M52B28 328 Oil Pressure

[ffrizzo]

Hi Folks,

I having a 328i AT and on last 3 weeks I start have a issue with oil pressure light flicker when hot on idle. And I am looking for some guidance.
Yeah I know there are many threads around that but I could not have find any final words on that.

What I have checked/done so far.
When I start get this light I stoped car immediately this start flicker when I am stopping at the traffic lights. So I checked for oil leaks, check the oil level also no different noise when it's run.
Started car again to check and no light drive to home for 1km and no light. When I put on reverse light start flicker again and I stopped car again so waiting some time and turn on to properly park that.

Next day
I checked oil level and this is right above the max. So I go and check for last oil change tickets and I saw that was 8l on ticket and I thinking what ....
So I bought a oil pressure check testes.

After two days of waiting
I could measure the oil pressure with the proper tool
Starting cold this almost 50psi as this warm the pressure start drops what this is ok as I understand and after long time checking waiting I couldn't see the oil pressure drop to bellow 9psi.

New day put back the original oil sensor and get drive around to see after 40m of driving no light flicker I decide to go home and again and put on reverse light start flicker. And so I go as quickly as I can to put the oil pressure check tester back to make sure of the light it took me some time but when start the engine again oil pressure again at 9psi. So waiting and put reverse and drive and keeps on 9psi.
After some time when I put on reverse and back to N or P i see the pressure drop with low RPM(~600) I asked for a help to my wife to put on P/R/N/D so I can have a better view of the gauge and what I see is pressure drops but never bellow 5(i think it's never bellow 7)

So here is where I am now. I wan't to get it fixed but not sure what I need to do next.

What I know.

1. The oil pump nut some times fail.(but I think this fail will be more catastrophic)
2. The oil pump suction pipe some times broken and when hot this start suck air on idle. https://www.bimmerforums.com/forum/s...n-pipe-failure
3. The oil above the max can be a problem cause foam or something like that(I read that don't remember where)
4. Do bearing rods
5. Oil Spraying Nozzle(this is hard to do) RealOEM.com - Online BMW Parts Catalog item 15 and 14 depends on block type

Not sure If I should drop the oil pan and check the 1 and 2 or if I should first change the oil and put the right amount(6.5l)
Or if there is something else I need or can check.


My Car has 126k/km
I change oil every 5k/km or 6 moths(generally month happens first)
Using 10w40 100% synthetic TITAN SYN MC SAE 10W-40 | Automotive lubricants | FUCHS LUBRIFICANTES DO BRASIL LTDA


Thanks

[Eric93se]

First thing you should do is correct the oil level.

Your list is good. Another thing to add is top chain tensioner, they have an oiler on them that can get stuck open and bleed off to much pressure. Like you said not likely oil pump nut.

Engine has several oil squirters and if they get stuck open will cause low pressure. You can try an engine flush, buy a good brand, make sure engine sat over night so that its fully cold. Run the cleaner for a little longer, do not drive the car with flush in the engine.

[ffrizzo]

Yeah I forget to add the oil squirts(Item 5 on the list now). This can be a nightmare.
I Also forget to mention when I elevate the RPM just a little the flickering stop.
Top chain tensor is not to hard to change I already have it(I have a full kit for chain timing)

I have done flush on my old E46 328 I done this on every oil change but I have that since 80k/km and the e36 is way older and I get it with 122k/km and to be honest not sure if this can be a problem or not do a flush.
But maybe I give a try on flush and after I drop the oil pan to check the suction pip and pump nut.

Since I am a enthusiast and like to do this things I have a question to check rood bearings. Can I remove it to check how it's and if everything fine can I put it back and torque again?

[importbanana]

99/100 times it's nothing with the pump, but with the bearings. Most likely your crankshaft or connecting rod bearings are worn out. Maybe a previous owner damaged the engine. Too long oil change intervals, too low oil level, there's many possiblities.

Doesn't really matter anyway. You'll have to drop the oil pan anyway. Then you can check the oil suction pipe, pump and bearings all at once and then decide what do to.

[Eric93se]

Good to hear your an enthusiast. Be sure to let us know if you make improvements in oil pressure.

Welcome to the forum!

[ffrizzo]

So I still have the question. If I remove bolts to check rod bearings can I re-use this bolts again or I will need to change.
I am asking because if the case to need to replace the bolts then I will go and do the rod bearings.

Reading more the bearings I see this is mainly on rods and not on main bearings.

- - - Updated - - -

Good to hear your an enthusiast. Be sure to let us know if you make improvements in oil pressure.

Welcome to the forum!

