02 525i: loud engine rattle on start up that goes away after a couple of seconds

[jicaino]

The start up noise might be the VANOS, or it could be the lifters.

The oil filter housing has an anti-drainback valve that sometimes wears out. It's a pressed-in spring loaded check valve that is visible when you remove the housing to replace the profile gasket. BMW only sells a complete housing, but there are aftermarket check valves available. The aftermarket check valves are overpriced for what they are, but still much cheaper than buying a new housing.

The picture shows that the oil has completely drained, indicating that the check valve has failed. If the check valve is working the oil will drain only to the cross-drilled hole, leaving oil the 1/4 circle 'sump'.

The anti drainback valve itself it's pressed into the body of the housing, from the engine mating surface's side. It's not visible.

But more often than not, a good engine flush frees the valve. Also, since the OP reports having no more rattling after replacing just those 2 o-rings there's not a lot of reasons to back up removing all the oil filter housing for curing something that has gone away with the 2 little o rings that should be changed once every 2 years or so.

this is a site that sells an aftermarket valve (one of many) that has pictures of the original one and where's located.
https://vanos-bmw.com/product/oil-va...56-11421713838

[jicaino]

Also, and this isn't minor, said drainback valve only impedes the unfiltered side of the housing to drain back. If this side is good and the orings are bad, the filtered oil will slowly drain.
If your drainage issues are when you park it for over 3 to 6 hours, the issue is cured, almost 100% surely, with the orings replacement. If you stop the engine and within less than an hour your restart rattles and you experience the pressure buildup lag, then yes, the valve at the bottom of the housing is to be suspected.

[sleuth255]

That's good info! I think its my drainback valve based on what is being said here: 1: pic shows all oil gone from canister. 2: Problem occurs after the car has only been sitting for an hour or so. I'm going to call my indie about the part you linked to. He might know about the drainback issue and have an opinion on the best way to proceed.

Edit: Evan said bring in the check valve and he'll make a decision when the housing is off. He'll try to free the original check valve when its out as well. Should be easy enough to tell if the effort is successful. So, $35 with a $525 if-all-else-fails backup option. I scheduled the car for the 3rd so that'll give enough time for the o-rings to arrive. If they fix the problem then it'll be the best $.78 I ever spent on the car...

[jicaino]

Good opportunity to renew all the seals pertinent to what he'll do. Too bad you missed on flushing the engine before, sometimes a good flush is all what most of the stuck non return valves need, especially if you've been running on Castrol which is notoriously more varnish/gunk buildup prone.

[djb2]

The anti drainback valve itself it's pressed into the body of the housing, from the engine mating surface's side. It's not visible.

But more often than not, a good engine flush frees the valve. Also, since the OP reports having no more rattling after replacing just those 2 o-rings there's not a lot of reasons to back up removing all the oil filter housing for curing something that has gone away with the 2 little o rings that should be changed once every 2 years or so.

this is a site that sells an aftermarket valve (one of many) that has pictures of the original one and where's located.
https://vanos-bmw.com/product/oil-va...56-11421713838

The primary problem isn't that the check valve gets dirty, it is that the valve becomes grooved.

The valve should barely move, opening once the engine turns and only closing at shut-down. That negligible movement, combined with constant lubrication (it gets the best oil flow in the engine), should mean that it never wears out. But some valves do, suggesting that resonance or turbulent flow is causing the problem.

And to make it very clear, the oil filter housing is designed to mostly drain the oil as the cap is removed. Only a tiny pool should remain in the bottom, a low sections that spans about 90 degrees along the bottom. That pool draining indicates the check valve is leaking.

[sleuth255]

This is a pretty bad design flaw for this engine IMO. I'm putting off the maintenance on mine for a few months as I finally got the call from Bennett Coachworks and its scheduled for corrosion work starting on the 3rd.

[djb2]

This is a pretty bad design flaw for this engine IMO. I'm putting off the maintenance on mine for a few months as I finally got the call from Bennett Coachworks and its scheduled for corrosion work starting on the 3rd.

It's not a common problem, and it doesn't seem to affect longevity.
An engine slides on residual oil for the first seconds. Extending that period a few seconds is not a problem as long as it's not under significant load.

A delay building oil pressure was a bigger problem back in the carbureted days, where starting a cold engine usually involved uneven loads from running on only a few cylinders and high revs.

[ross1]

It's not a common problem, and it doesn't seem to affect longevity.
An engine slides on residual oil for the first seconds. Extending that period a few seconds is not a problem as long as it's not under significant load.

A delay building oil pressure was a bigger problem back in the carbureted days, where starting a cold engine usually involved uneven loads from running on only a few cylinders and high revs.

I disagree.

A lot depends on how long since the engine was last shut down. The longer it sits the more oil runs off the lubricated surfaces.
I'm no engineer so can't quantify how long this takes to become a dangerous situation.
A good deal of total wear occurs on cold starts and delayed oil supply will only exacerbate that situation. So longevity would be effected, sometimes dramatically.

I have personally witnessed an engine (mine) spin its bearings on a cold start. In this case the engine was oil starved because of very cold temps. Oil starvation is oil starvation, regardless of cause.
There is a reason that pre-oilers are often employed in racing engines.

[jicaino]

I disagree.

A lot depends on how long since the engine was last shut down. The longer it sits the more oil runs off the lubricated surfaces.
I'm no engineer so can't quantify how long this takes to become a dangerous situation.
A good deal of total wear occurs on cold starts and delayed oil supply will only exacerbate that situation. So longevity would be effected, sometimes dramatically.

I have personally witnessed an engine (mine) spin its bearings on a cold start. In this case the engine was oil starved because of very cold temps. Oil starvation is oil starvation, regardless of cause.
There is a reason that pre-oilers are often employed in racing engines.

