Sudden loss of oil pressure- what is the most likely culprit?

[genphreak]

Ahem. Er. hmmm.

I changed my plugs on the M30 this weekend. Started the car up this morning (it fired straight away) but faltered slightly (strangely) straight after ignition. Then it ran fine, but I noticed a very slight and unusual noise; sounding a bit like what I would expect cavitation to sound like, coming from the oil sump.

Others may not notice it, but I know the sound of my engine well and was actually listening for exhaust leaks (as I need to replace the exhaust springs and occasionally I have to tighten the engine pipe>manifold nuts as a result).

Now the engine had not been started for about 10 days- so the 'cavitation' I thought would go away. Sure enough it seemed to quieten down a lot after 20 seconds becoming almost negligable.

BUT, I was surprised to notice the oil warning for the first time ever. (I guess) it normally goes straight out after first ignition (which I've never noticed, even with the ignition on and motor not running). :p I know, I know, pay attention amateur wrencher!.

This time the light wouldn't go away. There were no other noises and I moved the car forward a little thinking oil pressure might be taking a while if the canister had emptied ove the 10 day period. After opening the oil cap to check for oil spraying over the valves on cylinders 5&6 I found none, so I shut it down immediately and used the other car.

It ran for perhaps 90 seconds in total. Oil pressure warning was clearly displayed on the dash all this time and did not go away. No rattles or other weird noises, except for the slight hesitance on starting.

For all I know it might be the infamous canister check ball but I don't think so- I've never seen an M30 not spill oil to the top end properly and I didn't want to risk damaging the motor if there was indeed a problem.

Maybe it's my imagination but weren't M30 oil pumps (pretty much) bulletproof? Has anyone seen one fail- or the drive chain break before?

Was thinking the next test would be to pour some oil into the head (for good luck) and then remove the oil pressure switch, crank a little and check to see if oil spits out...

If this fails, is it really a matter of pulling the pan and looking for bits of disaster?

Oh, and before anyone asks, the oil level is still at 3/4 (she spills perhaps a few drops a week as most M30s do) but has never needed a any topup between changes.

What do you all think? Was I being a Woose shutting it down? Did I not give it enough time to get pressure up?

Many thanks in advance for any suggestions, Nick

[Espen]

Shouldnt take much longer than a coupple of seconds before oil pressure is up, even after a long periode of no use. I would check the oil pressure with a "real" meter before doing anything else. If you indeed have a oil pressure problem, i would check the oilpump. The oil pump chain can go to h"#, it did that on my ford.

[BillionPa]

when the pump is sitting in the pan, its pickup is submerged in oil, so it should be going everywhere.

what oil were you using?

if its dino oil, i feel bad, as it really doesnt provide much protection under those circumstances, and the oil feed lines are probably all sludged up causing the oil starvation.

if you havent noticed im a synthetic fanboy...

[632 Regal]

we should do another pole.

if you havent noticed im a synthetic fanboy...

[Jeff N.]

.

we should do another pole.

[632 Regal]

yours wasn't much better...;)

[Bleeding_Knuckles]

did you put a guage on it yet to see if its really low pressure?

[mamilapon]

When was the last time you checked the oil spray bar bolts?

[Martin in Bellevue]

yours wasn't much better...;)

That neither of you had much to offer here. :( That makes us all sad.

Gen, I'd drop the filter cannister in the hopes of finding it relatively full of oil. If it is half full, then I'd pull the oil pressure sender at the top rear of the head & crank, not start, in the hopes of catching a stream of oil in a rag. If no pissed oil, I'd then consider pulling the pan to look at the oil pump, after inspecting under the valve cover.

Good luck.

[genphreak]

When was the last time you checked the oil spray bar bolts?Thanks for all the replies guys.

I checked the banjo bolts (and torqued/loctited them in clean threads) when I did the head about 12,000 miles ago (and 2 oil changes). Need to look again of course. Oil is factory spec dino oil 20W/50 as Australia is a not cool country.

