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Discussion Starter · #1 ·
Hello again :). I am having another problem with my car. When i start my car nowadays it seems to run just fine. However, after driving the car for a while (letting it heat up), once the car comes to a stop the red engine oil light starts to flicker on. If i press the gas, it goes away. If i keep coming to a stop, the light eventually becomes solid and the sign "STOP ENGINE OIL PRESSURE" or something similar comes on. Ive checked if i have engine oil in the car using the dipstick before and after each of these drives. (and obviously im having to limit my driving to very little, pretty much to garages and back). i took it to a few places and no one is wanting to fully diagnose it as of yet, but they keep saying its either the "oil pressure switch?" or the "oil pump". i am hoping its just the switch causing this as its the cheaper of the fixes (im assuming)? What do you think it might be? i dont hear any sounds when this happens, however i do feel some vibrations very slightly when this happens and most probably its in my mind because no one else in my car feels it nor do the mechanics. If it is the oil pump, how much do you think it would cost to replace it (in terms of labor fee). i heard from someone that its relatively simple to change the oil pump in these cars as all they have to do is take off the oil pan and the pump is accessible easily, is this true? Could it also be something else?

On a side note, for some reason it feels to me as if the car is heating up a bit too much. The engine temperature meter is always half way between cold and hot (when the car is warmed up) and never goes above that, but it feels to me as if its radiating a lot of heat compared to other cars ive seen. Is this normal to the e39? Sometimes when i drive it and the car warms up, it sounds like a truck (im assuming the sound is coming from the fan).

My Car:
1997 540i
V8 EFI DOHC
using 10w30 mobil 1 engine oil
 

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Sometimes the Plastic Oil Filter CAP misses a few parts at the very tip causing this Oil Pressure Light.

Remove your Plastic Oil Filter CAP and compares against a known good picture.

I changed my Plastic Oil Filter CAP at 100K because it cracked when I opened it.
But at 12 yrs and ? 120K, replace it anyway, it is Plastic!
$28 at dealer or online.
 

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The only way to check this out is to connect an oil pressure gauge at the oil filter, and compare actual pressure with the specs.
 

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^^^^Correct. The oil pressure switch is removed, and the pressure guage is installed in its place. The specs for oil pressure for the 540i are:

Oil pressure at idle speed with engine at operating temperature: minimum .5 bar

Regulated Pressure: 4.5 bar
 

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Discussion Starter · #5 ·
if it is lets say the oil pump, how hard is it to replace? is it labor intensive? or is it a [relatively] simple job of lets say just dropping the oil pan without having to remove anything else, and changing the oil pump?
 

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Do a search for "loose oil pump bolts" . If you don't get any hits...go to www.e38.org or www.e38.org/e39 and do a page search [Ctrl+F] and type "oil pump" as your search words...there was lots discussions about this in years past about the early m62 engines and loose oil pump bolts which would cause the warning lights you've been getting.

Please don't wait to check if your bolts are loose...it could be catastrophic if one or more of the bolts drop out and get caught in the chain...or the pump drops.

There are THREE bolts that support the oil pump...two are easy to see because there out front (see pics below)...and there's a 3rd bolt that is behind the pump which is easy to miss:

two front bolts are circled in yellow: images by John (Oxford Files)


and here's the 3rd bolt located behind the pump
 

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Oil Pump lasts the life of the engine.
Replacing the oil pump is a labor-intensive job.

Go and look for more obvious causes (Bad Oil Filter Cap as I mentioned!).
Absolutely!
 

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I thought it was a snap to remove the oil pan on the 540 models--it's a major under taking on the i6 cars.
If memory serve's there was some problems with oil pressure sensors--best way is to go through all the motions--replace the cap as cn90 stated--check the pressure with a mechinical gauge and then if all else
fails--the oil pump bolts--I wouldn't drive this thing far --if at all until the problem is settled
 

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What weight of oil are you running and is it always on the dip stick at the correct line?

I too say forget the oil pump. The light comes on when stopping because the oil goes to the front. if its doing that on easy stops you probably need to add 1 or 2 qrts more oil.

Add two quarts and call me in the morning.
 

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^ I realise that disagreeing with Franka is a major thing in these forums, but I would have to say that if the light comes on when he pulls to a stop, it may be because the engine rpm goes down to idle (550rpm or whatever the idle speed is supposed to be) and oil pressure goes down in proportion because the pump is driven from the engine crankshaft assembly.

At idle, the oil pressure should be around 0.5 bar (or 7.4 psi) and at high engine rpm it should regulate at 60-65 psi.

if the light comes on at idle speed, this may be because at idle there is below 7.4 psi because of some problem or inefficiency with the oil pump. Once engine speed increases, pressure will always increase, and thus the light will go off.

I dont mean to disagree with you Franka, and I have a great deal of respect for your answers in these forums, but thats my alternate theory to what might be happening. Since the oil in the sump will more or less level out after say 10 seconds of stoplight idling.

No disrespect intended :)
 

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at the op: I am having the same problem with my car as well. I am not sure what is causing the egine pressure light to come on. If I figure it out I will let you know. Meanwhile, If you figure it out before I do let me know.
 

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^ I realise that disagreeing with Franka is a major thing in these forums, but I would have to say that if the light comes on when he pulls to a stop, it may be because the engine rpm goes down to idle (550rpm or whatever the idle speed is supposed to be) and oil pressure goes down in proportion because the pump is driven from the engine crankshaft assembly.

