Hi again, 1995 525i 5SPD 283k
I changed the oil last week, using 10W40 conventional. Prior to the change I used 15W40. At cold start up, it runs great but, as soon as it reaches temp, the tapping starts to occur a lot.
As I accelerate, it goes away, as if oil is forced through the journals and reaching the lifters. I change the oil every 3-4,000 miles using the Mann filter every time. The tapping is sporadic in different areas but, it's the same tapping sound. I've heard that the tapping happens all through the RPMs but, I've driven with the sunroof and windows open and I don't hear the tapping. I can hear the tapping until I reach second gear and then it goes away.
Should I go back to 15W30, or is it time to replace the lifters? I have all 24 lifters, along with the camshaft tool ready to go but. I'm waiting to take vacation to start the project. In the meantime, should I use a different weight? It's annoying and scary that I might blow the engine driving 60 miles a day.
Thanks in advance.
I believe our engines require an oil that is ACEA A3/B3, API SL/SN rated.
Check that this is what you are running.
Probably want to get a baseline idle oil pressure to help validate overall engine health.
You may wish to investigate the oil filter tower drain back valve as a reason for startup lifter tick.
https://www.google.com/amp/s/vanos-b...1421713838/amp
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Last edited by bluptgm3; 04-09-2019 at 10:47 PM.
Sometimes I've had the tapping show up after an oil change, even when I replaced it with the same oil.
My theory: I doubt the lifters "go bad." I think they get clogged. They get a little air in them, perhaps with a little water vapor that turns into steam, making a little air pocket in the lifter. Then each time that valve is opened you'll get a little knock as the air is compressed before the lifter gets tight and opens the valve.
(In other words, draining the oil seems to help some lifters get a little air in them, that the system has trouble getting out. High mileage and oil deposits in the lifters probably contribute to the problem.)
You might find this thread interesting. We discuss curing noisy lifters and other oil things:
https://www.bimmerforums.com/forum/s...-different-oil
Also, have you tried the factory-recommended trick of revving the engine over 3,000 rpm for a few minutes? (Or putting the car in a lower gear and driving for a few minutes with the rpm over 3000.) That can help purge air from the lifters.
Last edited by R Shaffner; 04-09-2019 at 06:49 AM.
I could have been more clear about one point...
My lifter knock has always been when the engine is warm too. Never when it is cold. I think that's water vapor that has collected in the lifters. When the temp is below boiling, the water is in liquid form and doesn't compress (no knock). When the car is hot the water boils, turns to steam that does compress. Hence the knock.
Where does the water vapor come from? The moisture in the blow-by gasses each time we start the car is the most common source. Before the car gets hot the water vapor blends with the oil and turns it a little milky, until the engine gets hot and boils the water out. Then it gets purged from the crankcase through the CCV system.
And if we make a bunch of short drives in a row, without really letting the car warm up? (Like trips to a store or a short commute.) The water builds up in the crankcase and the oil, where it gets pumped all over. It stays there until the engine gets hot again, long enough to purge the steam out.
So the challenge is to get enough flow through the lifters to get all the water and air out.
Last edited by R Shaffner; 04-09-2019 at 07:11 AM.
Air shouldn't come in unless the check valve is dirty. If that happens then no amount of oil changes will help. You just need to clean them and bleed the air out. You don't even have to replace a lifter unless the head is worn by the cam or the check valve is busted.
https://youtu.be/rk1a0Sx-8WM
Last edited by fo3; 04-09-2019 at 09:46 AM.
I saw that video a while back when I was researching lifter replacement. I feel as if it may be a chain rattle. I uploaded the sound on YouTube.
https://youtu.be/bfsbUebKvmY
Let me know what y'all think.
Thanks in advance..
Last edited by fo3; 04-10-2019 at 06:16 AM.
