Oil light takes a couple of seconds to go out from cold

Hi - I am a new (British) owner of a 1988 730i that I bought from a junkyard, but that is in remarkable condition (the previous owner had scrapped it because it wasn't charging; it needed a new alternator belt! I've attached a couple of pix, one of the exterior, which was taken when we were servicing the brakes and in the process of discovering it has new discs, pads and lines(!), and the other of the interior, which is in near-mint condition). It has one slightly worrying aspect (possibly not a fault, but I'd like to be sure). The oil pressure light takes about 1-2 seconds to go out the first time the engine fires from cold. After that it is O.K. until the next time it has been left for a few hours, but this happens the first start of the day. I have changed the oil and filter for a genuine filter and semi-synthetic oil, but it didn't make any difference. Can anyone shed any light on the matter for me? The reason I ask is because I am going on a 2000 mile trip round Europe in the car on Friday, and I don't want to trash the engine if it really has low pressure. Finally, sorry if this issue has been covered in the archive or in earlier posts - I am a newbie and so I was worried about this issue, but I had a look through and couldn't find anything on this issue except two links in the archive with give me a '404 not found' message. Thanks a lot - Alan, in England

Hi Alan, congrats on your purchase! :D

The 7 forums on here are pretty quiet; the best ones I've found are the 7 Series Register ones.

I'm not exactly sure what could be causing your problem, but I seem to remember seeing something about a dodgy valve in the oil canister which lets all the oil drain out of the canister/ filter area so it takes slightly longer than normal to bring the pressure up when cold starting.

Or I could be talking mince!

Yes, the small ball in the oil container gets smaller and finally disappears, some people have modified that, most have bought a new oil container.
The first seconds are very important, as the cam shafts have to get oil immy.
Sometimes the banjo bolts get lose, here a fix by gale
http://www.nmia.com/~dgnrg/page_2.htm
also check this forum for E32
http://www.bimmerboard.com/forums/e32
and the other E32 forum in the U.K. besides the one doogie mentioned already
http://www.bmw7resource.co.uk/
and check my website below, all important E32 tech tips are there.

Aaaahhh, found the info on Johan's site about this http://bmwe32.masscom.net/johan/oilf..._canister.html

And here the other fix
http://web.archive.org/web/200406031...om/results.asp
if the wayback machine works, because E32fixes.com is gone.

Low Oil Pressure Fix
Symptoms:
LOW OIL PRESS message at startup

Items needed
Wood Dowel
Small bright light
Whatever is needed to remove Oil Canister

Location of items
The oil canister is on the driver side of the engine.
How to repair
This fix shows how to fix the drain valve. Oil is draining out of the canister and causing the error message (plus it is very bad to drive a car with no oil).

If you have experienced repeated dry starts on a 735i, (low oil pressure warning minutes after shutdown), Here's a fix for the anti drain-back valve.

1. Remove filter cover & filter. If there is no oil in the housing and the anti-drainback valve is open (the valve can be pressed in).
2. Remove filter housing and inspect the inlet side of the oil feed passage. With a small bright light, you can see if the return spring has slipped over the retaining tabs preventing valve closure.
3. Grind the 4 pads away in the housing that hold in the valve.
4. Press the valve out with a blunt end rod, (screwdriver may cause damage - a wood dowel is best).
5. Disassemble the valve assembly and inspect & clean the seal.
6. Bend the corners of the spring retaining tabs out.
7. Stretch the spring an additional .25" & keep ends parallel.
8. Install the spring and bend the tabs in more than parallel.
. Cycle test the assembly 100 times minimum by slapping the valve open onto your hand to simulate high oil pressure. (My oil pressure problem began when I switched to 15-50 oil with a cold weather start).
10. Blow into the valve to check for leaks.
11. Flush the housing out completely.
12. Press in the valve carefully, (not a super tight fit).
13. Re-stake (re-flow) the aluminum over the valve edge using pointed punch but not a sharp point, (don't fracture the housing). At least 8 times around. The punched area will flow over the valve edge less than the original pad, but this is sufficient with the additional hits. This is not rocket science but, neither was the poor design of the valve.

I understand that there is an improved housing available but, it's worth a try to save $280.

07/18/02
It has been 60 days (~150 cold starts) since the repair with no problems.
pics here
http://web.archive.org/web/200406040...ow_fix&fixid=5


@Doogie: maybe that can be hosted in the U.K. board now?

Thanks very much to both of you - forums quiet or not, this is a really helpful and reassuring reply, and I appreciate it! You have both shown me how to fix it (we have a small repair shop, so it won't be a problem), and you have reassured me that it is at least limited to the first few seconds on start-up. I had read about the camshaft oil starvation risk, but I was worried about low oil pressure while driving, crank and bottom end failure, etc. - at least if I keep driving it sounds as if the problem won't be bad! We will try to do the fix before I leave though. Thanks once again for really quick replies, and also for the wealth of useful info on the site. And I have also signed up to the 7 Series register forum - although I haven't had the car for long, it is easily the nicest I have ever owned, and it won't be the last BMW, either!

Check the camshaft bearings they were prone to wear on this engine. although if it is quiet running, I wouldnt worry about it. could also be a defective switch, new one is anly a few quid.
The correct thing to do would to fit a test gauge and take an oil pressure reading. without this its really fumbling in the dark

It is the valve in the bottom of the engine oil canister, some times it wouldnt fully lock causing the oil to drip back to the oil pan, when you start the engine the the oil pressure light is on until the canister is filled with oil & this is a very common problem with M30 engines.