I need to ignore everything they said based on their "dry GTL" comment LOL.

In the end, every time I pick up a jug of my LL-01 PP Euro 5W40, I wonder about how my rod bearings are doing and think about making the switch to a 5W30 or 0W30 LL-04 or LL-01FE (LL-04s are easy for me to get more affordably here) just in case some of these people are right... N55 rod bearings are G-488 and G-444 (from my research) so from my understanding Blackstone isn't going to find any smoking guns to point at rod bearings.

I just can’t believe what I have read. Nothing against you, I know you are just messenger.

 

[edyvw]

Oh yes! - I loved the "dry oil" story. My mind occasionally churns on the sum total of everything I've heard, some of which is known to be baloney. Considering "As thick as possible, as thin as necessary" I find myself considering going on the thinner end of what still meets the LL-* criteria that's deemed acceptable for the N55, that's all I'm really saying. Especially in my climate. Maybe "necessary" is a little thinner on the N55, maybe it's not.

Something's going on with N55s, particularly earlier ones. Failure stories are all over the map, not predictable like S85 and S65. They're not all OFHG priming related either. Because it's an X-Drive, doing rod bearings just because the Internet says so might be half the value of the vehicle in my market at this point. But, I'll be thinking seriously about it whenever my oil pan gasket starts to leak

The rod bearings are just finicky. Over time (bad oil, long OXI, not priming) leads to failure. After 2014 they are fine.