Next step will be to check for pressure and pull the cover and oil canister- I'll let you all know how this goes next weekend. I'd really like to have a remote setup, so who knows, that may well be on the cards now...

I am feeling dumb for not checking more thouroughly just recently: In the last week she was running I twice heard the head sounding like it was a bit short on oil (only under load), so I checked the level but didn't pull the timing cover or do a pressure test. I figured the idiot light should be telling me something. Hey, now I really know why it is called the IDIOT light!

So now with a clearer head (and your advice) I suspect the pump may have been starting to go... however it may also be a blockage somewhere. However if the pump is suspect, what does one do?

I think it'd be prudent to have on hand a pan gasket, oil, coolant front timing cover gasket set. To be frank I want to change the oil pump and its drive whether it ends up being faulty or not, the fear of running out of oil really gives me the willies...

Does one get a new oil pump or rebuild the old? The ETK lists the internals, ie parts 2,3 & 4 below.

I will also do 13,15 & 16 (pump chain, sprocket and tensioner arm) which of course, I should bloody well have done last time!! I have a new crank sprocket here, so hope that with these parts I'll have enerything on hand...
http://www.realoem.com/bmw/diagrams/a/u/10.png
1OIL PUMP111411317100$364.93
2ROTOR INNER111411267380$35.71
3ROTOR,OUTER111411250504$21.32
4INTERMEDIATE PLATE111411714755$2.12
5OIL PUMP COVER111411289145$82.03
6HEX BOLT WITH WASHERM6X25-Z367119915046$0.39
7PISTON111421271320$3.35
8COMPRESSION SPRING111411744324$0.88
9SPRING POCKET111411267050$3.74
10LOCK RING16X117119934619$0.17
11HEX BOLT WITH WASHERM8X30-Z317119915085$0.50
12HEX BOLT WITH WASHERM8X45-Z327119912970$0.31
13SPROCKET111411707147$44.08
14HEX NUTM10X117119900079
15CHAIN111411707163$26.51
16CHAIN TENSIONER111411705055$16.07
17BEARING BOLT111111706500$4.52
18BUSH111311706503$0.33
19CIRCLIP6,017119932842$0.04

Thanks again friends! :) Nick

[pundit]

I'd also been pulling some bearing caps off and checking the big ends and mains for signs of scoring.

[Bill R.]

you don't drop the cannister, instead you just pop the lid off and quickly look inside to see if its almost full of oil. I'd start it and run it briefly, then do that to see if there's oil in the cannister, if there's oil there then pull the valve cover and run it briefly, the ensuing mess if you have oil pressure will convince you that its ok. I suspect you don't have a problem, but since its cold in Oz right now and your running 20w50 it may take awhile to pick up if it had drained down due to the infamous oil cannister check valve fault. If so you may want to rethink that 20w50 in the winter. A lot of you guys get overly paranoid. It takes quite a while without oil pressure to hurt most motors.




That neither of you had much to offer here. :( That makes us all sad.

Gen, I'd drop the filter cannister in the hopes of finding it relatively full of oil. If it is half full, then I'd pull the oil pressure sender at the top rear of the head & crank, not start, in the hopes of catching a stream of oil in a rag. If no pissed oil, I'd then consider pulling the pan to look at the oil pump, after inspecting under the valve cover.

Good luck.

[genphreak]

I'd also been pulling some bearing caps off and checking the big ends and mains for signs of scoring.I will be looking for all signs of wear. That sounds like a good place to start once the pan is off. I feel stupid for not doing the pump when I did the head.

So may this be a lesson to anyone considering a partial rebuild of any BMW L6. It really requires doing the oil pump and drive as well as the head and timing chain.