Thank you. I am on my 4 BMW

E36(325) > E46(328)(this is with my brother now) > E39(540) > E36(328). I have bot E39 and E36 for a year and use booth on daily.
I have this E36 for 2 years now.
Also Forget to mention I already need to do the cylinder head(did it myself at home with a help from my brother).

[importbanana]

you will have to check rod and main bearings once you're in there. If your rod bearing are broken due to low oil pressure, or are causing low oil pressure, it's more than likely your main bearing are damaged, too. I don't know if you can use the bolts again, i guess not.

[JDStrickland]

Low Pressure comes from worn bearings, usually. There could be other causes, but this is the main one. What you should do is install a mechanical oil pressure gauge to see what the actual pressure is. You could be having an Oil Pressure Sending Unit (sensor) failure. I think you can acquire a mechanical gauge from Autozone on the Loaner Tool program. Oil pressure is usually something like 10 psi per 1000 rpm, so about 7.5 at idle and 35 at freeway speeds. If you can turn the light off by increasing the engine speed, then this generally points to worn bearings. Since this is a costly repair, then confirming the pressure is Step 1. If the mechanical pressure is correct, then the suspect is the Oil Pressure Sending Unit.

The mechanical gauge will fit into an unused oil passage on the Oil Filter Housing. You can screw in the fitting and see what the pressure is. Once you have confirmed the pressure, take the gauge off and return it to the store. If the mechanical gauge shows low pressure then you are likely looking at bearings.


(Sorry, I sent you to Autozone, then noticed that you are not in the USA. Autozone is a car parts store that we have, they sell tools then give a full refund when you bring the tools back, they effectively loan tools that you need once in a while but not enough to go and buy them for yourself.)

[ffrizzo]

Low Pressure comes from worn bearings, usually. There could be other causes, but this is the main one. What you should do is install a mechanical oil pressure gauge to see what the actual pressure is. You could be having an Oil Pressure Sending Unit (sensor) failure. I think you can acquire a mechanical gauge from Autozone on the Loaner Tool program. Oil pressure is usually something like 10 psi per 1000 rpm, so about 7.5 at idle and 35 at freeway speeds. If you can turn the light off by increasing the engine speed, then this generally points to worn bearings. Since this is a costly repair, then confirming the pressure is Step 1. If the mechanical pressure is correct, then the suspect is the Oil Pressure Sending Unit.

The mechanical gauge will fit into an unused oil passage on the Oil Filter Housing. You can screw in the fitting and see what the pressure is. Once you have confirmed the pressure, take the gauge off and return it to the store. If the mechanical gauge shows low pressure then you are likely looking at bearings.


(Sorry, I sent you to Autozone, then noticed that you are not in the USA. Autozone is a car parts store that we have, they sell tools then give a full refund when you bring the tools back, they effectively loan tools that you need once in a while but not enough to go and buy them for yourself.)

Yeah I am on Brazil. But thank you very much for the explanation.
And I think I am having worn bearings. I have tested with a mechanical gauge and when warm at idle pressure drops do 5psi. Also I have tested with another oil pressure sensor(from my brothers car e46 328) and again light flickers when warm at idle.
I am have some difficult to find rod bolts here in Brazil so I will need to import from US and probably the car will be seat for a month or so.

Hope that fix this issue and I do not have more serious problems.

[JDStrickland]

Yeah I am on Brazil. But thank you very much for the explanation.
And I think I am having worn bearings. I have tested with a mechanical gauge and when warm at idle pressure drops do 5psi. Also I have tested with another oil pressure sensor(from my brothers car e46 328) and again light flickers when warm at idle.
I am have some difficult to find rod bolts here in Brazil so I will need to import from US and probably the car will be seat for a month or so.

Hope that fix this issue and I do not have more serious problems.

You will have the engine out, most likely, and the bearings are the first in so they are the last out. You are looking at a big job.

[ffrizzo]

You will have the engine out, most likely, and the bearings are the first in so they are the last out. You are looking at a big job.

Yeah. I am still reading about that.
I saw lot of videos of people doing only rod bearings dropping the oil pan. Specially on S52 N54.
I know I can do the same on M52 but not sure if the M52 only have issues with rod or also with main bearings.

[jclausen]

We had a 540 that the oil light pressure light would flicker and it was probably about 7 lbs at idle we ran lquimoly engine flush then it change the oil and put a heaver grade oil in to the light has not come back on and it’s been two years

[importbanana]

I know I can do the same on M52 but not sure if the M52 only have issues with rod or also with main bearings.

If you you're in there you should inspect the main bearings anyway.

