Uh oh, it's not the timing chain guides

[tekoo]

With all due respect:
1-BMW recommends using the 5W for all engines during the first 2000 km including engines that normally require higher viscosity oil (e.g 5W-30 during first 2k kms before switching to 10W in M series). So it seems what BMW recommendations do not match your statement/analysis.
2-No where in my discussion have I limited my conversation to Castrol brand specifically. These statements apply to all automotive oil in general.
3-There is no extra advantage to 0W over 5W except when temperature drops below -20 Celsius (there is a reason why BMW specifically linked 0W to -20 Celsius conditions only as I stated before) . Please see all attached charts and feel free to search for more.
DCB110C5-C327-4270-89A1-C9C414331A7D.jpeg2D6CD7C9-0EFA-405A-BB1C-C460BF8DCDA8.jpeg3E73A450-68AD-4CD4-93BA-37688A5D6E5D.jpeg847128B5-3F5A-402F-BFD7-47CC22D6D6DF.jpeg

[tekoo]

1- 0W has no extra advantage over 5w except at or below -20 Celsius. There is a reason BMW linked 0w to the -20 Celsius. Please see charts below from non-BMW sources that confirm the same fact.
18171A8B-D424-419F-A93B-8A350E835D98.jpeg31728965-B210-4AC1-9590-816D993976DB.jpeg359D6003-78CD-4126-A58C-DA87A317FC05.jpeg68D3BD2A-2C1A-4BC4-AFDB-2A377CEC9356.jpeg
2- I did not referr to Castrol oil specifically at any point. My statements are directed towards all automotive oil in general.
3- BMW recommends 5W-30 during the initial 2000 Kms for all new BMW engines including the engines that normally run on higher viscosity oil (e.g. M class engines switch from 5w-30 to 10w after first 2000 kms).
4-BMW ‘break in oil’ can be 5w-30 with added polymers that provide ‘extra protection’. Viscosity is only one out of many factors and additives in synthetic oils. These extra protection polymers are probably not present in average 5w-30 at Walmart.
5-Who mentioned anything about engine oil after warm up?!
6-Also please note that extreme weather oil 0W probably has unique expensive cold weather specific polymers and additives that prevent degradation, freezing and who knows what at such cold temps. It’s not only a matter of oil thickness and viscosity. Utilizing these additives in normal day to day driving in the state of FL for example would be similar to filling coolant with antifreeze before driving to the beach!!
7-Again ‘long life’ is not synonymous with viscosity. Long life is more like an ‘iso’ classification that determines the overall quality of the oil and how beneficial to longevity of the engine. Among long life certified products you will have to pick 0W at or below -20 Celsius to compensate for the increased oil viscosity at extremely low temperatures as well as benefit from any additional additives that may lower the freezing point of oil and allow the engine a more easy run. These properties/additives are the only UNIQE properties that could make 0W long life certified oils stand out from other (non-0W) long life certified oils. Otherwise it would not be a cost effective choice.

[TheAngryBear]

Great oil debate but it’s been 15 posts and OP still has an issue.

OP, thought you had checked oil chain and pump during the guides, correct?


2001 750iL DD74441
Stock

RIP: 2003 540iA Sport GS56111
H&R front springs, Ultimate Cup Holder, Euro Dash & Armrest, Grom, BavSound Stage1

[R Shaffner]

+1 on the idea of checking the electrical system for the pressure switch, especially for an intermittent problem. (Badly worn bearings or a weak pump would be more likely to cause consistent problems, not intermittent ones. Same with an oil viscosity issue.)

Something else to consider... Could there be a problem with the oil pressure relief valve? It's part of the oil filter assembly. I suspect it opens at a certain pressure level, at higher rpm. If it stuck open intermittently, then the pressure would be too low when the rpm dropped. (You said the warning light goes away as soon as you increase the rpm, right?)

Since I'm a shade-tree mechanic, I always look for easy/cheap ways to test things. Using a pressure gauge would be best of course. Or you could remove/test/replace that valve. (I can remove and send you one from a wrecked '97 540i).

Another approach might (emphasis on might) be to temporarily use or splice in a section of clear tubing in the low pressure oil return line that goes from the relief valve to the sump. If you see a lot of oil flow through it at idle (or when you're getting the low pressure warning), that might tell you something about the valve. Just a thought.

