Uh oh, it's not the timing chain guides

[geargrinder]

I would NOT use a "at my local hardware store" spring. The stuff they stock is generally crappy as hell.

I WOULD potentially avoid the $40 by looking for a proper quality engineering spring following the principles that RDL discusses.

[R Shaffner]

First, kudos to you, curtmcd, for being persistent to the point of getting a new spring. (I could easily have opened up the valve, made sure it was clean and clear, and put it back together without even suspecting a compressed spring as the problem.)

Second, waiting to discover low pressure at idle seems like a bad idea. It's not like waiting for the VANOS noise to fix it. If the spring isn't holding pressure at idle, then it certainly isn't maintaining the desired pressure when the engine needs it most -- at higher rpm and under load. For many of us, that means the engines could be operating at lower oil pressure for many years and miles.

Could other things, like noisy lifters, be a symptom of generally low oil pressure? (I've often wondered why BMW's had that reputation. Perhaps one of the root causes is this spring.)

I'll be pulling my oil pan pretty soon to check for signs of failing guides. I plan to replace the spring with one from realoem (easily worth $9 to make sure I've got the right part). I'll compare the springs before I do and report back, probably in another month or so. We should all do that as we can, and ask the e38 guys to do that too.

[R Shaffner]

Wait. This is the first time I've actually tried to buy something on realoem. It now appears that i can't. Is that right? They just list parts and don't sell them?

[JimLev]

Wait. This is the first time I've actually tried to buy something on realoem. It now appears that i can't. Is that right? They just list parts and don't sell them?

You are correct. Just parts lists with p/n's.
Their prices use to be pretty accurate, not anymore.

[R Shaffner]

I have a '97 540 parts car that made it 230,000 miles before getting totaled. I just pulled the oil pressure release valve and the spring looks fine. On the top is my old one. On the bottom is a new one I bought (and will now return.)

Oil Release Valve Springs.jpg

Some details:
Length of just the spring (both the new one and my old one): 102 mm
Length of spring w/ piston: 107 mm
At rest compressed distance: 42 mm to fit under the circlip

In other words, the 102 mm spring is compressed by 42 mm to a resting length of 60 mm. The spring wire is 2 mm thick.

FWIW, that car had a steady diet of Rotella 15w-40, spec for that year.

Later I plan to measure the force required to compress the spring that much, just so we know about what the release pressure is supposed to be.

(I still plan to check the spring on my '02 when I pull the pan at the next oil change.)

[Chedley]

Great.
Can you measure the outer diameter of the spring (old or new) ? Also, any idea on the spring material ? I'd think the new spring needs to be stronger, so that it will not collapse or weaken easily with thick oil or time.
Also, given the above data, the material type, and the number of coils (21), you should be able to "compute" the spring's compression force.

[JimLev]

Along with the spring material your going to need to know how it was tempered.
It won't be easy to compute, probably easier to just wait for R. Shaf to reply with the spring force.

[R Shaffner]

OK. I have more data to share, and a confusing discovery.

First the data: The spring diameter is 15 mm. The piston diameter is 20 mm. With 25 pounds of force the spring is compressed to 59 mm (1 mm more than its normal compressed position in the car with no oil pressure).

The area of the piston is just under 1/2 square inch, so the math works out to a release pressure around 50 psi.

EXCEPT for one thing that I just discovered... There's a 3 mm hole in the top of the piston, as shown in the photo below.

Hole in piston.jpg

This blew me away. So the release pressure will depend on how hard it is to push the oil through a 3 mm hole? And that will depend on other things, like viscosity and temperature. Really? I'll have to ponder this a while, or wait for someone here to enlighten me.

[philly98540]

Release pressure would be almost the same if no hole, but with the hole it needs more rpm to get there.

[JimLev]

An oil path thru the pump might help.

[R Shaffner]

Wait -- It just occurred to me that I didn't examine the walls of the cylinder, so I don't the mechanics for how the oil pressure is released. All I know at this point is the spring on my old 540 is ok.

[TheAngryBear]

Isn’t the normal oil pressure (cruising) about 40 psi in the M62TU? 60 at cold and 10-20 at temp idle? Pretty sure I am reading this right, 50 by the spring is above “standard” (10 psi at idle) and therefore the spring maintains unless WOT (60+ psi).
https://www.newtis.info/tisv2/a/en/e...supply/60gCpT4

2001 750iL DD74441
Stock

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

[Chedley]

Well TAB, (1 bar = 14.5 psi) ; that TIS specifies a minimum pressure of 0.5 bar or 7.25 psi, with engine at idle speed and oil at operating temperature (whatever that temp is. We know the M62TU does not really care or measure oil temp !!) .

Regulated pressure (presumably the max pressure?) is specified at 4.5 bar or 65.2 psi.