[Eric93se]

Yeah I would start with the oil flush and testing pressure later on. It's hot year round in brazil, so you can use something like 15w-40 year round.

[importbanana]

Well actually you should think about all of this first and then decide what to do.

If you want to keep the car longer then you should do the repair. Calculate what the cost of repair is and if you need a shop to do it or if you can do it yourself. Then decide if you want to invest that money and effort.

If you don't want to keep the car for longer you could just put the thickest oil available in and then forget about it. It will probably last long enough until you get another car.

[ffrizzo]

Hey everyone

After long time I can work on connect rod bearings. Car stay on garage for long 2 months
Here are the bearings in order from 1 - 6 and start with bottom/top for each cilynder.
IMG_6707.jpgIMG_6709.jpgIMG_6711.jpgIMG_6711.jpgIMG_6710.jpg


Unfortunatelly I couldn't finish all the work over the weekend I have a help from my brother but since this is first time I am doing this at home I am take more time to analysis everything.
Also after put reassembly all new bearings and put the oil pump back I fell the engine is way heavy to rotate is that normal? Or I am doing something wrong and I should check?
I follow Bentley manuals and also have TIS to compare/validate info to make it correct.

PS. Here are some pictures from car and work done BMW E36 328 Album

[JDStrickland]

It will be tighter because the bearings are new. How did the crankshaft look? Also, you should have used Assembly Lube so you are not turning metal on metal as you put the remaining parts back in. With the connecting rods worn like that, you should measure the crankshaft journals. But, you put the rods back in already, so you can't measure anymore.

[ffrizzo]

I visual inspect and crankshaft and that looks normal no damages. Yes I used assembly lube to assembly everything back.

[importbanana]

If you used the correct size bearings and no oversize bearings, used lubrication or oil to assemble and torqued everything according to the manual, then it should be alright.

[spyderg0d]

It should NOT be hard to turn by hand with the spark plugs out. You should be able to turn it easily with a 6" wrench on the crank bolt.

Easy mistakes to make:
Caps on backwards. The tangs go together, not on opposing sides.
Mix match caps,.. biggest no no. The caps are not interchangeable between rods.
Not fitting the bearings evenly on the places so they crush improperly when installing. This leaves material and flake dragging on the crank that will end up destroying the bearing and possibly journal somewhat quickly.

Not putting the same rod/pistons back in the same bore also leads to improper clearances.

I suggest, you order some plastiguage. Green I think is right. Use it on both top and bottom of every rod. Make sure you are in spec everywhere, not just on the bottom side of the journals.

[ffrizzo]

Yes. I used red line assembly lube and plastigage all connect rods.
I also done one by one to avoid any mistake to change caps between.
And I take care to properly seat bearings line up on the borders on cap and on rod.
Hope I did not mess with anything on my first bearings work.
I had same fears when I did the cylinder head on e36 and e46

[primo107]

I have 2 or 3 threads on this somewhere describing my own car having the same problem.
I did the sensor,
then both bearings
then checked the pump and cleaned the pan,
then new oil filter assembly
then 10w60, 5w50, 10w40
Only thing left to do was to change the valve that is inside the engine.
After a bit the issue went away by itself. Measuring oil pressure showed no problems when it was finally done.
The problem appeared again after month and then again. I hooked a permanent gauge to monitor it.
It seems like there are some variations in the bmw sensor - some will trigger on 0.8 some on 0.5 or 0.4. Third time this issue appeared I went ahead and got a new sensor and tested at the hottest temp beating the car for an hour around the limiter, the oil stayed at 0.6bar on idle and 4 when pushed hard (thinks that the limiter as Ive seen cars do 6).
All my sensors were bmw oem but they all looked a bit different.

[ffrizzo]

Rod Bearings working done. But still getting low pressure at idle when warm. One thing I am notice now is my rpm is low around 600rpm to 700rpm max when in R or D, when I put on P or N I saw the rpm go higher and oil light stop flickering. (I am having problems to use scanner on e36 they keep connecting and disconnecting and I am using same scanner on e46 and on e39 without any issue).
Some more pictures bellow.
So now I am thinking if the RPM is to low at idle and on R or D

IMG_6683.jpgIMG_6685.jpgIMG_6691.jpg

[spyderg0d]

Sounds like oil pump is going out as well.

- - - Updated - - -

Or the sensor is a bit touchy.

[importbanana]

Since D puts some load on the engine, there normaly is some rpm difference on some cars.

With the rod bearings looking this bad, you can expect the main bearings to be in similar bad shape, but you didn't do the main bearings, so why did you expect the low oil pressure to be fixed?