At idle, the oil pressure should be around 0.5 bar (or 7.4 psi) and at high engine rpm it should regulate at 60-65 psi.

if the light comes on at idle speed, this may be because at idle there is below 7.4 psi because of some problem or inefficiency with the oil pump. Once engine speed increases, pressure will always increase, and thus the light will go off.

I dont mean to disagree with you Franka, and I have a great deal of respect for your answers in these forums, but thats my alternate theory to what might be happening. Since the oil in the sump will more or less level out after say 10 seconds of stoplight idling.

No disrespect intended :)
That too is what I was thinking as well... however the pump could be pumping just fine but the only time the loss in pressure is noted is when it is pumping at idle.... my experience with bad pumps has been all or nothing however which leads me to believe that this may not be the culprit in this case.
 

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Discussion Starter · #14 ·
lude, what oil are you using? this is a long shot, but i dont think the pump is my problem either. i was doing some research and i think i may just be using the wrong grade oil. Im using mobil 1 10w30 synthetic, i was looking into it and its not ACE-93 (or something liek that) nor LL-01 approved. according to some sites, these oils thin out wayy to much when it gets hot or at normal operating temperature. im going to try changing my oil with bmw oil (at the stealership) and see if it works out. if not, then im going to go look for a higher paying job lol and change the oil pump. (ive read at some forums that people had problems similar to this and realized their oil wasnt ll-01 approved and changed oil and the problem went away)
 

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Why don't you do a simple thing:
- Get an OEM Oil Filter and change it at home, it takes a few minutes with the 36-mm socket.
- When tightening the cap, just snug with 2 fingers on the ratchet, no need to go to 25 Nm as the book says.

Your Oil Filter may be partially clogged.
 

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lude, what oil are you using? this is a long shot, but i dont think the pump is my problem either. i was doing some research and i think i may just be using the wrong grade oil. Im using mobil 1 10w30 synthetic, i was looking into it and its not ACE-93 (or something liek that) nor LL-01 approved. according to some sites, these oils thin out wayy to much when it gets hot or at normal operating temperature. im going to try changing my oil with bmw oil (at the stealership) and see if it works out.
I don't think it'll thin out too much; 30 weight is 30 weight, unless it doesn't comply with basic standards.

However, in NYC, 10w is a bit heavy for cold starts. It doesn't matter what the "spread" is with synthetics, as there's no "stretching" polymers in true synthetics to break down. 5w30 BMW oil is fine; I use Mobil1 0w40 myself due to limitations in oil supply (I'm not going to pay $13/qt for Amsoil 5w30, sorry***8230;not to mention the special order I'd need to place with the unreliable store that sells it.)

You can buy the BMW oil and change it yourself, saving you a huge cost. Using a BMW OEM filter (you could buy it from EACTuning or another board sponsor) is very important, with any oil. I'd go with a LL-01 approved oil if there's a problem, before putting in BMW's unobtanium-enhanced oil.
 

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lude, what oil are you using? this is a long shot, but i dont think the pump is my problem either. i was doing some research and i think i may just be using the wrong grade oil. Im using mobil 1 10w30 synthetic, i was looking into it and its not ACE-93 (or something liek that) nor LL-01 approved. according to some sites, these oils thin out wayy to much when it gets hot or at normal operating temperature. im going to try changing my oil with bmw oil (at the stealership) and see if it works out. if not, then im going to go look for a higher paying job lol and change the oil pump. (ive read at some forums that people had problems similar to this and realized their oil wasnt ll-01 approved and changed oil and the problem went away)
I used mobile 1 5w-30. And for my heating problem , I figure out what was the issue. My heater control valve went bad. The cheapest I found it was 220. Bmw priced me 495 bucks. Sad Story!
 

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So what is so special about LL-01 or whatever the code is?

Maybe some of the oil specialists we have on this forum can answer that so we can all understand.
 

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Discussion Starter · #19 ·
UPDATE:

I got my oil change done (since it has been 6 months anyways). To try to be safe, i went to an indie BMW shop and put in ll-98 approved A3 oil (castrol 5w40). So it didnt solve any problems, although with the thicker oil (castrol 5w40) its taking a little longer for the oil light to come on.

Lude, how long did you have your oil light problem for? do you still drive your car around? did you find a solution? .. and is your engine still intact?\\

Do you think a bad thermostat is making the car slightly overheat without me knowing (since the meter isnt going past half way) and the oil thinning out because of excess heat and losing oil pressure?

the shop also said that my timing cover gasket might be leaking... is that going to be very expensive to fix? (they quoted me $800 and i said il come back... i think they are ripping me of?)
 

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Now you have changed the Oil and Oil Filter and the problem persists.
Then my best guess is defective Oil Pressure Switch.
Very easy to replace for V8 engine:

Up to 09/1997: 12611731499
http://www.realoem.com/bmw/showparts.do?model=DE63&mospid=47588&btnr=11_1591&hg=11&fg=30&hl=38
http://www.rmeuropean.com/Part-Number/Oil-Pressure-Switch-__12611731499_TRW_85647CDD.aspx
$19.00

From 09/1997 ---> 12617568480
http://www.rmeuropean.com/Part-Number/Oil-Pressure-Switch-__12617568480_TRW_85647CDD.aspx
$6.00
 
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