So, I'd say the spring from the '97 540i (50 psi as computed by R. Shafner) is below the standard or regulated pressure.

Therefore, we need a stronger new spring to exercise pressure at the regulated 65.2 psi, and avoid the clacking noise that actually signals oil pressure drop, and that has nothing to do with the timing chain guides..!!
What do you think ?!

https://www.newtis.info/tisv2/a/en/e39-540i-lim/repair-manuals/11-engine/11-40-oil-supply/6890BgR

So, the new stronger spring should have the following specs:

Length at rest : 102 mm
Length compressed: 59 mm , with a compression force of 32.6 pounds.
Outer diameter (width) : 15 mm
Number of coils: 21

I will head to my "local hardware store" and see if I can find one for 50 cents...

[R Shaffner]

Sorry guys. I was tired and multi-tasking last night. Should have waited.

With 25 pounds of weight, the spring compressed from a length of 102mm down to 59 mm. So the compression range was 43 mm. My math still works out to about 50 psi to move it from the resting position. The release pressure might be higher (I don't know how the other end of the cylinder is configured).

And the part I was looking at wasn't the piston. (Duh.) The piston must still be inside the valve. (My hands got oily and some of the parts came flying out, but prob not the piston, or seal.) As Jim said, the part I was looking at with the hole was just the piece that held the spring. The hole lets the oil go back to the sump.

The OP, cutmcd, said his spring had gotten compressed so it produced less pressure. That was my concern. But now I have an older spring with more mileage that looks fine. Good news, that we don't have another weakened spring. I'll still check the one in the car I'm driving and report back in another month or two.

[TheAngryBear]

Chedley - it could be that the regulated is the standard pressure but I still don’t think that justifies putting in a stronger spring. Since the spring serves to keep the valve closed until exceeded, it stands to reason the regulated pressure should be when it is open (spring compressed) and those numbers align. Don’t forget that the spring compression strength changes with distance. The 50 is at closed, so some delta pressures is required to open X amount and delta+ to Y. In this case 5.8 lbs/cm. A stronger spring wouldn’t allow pressure relief until to late (greater pressure on seals and gaskets), a weaker to early (not enough pressure to live the engine parts).

Edited: updated info on spring compression

2001 750iL DD74441
Stock

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

[curtmcd]

Hi guys,

I made a major mistake and am bummed out. In a weak moment I traded in the E39 while buying a 2019 Chevy Bolt. Even with low miles and excellent condition, KBB value was $2K trade-in / $4K private sale. They gave me $3500 for it and whisked it off to the boneyard. Hopefully someone finds it who gets another 75,000 miles of enjoyment. My friend helped me clean it out, and (unbeknownst to me) took out all the tidbits (jack, flashlight, tool kit contents, etc), so the new owner will be missing those. Sigh.

This after I had put $900 new tires on last year, did all the work learning about it, getting $200 tools and replacing the $1700 timing chains and guides and misc, figuring out the low oil pressure issue, repairing the plastics around the fenders, replacing the tail lights and even paying $100 to have a small dent taken out of the roof. It was cherry again, and then... gone.

So I no longer need the camshaft alignment tools or crankshaft holder. I listed those cheap on eBay if anyone is interested.
https://www.ebay.com/itm/BMW-M60-M62...t/293018283396
https://www.ebay.com/itm/293018425578

I had made two jack stand pads out of hockey pucks. If anyone would like those I'd be happy to mail them out.

I have a new $28 trim piece for the front window that I had not yet installed. Mine had gone all sticky (silicone should be banned from anything expected to last more than 10 years).

Finally, there is a $41 set of eight NGK 2288 BKR6EK spark plugs I'll never use.

-The Traitor

[geargrinder]

Hi guys,

I made a major mistake and am bummed out. In a weak moment I traded in the E39 while buying a 2019 Chevy Bolt. Even with low miles and excellent condition, KBB value was $2K trade-in / $4K private sale. They gave me $3500 for it and whisked it off to the boneyard.

Here's the real math on that.

They gave you "$3500"? Ha. No they fkn didn't.

They got $500 for the car from the JY at best.

Really they gave you :
$500 for the E39 which they recouped immediately.
$3000 phony trade-in-inflation-pretend-number that would have been called a ‘cash discount’ if you bargained and paid cash.

That’s why I always tell people “tell them you want to do a cash deal first, and get a real best price, then and only then bring in the trade-in car”. The “ZOMG they gave me $10k for my POS trade-in!” Is almost always total bullcrap.

[R Shaffner]

Curtmcd,

Thanks for letting us know. And from this thread we've learned to be on the lookout for weakened oil pressure springs.