While I agree on Oil starvation being a serious issue, the reason of racing engines needing oil priming (and some of them, even crankcase vacuum priming) it's due to the nature of the buildup of such engines. The tolerances are larger than around 10 times that of a normal, healthy street engine. The oil simply drains back. If they were to assemble a racing engine using the clearance we use on street engines, they'd almost 100% guaranteed seize. Propeller aircraft's engines are like that too.

[ross1]

While I agree on Oil starvation being a serious issue, the reason of racing engines needing oil priming (and some of them, even crankcase vacuum priming) it's due to the nature of the buildup of such engines. The tolerances are larger than around 10 times that of a normal, healthy street engine. The oil simply drains back. If they were to assemble a racing engine using the clearance we use on street engines, they'd almost 100% guaranteed seize. Propeller aircraft's engines are like that too.

Clearances vary according to usage. Drag race engines which aren't expected to live as long often use "loose" bearing clearances (and watery oil viscosities), nothing approaching 10x though.

[TheRide]

That is your lifters. I had the same issue and I have tried everything to fix it and they didnt work. Changing ALL lifter with brand new ones was the only fix. what also came with mine was misfire and it was only on one cylinder.

[mike okisbig]

Just an update on this: I used a bottle of the Liquimoly engine flush per the directions and the noise went away! Cold starts are nice and quiet now. Thanks everyone for their input.

[sleuth255]

Liquimoly lifter treatment quieted down my problems as well, but I consider it a temporary band-aid since the root cause is the fact that my oil light stays on for ~4 seconds after a cold start. This is not a good thing for the engine over time. Of course my o-rings showed up the day after I dropped off the car so I won't be able to dig into fixing the root cause until I get it back in ~March. I'm still waiting for the replacement OFH anti drain back valve as well so the wait isn't necessarily a bad thing.

[jicaino]

Just an update on this: I used a bottle of the Liquimoly engine flush per the directions and the noise went away! Cold starts are nice and quiet now. Thanks everyone for their input.

That's fortunate! for a while keep flushing it every other change, until you peek inside and it looks like a fresh engine (I imagine it will take about 10 oil changes in total, 5 flushes doing it every other change)

Once it's clean, a flush every 3 to 5 oil changes keeps things neat and tidy inside the engine.

[Ed CT]

That's fortunate! for a while keep flushing it every other change, until you peek inside and it looks like a fresh engine (I imagine it will take about 10 oil changes in total, 5 flushes doing it every other change)

Once it's clean, a flush every 3 to 5 oil changes keeps things neat and tidy inside the engine.

+1
I use the Liquimoly engine flush every other oil change, which for me & my mileage is once per year. I've been doing this for the last 100k miles after I started to hear some lifter taps.

[sleuth255]

So I nabbed a used M54 OFH to work on the drainback valve and it looks like it has the same issue. By comparison, the replacement valve I purchased from vanos-bmw has no potential to not seat correctly. Is the OEM design deficient or is this problem wear related? Now to the repair: how the heck do I pull the old valve out to replace it? It looks like I will need some sort of small blind hole bearing puller to do this.

Here's a video showing the problem with the OEM valve and also the replacement valve from vanos-bmw. I'm off to Napa parts to see if they can lend me the tool I need...

https://youtu.be/-Bkke0y9yKI

edit: damn. I can't find a place that can loan or rent me this tool. $35 for something cheap on Amazon but I imagine I'd get what I paid for. So plan will be to order the motionpro 15mm collet for $27 then DIY up a puller from a 4x4, nut, washer and a threaded rod that fits the collet.... I'm thinking that once I have this one done and I get the car back in March, I can recondition my original OFH and then ebay it for < $100

[ross1]

I wonder if a pipe nipple extractor, assuming an appropriate size, would give you enough purchase on that to twist and pull it out.
You have the new piece in hand so why not destructive methods? Drill the $%&^%& out.

[sleuth255]

Go animal on it is one method for sure. I can't get behind it to prevent any metal shavings from getting into the OFH though. Looks like a potentially twisty path behind the drainback valve too for small shavings to get caught in..

[djb2]

I suggest a slide hammer. That can be borrowed from tool loaner program at some of the chain auto parts stores.

You'll need a T-70 driver for the plugs that cover the internal passages if you want to fully clean the OFH. One of the plugs holds in the clogged filter bypass relief valve. The T-70 size isn't in most kits, so I bought a loose T-70 driver just for this purpose. I have never used it elsewhere.

[sleuth255]

Thanks for the info; I wasn't planning on removing the plugs but will definitely do that now.

[sleuth255]

So I pulled the faulty drainback valve today. Not too dificult. Here's pics:

15mm blind bearing collet is required. MotionPro sells them on Amazon.



Then you need to remove the fins on the old valve so you can insert the collet.




Drill a 1" hole through a scrap 4x4 aand 2x4, place over collet then attach a 3" x 1/2" bolt with washers and nut to the collet. Screw the nut down and the valve pulls right out!

[sleuth255]

Pretty straightforward to install the new part too. Dremmel cutoff wheel made short work of getting the spring out of the old valve assembly. Then I added it to the new part using blue loctite to seal the threaded halves together and drove the part in until it was flush with the rest of the OFH mounting face. Very simple process, the new valve is also aluminum and chamfered on the bottom edge to make seating a breeze. Now that I have all the tools, I'll refurb my old one then ebay it if anybody is interested. won't be until March/April timeframe though.

[philly98540]

Nice fix. The blind bearing puller did a fine job there!

[ross1]

Nice work. I always love a creative fix, especially if using 2x4s