Either a lifter(s) is clogged up and thus don't get enough oil coming in or it's just bad and leaking out oil....Even if the check valve at oil filter is bad, it wouldn't matter because the lifters would bleed themselves out - like take an example an engine thats been sitting for a few weeks - the lifters have probably collapsed by that time and it takes a few minutes of engine running to fill back up properly and eliminate ticking.
I doubt that your lifters went bad right as you changed the oil. (It's possible of course, but not likely.) It's more likely that they are a little clogged and therefore slow to fill up with oil and purge any remaining air and/or water. It's a real common problem with BMWs.
To cure it BMW came out with that shop technique of running it for a few minutes over 3,000 rpm. (The oil pressure is higher at that rpm because the oil pump is spinning faster. You don't need to maintain higher rpm because the oil pump has a pressure release valve that will open above that level.)
So, in order of increasing cost and complexity, you can:
1) Live with it as many BMW owners do from time to time
2) Try to cure/improve it by a few intervals of higher rpm driving (not all the time, just to get rid of it).
3) Use different/thinner oils to help clean out the dirty oil passages. (Since you've been using conventional oil in a car with high mileage, I'd strongly suggest running "high mileage" oil in it from now on (more detergents). And for the next change I'd at least use high mileage synthetic oil. I'd try 10-30 to see if it helps the ticking go away, at least for a time or two.
4) Remove and clean the noisy lifters (per the video).
5) Install new lifters.
In short, the higher rpm trick is free and easy, so there's no reason not to try it first.
Last edited by R Shaffner; 04-10-2019 at 07:24 PM.
As I understand these multi-viscosity oils, the first number shows the effective weight at 0 degrees C and the second shows it at 100 C. So the new oil is a little thinner when cold, and the same when hot. So it doesn't make sense that the new oil would cause the ticking sound when the engine is warm, when its viscosity is the same.
However, the process of draining and refilling oil can loosen dirt/sludge up, move it around. And when oil drains from the lifters, air (possibly with moisture) takes it's place until enough oil pressure is reapplied (and any blockage removed or pushed out of the way).
(That's why I suggested a round of 10W-30 or 5W-30 synthetic. Thinner oil and different detergents might help break up any blockage, and the thinner oil will flow into tight places a bit better, without sacrificing protection.)
Others add ATF or oil cheaners to the engine before an oil change, which I'ne never tried but some say helps.
Good luck!
Last edited by R Shaffner; 04-11-2019 at 07:50 AM.
One more thought... Does it sound like all the lifters are ticking or just a couple? If it sounds like all, then there might be a problem with oil pressure being too low. Especially if the ticking goes away at faster rpm. That's a different issue, much more serious.
Wait! Do you mean it sounds like most or ALL the lifters are making noise? That's scary. The only way that could happen would be if the oil pressure was real low, or if you had blockages in many passages and lifters. Of course, the former is more likely and should be examined first.
Several questions that are easy to test and answer:
1) Are you sure you have enough oil in the car?
2) When you turn the key to on, but before you start the car, does the oil light come on? (If not, then there might be something wrong with the warning system -- the switch, the wiring, or the bulb. I've seen that several times before.)
3) When you start the car, does the light go out right away? And does it stay off in all conditions, hot and cold, and when the engine drops to idle?
4) Are you sure everything went ok with the last oil change? The new filter went in OK? Nothing (like a rag) was left in the filter chamber by mistake?
Those are easy things to check/answer. If those don't shed any light on this, then yes I'd want to check the oil pressure. I'm not sure how to do that on that engine, but I assume there's a way to do it using the same fitting as the pressure switch. I'll reply if I find out anything before someone else does.
- - - Updated - - -
Wonderful. Does that mean you have a simpler (less thought-out) explanation for why some lifters are quiet when cold, and then noisy when the engine is warm (without being turned off or losing oil pressure while it warmed up)? I'm eager to hear it.
Have you validated oil pressure yet?
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Good news. Thx.
I Googled 'testing oil pressure BMW M50" and got some hits, including this:
https://www.bimmerfest.com/forums/sh...d.php?t=268915
I'm hoping others here have more experience testing it on that engine, and can help more.