FWIW, I was wondering about what damage might have been done to that engine from having low oil pressure for sustained period, especially at higher rpm. (If that weakened spring allowed the light to come on at idle, then it probably allowed the pressure to be low at all other times too, especially when strong oil flow was more critical.) In short, other problems might have already started in that engine.

Good luck with your new car.

[curtmcd]

Yeah, I know I didn't get 3500 for it. High pressure dealer situations suck. Constant string of lies, deceptions, delays, and hostage keeping that's hard to take, but I was well aware of it. There was also another 3500 "dealer discount" that seemed like a fixed number across various dealers. With the 7500 federal credit, 2500 California credit, 900 PG&E credit, and Chevy still losing 5000 per unit, I got a great deal on an amazing car. But I should have left the E39 out of it. In 2008 I bought a beautiful Tundra for a truly amazing discount ($26k OTD all taxes/fees). I had to spend an entire day at the dealer with a break for lunch where I brought them burritos, all the while constantly threatening to leave, and actually doing so, only to be flagged down on the way out of the lot twice. Fun!

I have no reason to believe any engine damage occurred since I kept the car out of commission ever since the very first "OIL PRESSURE STOP DRIVING" alert which was also the first time the noise was noticeable. AAA'd it to the highly regarded indy shop that failed to diagnose and quoted me first 9500 then 6000, so I AAA'd it back and put it up on stands for 4 months for what amounted to a $41 problem. The engine is now super quiet and never had any spec of anything in the oil. Oh, except on about the 3rd time I took off the oil pan I found a large paper/plasticized label in the sump! I don't remember any of the timing guides having a label. Sheesh! And since I'm in full disclosure here, I also stripped the oil pan drain bolt, first time I've ever done that on any vehicle. ECS Tuning had thrown in a fancy black magnetic plug, and like an idiot I figured why not. It wouldn't torque to spec, kept turning past, then big shards of epoxy or powdercoat or something were coming off that POS. Maybe the case isn't stripped, I don't know, I lost the old bolt, it held oil, but talk about piss me off.

[R Shaffner]

Just to follow-up on an earlier post...

I checked the oil pressure release valve spring on my '02 540i that has 180,000 miles. It was the same length as the one on my '97, which was the same as the new spring. So my springs are good, and it looks like the OP had a rare failed spring.

However, there were a few pieces of chain guides in the oil pan, so now I too have launched into the guides/VANOS drill.

[Chedley]

Good to know that your springs are fine. Though, you did not have the disturbing ratting noise similar to what the OP posted in his first posting-- That was the result of oil pressure release valve spring collapse, mis-diagnosed as guides failure.

Interesting, as I am about to do the annual oil pan drop, so I will check out that oil valve spring.

But it looks like you have the classical -and certain- sign of timing chain guides failure : bits of plastic in the oil pan.!! Time for the big job. Good Luck...

[R Shaffner]

Good to know that your springs are fine. Though, you did not have the disturbing ratting noise similar to what the OP posted in his first posting-- That was the result of oil pressure release valve spring collapse, mis-diagnosed as guides failure.

Interesting, as I am about to do the annual oil pan drop, so I will check out that oil valve spring.

But it looks like you have the classical -and certain- sign of timing chain guides failure : bits of plastic in the oil pan.!! Time for the big job. Good Luck...

It was odd -- there were only 2 guide pieces in the pan, 1 1/2 long in total. I wondered if I could wait. Went ahead. Then I found that 40% of the U-shaped center guide plastic was gone on the driver's side. A 6-inch piece was protruding out and about to drop. A 4-inch piece was in the oil pump chain cover. I caught it just in time.

[southsouth]

20200815_170823.jpg

I just pulled my oil pump. The spring referenced before, the 10.2 cm one is pictured here as the bottom of the two. But no where on this thread is mentioned the other spring. I measured it to be 6.5 cms. Nor does it show up on realoem diagram... here is where it plugs into, you can see it sticking out top right. Screenshot_20200815-203433_Video Player.jpg

Also can someone explain how these oil pumps and cylinder springs work to increase oil pressure at low rpm?

[R Shaffner]

Not sure about that second spring. As you might know, the oil pump is supposed to produce sufficient pressure on its own, provided there isn't a breach in the system that lets too much oil leak out. The springs are there to release pressure when it's too high, like when the engine is spinning at higher rpm.

[southsouth]

Not sure about that second spring. As you might know, the oil pump is supposed to produce sufficient pressure on its own, provided there isn't a breach in the system that lets too much oil leak out. The springs are there to release pressure when it's too high, like when the engine is spinning at higher rpm.

Yes I agree. It relieves high oil pressure. But ppl have been saying in my other thread it helps with low oil pressure.

I guess my search for the sound continues. I have a rattle from idle to 1400 rpm.