As this necessitates lifting the motor and pulling the oil pan, the job might bigger and messier than you might be prepared for... :(

[genphreak]

you don't drop the cannister, instead you just pop the lid off and quickly look inside to see if its almost full of oil. I'd start it and run it briefly, then do that to see if there's oil in the cannister, if there's oil there then pull the valve cover and run it briefly, the ensuing mess if you have oil pressure will convince you that its ok. I suspect you don't have a problem, but since its cold in Oz right now and your running 20w50 it may take awhile to pick up if it had drained down due to the infamous oil cannister check valve fault. If so you may want to rethink that 20w50 in the winter. A lot of you guys get overly paranoid. It takes quite a while without oil pressure to hurt most motors.Bill, if you are right I will start a thread with a big bunch of flowers in it, just for you! That was one answer I was hoping for... so fingers crossed till I get to test some more- I'll add to this thread again with the details.

The car was up in the country for 10 days and it is about 4 to 8 degrees C there at night at the moment. Even though I fired her up at 3pm (20 ambient), the sump may only have climbed to 10 degrees for all I know, leaving the pump scavenging for fluid that will move.

I will take some better oil with me and may well do another oil change when I get there, thanks. We still have a few months of cold left. I really must get in the habit of changing to thinner oil in winter... I meant to do it this year but haven't driven my baby much :) Nick

[Jon K]

I skipped a bunch of BS posts, but something to consider is the oil pump nut falling off - it did it on later model inline 6 motors - don't know if its an issue with M30

[genphreak]

I skipped a bunch of BS posts, but something to consider is the oil pump nut falling off - it did it on later model inline 6 motors - don't know if its an issue with M30The M10 one on the drive gear? Crumbs, there is no washer... I wonder how it is secured (sheeer torque maybe like the crank nut?) No wonder it can come off. There must be a keyway on the gear, but still... what security is that for such a critical application.

How the hell can BMW build pumps that have bolts that fall out... weird huh!

[Jon K]

They're left hand threaded, but still.

[Paul in NZ]

nick use 5 w synthetic yer round....I hope Bills right.and or your sensor is kaput and the noise was your imagination

[genphreak]

nick use 5 w synthetic yer round....I hope Bills right.and or your sensor is kaput and the noise was your imaginationThanks Paul. Reading the Metric Mechanic (http://www.metricmechanic.com) website just now (thanks to a very kind board member that PM'd me some great info today), they describe potential problems with a pressure valve in the typical M30 oil pump that can jam, causing poor supply). Metric Mechanic even sell blueprinted oil pumps for US$300. As much as this sounds like overkill it suggests (in addition to their well-known reputation) that they kinda know what they are on about with the canister. Although this valve is less likely to wear and stick in a hot country, should she fail all the tests suggested in this thread, I will pull the canister to check it is functioning properly before looking under the valve cover. If should the pressure test still fails after the canister is confirmed to be not at fault and somehow hindering oil supply,then I'll be 'going below'...

[Ausmpower]

I suspect you don't have a problem, but since its cold in Oz right now and your running 20w50 it may take awhile to pick up if it had drained down due to the infamous oil cannister check valve fault. If so you may want to rethink that 20w50 in the winter. A lot of you guys get overly paranoid. It takes quite a while without oil pressure to hurt most motors.

I run 20w50 all year here (West aus) And even down to 1 degree C my oil light goes off as soon as the engine fires so I don't see how the oil weight is the issue here.

Oil pumps are sold as complete units here Too FYI, no one stocks the rotors or drives as usually if the pump is worn out the rotor to housing clearences are too far out to justify rebuilding the pump.

[genphreak]

OK, today I got down to work. Here's some pics... First thing to do was look for oil in the canister.

1. Opening the canister, no surprises really-
http://i96.photobucket.com/albums/l164/genphreak/canister-end.jpg
There was about a 3" puddle in the bottom- it went up to where the check valve sits at the top... (a little below actually, but that was once the filter was removed- as it takes up a little space). This pic was actually taken off the car once I had cleaned and inspected it.

No oil (not surprising) I wonder how long factory spec canisters are designed to retain their 'prime'. This one hasn't run right for 3 weeks.