As I think about it more, if the symptoms seem intermittent and unrelated to anything, I'd check the electrical side first. If they are more consistently related to RPM, I'd check mechanical things first.

[geargrinder]

Oil FIGHT!!! Yay!!!!

New engines often come with "break-in" oil that is the opposite of gentle; instead, it is designed to allow specific components to wear such as piston rings so they properly seat. That oil and resulting contaminants are then quickly flushed from the engine and normal service begins.

Yeah. The old (not super super old "60's" old, but like "80's-90's" old) adage was don't run super 'good' syns for break-in cuz they're too slippery to allow good ring break-in.

The other key criteria guys like for break-in oil is lots of detergents to ensure that any and all of the fresh particles worn and washed off stuff goes straight to the filter quickly. That's another reason guys will use conventionals that have super high detergent packages like PZ.

- - - Updated - - -

BTW Nowadays I'm led to understand for various manufacturing reasons, break-in doesn't really happen like it used to... the engines and parts don't need or perform much break-in anymore - because of improvements in block wall and ring technology and mfring I expect...

[geargrinder]

+1 on the idea of checking the electrical system for the pressure switch, especially for an intermittent problem. (Badly worn bearings or a weak pump would be more likely to cause consistent problems, not intermittent ones. Same with an oil viscosity issue.)

Something else to consider... Could there be a problem with the oil pressure relief valve? It's part of the oil filter assembly. I suspect it opens at a certain pressure level, at higher rpm. If it stuck open intermittently, then the pressure would be too low when the rpm dropped. (You said the warning light goes away as soon as you increase the rpm, right?)

Since I'm a shade-tree mechanic, I always look for easy/cheap ways to test things. Using a pressure gauge would be best of course. Or you could remove/test/replace that valve. (I can remove and send you one from a wrecked '97 540i).

Another approach might (emphasis on might) be to temporarily use or splice in a section of clear tubing in the low pressure oil return line that goes from the relief valve to the sump. If you see a lot of oil flow through it at idle (or when you're getting the low pressure warning), that might tell you something about the valve. Just a thought.

As I think about it more, if the symptoms seem intermittent and unrelated to anything, I'd check the electrical side first. If they are more consistently related to RPM, I'd check mechanical things first.

I agree with all this. Confirm the warning message first. I would say that even if the motor is toast and the bearings are flowing tons of oil, the warning will show up at idle first, because the bearing losses are a fixed quantity, therefore as RPM increases the oil pump will be able to overcome them.

I do also recall people having the flicker from the pickup screen being clogged w/ crap but OP said that was AOK...

[R Shaffner]

I just checked Realoem, and I might be wrong about the location(s) of oil pressure relief valve(s).

I know there is a low pressure return line from the filter housing to the sump, but I didn't see the expected valve, spring, or piston on the diagram I looked at just now.

I DID see those components in the oil pump diagram. So the possibility of pressure release malfunction might be there. Perhaps others can shed some light on this.

(Both of these locations are before or parallel to the oil filter, and therefore filtered only by the pump screen. That might make it easier for something to get in there and interfere with their function)

[tekoo]

I suggest you follow a systematic approach to save your time and $$:

1-Measure the ACTUAL oil pressure using INPA. This will allow you to a) test whether the VEHICLES oil pressure circuit is functional or not, and b) get the actual numeric value of the oil pressure to detect true positive (truly low oil pressure) vs false positive (appropriate oil pressure in the setting of lacking or defective interpretation).
2-If INPA reveals no readings and the oil pressure circuit is non functional then I would check ground, connections, electronics, try a different switch and follow the switch/circuit/cluster troubleshooting algorithm.
3-If INPA reveals pressure that is low, then look for leak, try another oil pressure switch, replace oil filter housing, and consider all the other mechanical causes of low pressure.
4-If INPA doesn’t have the option to check oil pressure then you’d have to install a pressure gauge (as others have suggested) to figure out which route to take 2) or 3).

[geargrinder]

I'm pretty sure the oil monitoring is purely a switch (aka fixed pressure point) and not a sensor on this car/motor combo.

[tekoo]

I'm pretty sure the oil monitoring is purely a switch (aka fixed pressure point) and not a sensor on this car/motor combo.

If this is the case, INPA would still be able to detect functionality and detect if the switch is on or off.
Otherwise I would start from point 4).