With other engines, I've done the following:
Removed the oil pressure switch (usually near the filter).
Taken the switch to an auto parts store to get a fitting that I can attach a pressure gauge to.
Attached the pressure gauge to the car carefully, to make sure I didn't hurt the threads.
Start the engine. Check for leaks.
Rev as needed and record the results.
Others might have more details. There are other things that can cause low oil pressure, in addition to those mentioned in the thread I shared. (Oil pump and pressure release valve problems. A leak in the system...)
Still, it seems odd that any of those problems would occur right when you did the oil change, which is why I asked those questions. But strange things can happen.
Last edited by R Shaffner; 04-12-2019 at 07:55 AM. Reason: Adding comment
refer to the owners manual. depending on ambient temperatures the manual recommends different weights of oil. I had been running 10w-40 in my m60 and after switching to 20w-50 per the manual recommendation my oil pressure has been better and all of the ticking sounds my engine made have pretty much gone away when its at temperature.
Blow by gases blow into the crankcase, not upward into the cam area. The valves are closed to prevent this. Gases come up to the valvetrain through the timing cover area, under more normal pressures, and then are vented through the ccv system. There is such an insignificant amount of water in the crankcase. The crankcase is a sealed system. And when the engine is hot, all that water vapourises and gets vented out through the ccv system anyway. Water produced as a by product of combustion and that gets into the crankcase through blowby gases does so as steam anyway and gets vented out through the ccv system quickly.
The lifters are filled with oil, and they get squeezed all the time by the cam lobes. That will squeeze any gases out, and refill the lifter with oil when it is released.
The idea that water and air gets into lifters somehow, and stays there, really does not hold water. Lifters get permanently screwed basically due to oil in the springs congealing and preventing proper spring function.
And OP, don't worry, I"ve never heard of bad lifters blowing an engine.
Respectfully disagree.
Of course, that's how they're supposed to work. But lifters don't always stay full of oil. The check valve can get dirty, letting oil drain out, which lets air in. (Air was in the new lifters before they filled with oil, and air comes back in when the oil comes out. That's why they make noise, because of the play in the lifter.) Dirt, sludge and congealed oil (as you call it) can also make it harder for lifters to refill with oil.
As another poster said above, lifters rarely permanently fail (as you suggest), they just get clogged or dirty and need to be cleaned out. I agree. But BMW (and some mechanics) think there are ways to try to get oil to flow into the lifters without having to pull them out and apart. That's why BMW has the recommended shop procedure of revving the engine over 3,000 rpm for 5 minutes, and repeating that several times if needed, to help force oil in (and air out).
(It makes sense to try the easier solutions first. Of course the ticking can be solved by replacing all the lifters with clean new ones. But since they are dirty/clogged and NOT permanently damaged, there are other things that we can try first.)
And I have to disagree about the moisture too. I'm sure you've seen water dripping from the tailpipe of a car as an engine warms up. That combustion moisture is also in the blow-by gasses that are flowing into the still-cold crankcase and oil.
I gather you've never looked in an external oil separator or catch can soon after starting a cold engine, before it got good and hot. If you had you'd see the milky oil that looks more tan than black. That moisture isn't just in the separator or catch can, it's throughout the crankcase. (For models with external oil separators, BMW offers heated versions for people in cold climates, to keep that water from freezing and blocking the system.)
So yes, once the car is hot that moisture gets turned to steam and is eventually pulled out through the crankcase vent system. But before the engine gets that hot, water vapor gets blended into some of the still-cold oil. And if one makes many short trips without ever getting the engine hot, more and more water collects in the crankcase.
How would you explain lifters that are consistently quiet when cold, and noisy when hot? That's pretty common in my experience.
(Of course, none of this changes what the OP should try to cure the problem. Sorry for the side debate.)
Last edited by R Shaffner; 04-13-2019 at 07:52 AM.
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