Using the remote start trick (Pin 11 and 14) in the diagnostics connector I cranked a twice for 2 seconds which isn't long enough. Noticed no oil filling in the canister. Didn't test well enough, though- was actually really worried I'd already run the motor without oil.

2. Pulled the canister assembly, (monkey arms were required to work with all kinds of 1/2" and 13mm spanners and sockets under the intake manifold and around the alternator. I tried removing the alternator and gave up. In the process broke the top neck on the radiator (Doh! #1)
http://i96.photobucket.com/albums/l164/genphreak/Radiator-TopConBroken.jpg
the plastic neck was a bit fatigued after 18 years of hard work. It's been on its last legs for a while, but this time I pushed it a little loosening the alternator. Pop went the weasel's neck!

Damn, still best fix the oil problem first... grr then sort that damn neck out.

3. Used the remote start to check for oil blurting from the oil pump. As the canister is empty. Sure enough the litle hole in the bottom spat oil all over mum's driveway. (Doh! #2)http://i96.photobucket.com/albums/l164/genphreak/M30B35OilFilterRemoved.jpg
You can still see some mess after I cleaned up the gasket surfrace. Pic of the driveway is none too nice. Mum won't be happy at all... so best go now to tell her my problem is enormously better than first expected- before she sees the mess...

4. Cleaned up canister. No gunge anywhere, just like the rest of this engine everything was clean - the blockage I had envisgaged did not exist. The check valve in the top of the base section seemed to open & close neatly against the spring that is pressed in above it, holding it in place. So I didn't remove it- it's a destructive procedure one does when you notice the oil light come on for too long each morning. I've never had that problem.

If the canister empties starts emptying on me and I get the light again I will switch to a remote oil filter setup. On an RHD L6 e34, just behind the LH headlights there is an identical mounting and hole to the RH side which houses the AC filter. It's just made for a spin on oil filter that can be changed from reaching up, just under the guard...

Changed the oil to 10W40 Dino. (Castrol Magnetic). I've used this before, if it doesn't work I'll start using Synthetic. This is how 20W50 ran out of the sump- from the moment I took out the plug!
http://i96.photobucket.com/albums/l164/genphreak/20W50dribbles.jpg
THis is what I call the dribble test: And this oil seems a lot thicker than usual- ambient is about 20 degrees C (middle of the day), sump would have been perhaps 12 degrees - warming up from night before. Normally the oil spits out quite handsomely!

This is the first time I've ever had a problem using 20W50. Maybe it is cheap oil, maybe it is just too cold up here at mum's place (it is still Winter here in Australia). Best get back to Sydney where its warmer- hopefully Heidi will be happier.. like all girlfreinds, this one is often hard to please!

So now to button her up, but have to fix the radiator neck first....

[genphreak]

SO this is what I did...

How long do you think it will last?http://i96.photobucket.com/albums/l164/genphreak/Radiator-TopConFixed.jpg
Cleaned all dried coolant and crap, wiped plastic down with Methylated spirits. Used Hylomar gasket sealer, cut end off hose and put clamp hard up on what was left of the connection... Shall I start a poll? LOL

She runs to temperature just fine for now.

Interestingly, even though there was no oil in the canister at all, the dash display did not give the warning message- so the oil light went out quite quickly too. No 9 second wait either, indicating that the lighter oil really helps at startup if your check valve is faulty. Mine must have gone out so fast the display warning was not activated (this time)... phew! **FIXED**

It's a bitter sweet end though:

I am very happy not to be having to pull the sump and do the oil pump, though I know I need to prepare for it...

But I feel pretty silly for reacting to the warning like I did; ie shut down and freak out that something major broke. I just don't want to have to replace a motor I only just rebuilt last year)

Interesting canister side note though;
http://i96.photobucket.com/albums/l164/genphreak/canister-side.jpg
Side note, dunno if you can make out in the background the Greater Parrot that turned up for a drink when I shot the above pic...