[qcdstick]

This is the exact behavior my car had when the rod bearings were going out, intermittent low oil light at idle went away at RPM. Makes perfect sense if you think about it. Do yourself a favor and don't drive it until you verify proper oil pressure with a gauge. If you are very very extremely lucky you haven't damaged any hard parts and can get by with a bearing replacement and not have toasted the crankshaft. Your symptoms of strange banging noises and low oil pressure unfortunately is unlikely to be a coincidence IMO.

[JimLev]

I'm pretty sure the oil monitoring is purely a switch (aka fixed pressure point) and not a sensor on this car/motor combo.

Yes GG is correct, it's just a switch.
tekoo, no need to hook up INPA to monitor it, the oil pressure light will tell you.

[geargrinder]

This is the exact behavior my car had when the rod bearings were going out, intermittent low oil light at idle went away at RPM. Makes perfect sense if you think about it. Do yourself a favor and don't drive it until you verify proper oil pressure with a gauge. If you are very very extremely lucky you haven't damaged any hard parts and can get by with a bearing replacement and not have toasted the crankshaft. Your symptoms of strange banging noises and low oil pressure unfortunately is unlikely to be a coincidence IMO.

Yeah I agree w all this. Textbook symptoms of bearings starting to go... You can confirm oil pressure with a tester but if it shows low pressure at idle then either something is flowing more than its supposed to (most likely) or there's an oil pump failure (least likely).

[curtmcd]

Something else to consider... Could there be a problem with the oil pressure relief valve? It's part of the oil filter assembly. I suspect it opens at a certain pressure level, at higher rpm. If it stuck open intermittently, then the pressure would be too low when the rpm dropped.

UPDATE: My car has spent a lot of time sitting on jackstands, but I am happy to report that you, R Shaffner, win the prize. The oil pressure relieve valve was at fault. I've been driving a week now with no oil pressure issues, and I thank you.

The exploded parts diagram showed that the oil pressure relief valve is integrated into the oil pump. I replaced the four removable parts (piston, spring, sleeve and the circlip holding those in), plus three O-rings on the two oil tubes that come out when the oil pump is removed.

The original spring was about 1/3" shorter than the new spring, probably from age and fatigue. Although I removed the oil pump to work on it, in retrospect it looks like it could be done without removing the pump since it's faces downward next to the intake screen. Either way, safety goggles are a must while removing or replacing the circlip.

Parts were $100 with tax from BMW of South Atlanta. Of course, I wish I had done this up front, but the very loud chain noise misled both me and my independent shop. So, I have replaced all the timing chain guides and chains for no reason, but at least I know they'll be fine for the rest of this E39's life.

P/N	Qty	Price	Description
11421741129	1	3.76	O-ring 18,0X2,5MM
11421713597	1	3.76	O-ring 6,0X2,5
11421288890	1	3.76	O-ring 21X2,4MM
11411736790	1	41.04	Compression spring
11411729141	1	14.74	Piston
11411729813	1	29.81	Sleeve
07119934624	1	3.15	Lock Ring

[Chedley]

…..
The original spring was about 1/3" shorter than the new spring, probably from age and fatigue. Although I removed the oil pump to work on it, in retrospect it looks like it could be done without removing the pump since it's faces downward next to the intake screen.
..…

Very interesting find.

So, another case of a compression spring was the cause of the engine clacking that led you down the path to replace the timing chains and the guides. It sounds like the problem of the timing chain tensioner -that needs a longer stronger spring to hold up the chain and reduce its flapping against the guides, and quiet the engine on cold starts.

Would you think this is a spring that could/should be replaced as a preventive maintenance ? It seems easy enough to do, and could be definitely done without removing the whole oil pump.

[R Shaffner]

That's great! Persistence pays off. I was suspecting a clogged and sticky valve, not a shortened spring. Thanks for letting us know. At least now you know the guides won't suddenly fail on you.

[geargrinder]

Nice. Agree that this is interesting find. One-off spring failure or early trend for aging motors? Time will tell...

[Kenny1958]

I see no reason not to replace these things next time i am inside the engine again oil pressure is a very important factor.

[Chedley]

So, we are talking about replacing the piston in the oil pump. Specifically, items #2, #3, #4, and #5 in this diagram from realoem.com. And most important, the spring (#3).

You'd only have to drop the oil pan to reach this part.

https://www.realoem.com/bmw/enUS/showparts?id=DN63-USA-07-2001-E39-BMW-540i&diagId=11_1533#11411729141

[curtmcd]

So, we are talking about replacing the piston in the oil pump. Specifically, items #2, #3, #4, and #5 in this diagram from realoem.com. And most important, the spring (#3).

You'd only have to drop the oil pan to reach this part.

https://www.realoem.com/bmw/enUS/showparts?id=DN63-USA-07-2001-E39-BMW-540i&diagId=11_1533#11411729141

Exactly. The whole job could be done in a couple hours, or 5 minutes if the oil pan is already off.
For reference, this video shows the major symptom caused by that little spring: https://www.youtube.com/watch?v=kbj0fbnDnaE

[Chedley]

Exactly.
If you still have the old spring, could you measure it (length, wire diameter, outer diameter, and # of coils) and send me the measurements. I am trying to locate its specifications, but could not find it anywhere. The spring is BMW part # 11411736790.

[rdl]

Exactly.
If you still have the old spring, could you measure it (length, wire diameter, outer diameter, and # of coils) and send me the measurements. I am trying to locate its specifications, but could not find it anywhere. The spring is BMW part # 11411736790.

A heads up if you're looking to source a spring from an alternate vendor. You'll need the free length of a new spring. The old, shortened, "collapsed" spring is the root of the problem.

A coil spring's "k" factor (spring constant - the force / change in length) is primarily a function of wire diameter, coil diameter and # of coils. (also Young's Modulus Poisson ratio and shear modulus - but those are functions of the steel and won't change) See this site for coil spring equations
http://www.springhouston.com/spring-...gineering.html
So a new spring will have the same spring constant as an old "collapsed" spring.

Then consider that the spring is compressed while assembling the pressure relief valve. The distance by which the spring is compressed from its free length multiplied by "k" determines the force holding the relief valve closed, and thus the opening pressure. A new, longer spring will have more compression and thus more force and higher relief pressure than an old shortened spring, which will have less compression and thus lower force once installed.

As an aside, the equations in the site are slightly simplified. They treat the coil spring as a torsion bar wound into a more convenient shape, and this is 99% correct (99% is a SWAG, I can't recall the precise value.) A more thorough analysis also considers bending, like a beam, in the coils. But the bending effect is so small compared to the twisting that it's commonly ignored. The bending effect would be affected by spring length given the change in geometry coil to coil. But a small change in a small factor becomes irrelevant except in extremely precise designs.

[JimLev]

Just buy a spring from BMW, much easier.
In the "old days" we use to add a washer or two in with the spring in our SBC engine oil pumps to increase oil pressure.

[geargrinder]

A heads up if you're looking to source a spring from an alternate vendor. You'll need the free length of a new spring. The old, shortened, "collapsed" spring is the root of the problem.

A coil spring's "k" factor (spring constant - the force / change in length) is primarily a function of wire diameter, coil diameter and # of coils. (also Young's Modulus Poisson ratio and shear modulus - but those are functions of the steel and won't change) See this site for coil spring equations
http://www.springhouston.com/spring-...gineering.html
So a new spring will have the same spring constant as an old "collapsed" spring.

Then consider that the spring is compressed while assembling the pressure relief valve. The distance by which the spring is compressed from its free length multiplied by "k" determines the force holding the relief valve closed, and thus the opening pressure. A new, longer spring will have more compression and thus more force and higher relief pressure than an old shortened spring, which will have less compression and thus lower force once installed.

As an aside, the equations in the site are slightly simplified. They treat the coil spring as a torsion bar wound into a more convenient shape, and this is 99% correct (99% is a SWAG, I can't recall the precise value.) A more thorough analysis also considers bending, like a beam, in the coils. But the bending effect is so small compared to the twisting that it's commonly ignored. The bending effect would be affected by spring length given the change in geometry coil to coil. But a small change in a small factor becomes irrelevant except in extremely precise designs.

Ooooh nice... that's givin me a science boner.

[Chedley]

Just buy a spring from BMW, much easier.
In the "old days" we use to add a washer or two in with the spring in our SBC engine oil pumps to increase oil pressure.

Maybe we should resort to the "old days" ways, add a couple washers to increase the oil pressure in the piston of the oil pump.

I mean, this compression spring's price is listed at $9 on realoem, $40 by most online BMW parts vendors in the US, 20 Euros by European vendors, and.....50 cents at my local hardware store -pick any spring- if I only know the specs/dimensions of the spring.!! -- :-)