Notice the 2 Torx nuts on the side? One has a small orifice leading to the far side gallery, the other goes to the output (central spindle) of the filter. I guess these are for oil pressure monitoring- so you can check post filter and pre-filter oil pressure. Has anyone used these before? They seem to be the ideal place to put a pressure sender if one wanted a pressure gaurge in the dash... though I'd say they are there for there for the shop to runs pressure checks- I sure wish I'd known about them!! (Quick Mental note- always check the TIS before doing anything...)

Anyway, I'll need to work out a way to monitor the oil pressure now so might have to use one of these... JIC the oil pump is a little weary after all. But it is on my list (as well as a radiator). At least I know the oil pump is still pumpin'... major relief!

Thanks a heap for all your comments and putting up with my freakout; All I can say is beware thick oils and cold temps - it looks like these ol' girls like to be well lubed! Nick

[Paul in NZ]

Hey Nick well done I am glad it was all sorted.So you r fix was?Where is "mums" in relation to Sydney......
wow you still have your alternator colling duct!

[BigKriss]

Glad you got it sorted out!

[genphreak]

Hey Nick well done I am glad it was all sorted.So you r fix was?Where is "mums" in relation to Sydney...... wow you still have your alternator colling duct!Hey Paul, yea I bought the duct from BMW 2 years back. They last 15 years max I guess. It cost $6 or so, its just one of those weirdly prived things. You never know with BMW Australia, $600 for a bushing used on all their cars, $6 for a custom duct pipe. Weird.

I have to stop myself, every time I goto BMW I think 'what broke' or needs to be repalced next... :D LMAO

Mum's place is up near Taree, inland; do you know Barrington Tops? Nice place, kinda cooler than most locales too :) it's very nice here atm!

[genphreak]

Glad you got it sorted out!Mate if the pump was fuX0r3d I think I'd have been writing a different post... :) And be offering you an all expenses paid trip to do some serious wrenching in the country!!! :D

[Paul in NZ]

wow i must try getting a new one mine fell of the moment i looked at it!
Dont know where you are,i will look it up!Like a lot of kiwis I have visited Melbourne,Sydney and Cairns.Spent a day In Port Douglas and a few years ago a fantastic few days at Philip Island.
Actually come to think of it its more than that,My mum and Dad lived in Melbourne for a few Years .

[Dash01]

Looking at the exploded view of the oil pump, it's hard to see how that would partly fail: Seems like the shaft or similar could fail catastrophically, in which case there would be no oil pressure whatever, so seemingly the oil pump is an all-or-nothing device.

Could the oil pressure problem be a synergistic combination of:

1. Thicker oil that flows less readily at cool temps
2. Sludge buildup on the pickup screen, in oil passages & journals
3. Balky or hesitant action of the check valve
4. Oil filter somewhat clogged
5. Oil pressure sensor balky (mine worked fine again after removing it and wiping it off)
6. Dirty oil

Has ANYBODY with an M30 engine EVER had an oil pump fail? (Lots of us have had low oil pressure lights, but how many pumps have actually failed?)

How about clogging?

Is there some sort of solvent that can be run through the system to wash out any crud that clogs the works?

[genphreak]

I run 20w50 all year here (West aus) And even down to 1 degree C my oil light goes off as soon as the engine fires so I don't see how the oil weight is the issue here.

Oil pumps are sold as complete units here Too FYI, no one stocks the rotors or drives as usually if the pump is worn out the rotor to housing clearences are too far out to justify rebuilding the pump.Thanks AusM, Bill R was spot on (as usual). I really did panic on seeing the prolonged oil warning. I believe my canister check valve has gone south- though whether it will recover in the lighter oil I do not know. The old oil was due for a change, so hopefully it will come back to life. If not I'll be needing a new cansiter and pump, I might go for a remote kit from www.bmwe34.net. and mount a standard filter near the charcoal canister, which nbeeds replacing too.. :( Nick