'83 240D oil pressure question

[phil2810]

Recently (as the weather has gotten colder in Southern Virginia), I've noticed my oil pressure indication doesn't begin to register for around 20 seconds after she starts, then slowly climbs to "3". It may have alays been this way after an overnight cool down, but I didn't notice it. I frequently (every 150 miles or less) check the oil, so I know she's not low.

I do notice more engine noise before the oil pressure goes up to "3", and it sounds like it's coming from the upper cylinder head (camshaft/valves area). Once the pressure is up, it stays up, maybe dropping to 2.5 at idle, in gear (auto) after she's hot. If I put her in Park or Nuetral, it goes back to 3, even when hot.

Is there a "normal" time for pressure to come up, and if so, what might cause my symptoms of pressure lag. I use standard 15w40, whatever brand is on sale.....


Thanks,
Phil

Check the two little o-rings a the end of the oil filter cap's stem. If they are missing, they will cause a long delay.

[300SDog]

Caution is the oil guage is prone to leak on later w123's.... Have seen this happen twice. And nobody notices it until oil starts dripping on their feet. If it was me I'd pull the instruments and investigate to be on the safe side. Dinosaur oil you are using will thicken up in cold weather.

[Gurkha]

Apart from O ring check which is quite important, what is the ambient temp in Virginia in the mornings, if below 45F I would switch to a thinner 5W-40 oil which would unfortunately be the expensive synthetic like Delvac-I.

[toomany MBZ]

Twenty seconds does seem like a long time. I throw in some TufOil at oil changes, don't have a problem. I've been told that a good indication of oil pressure is how fast the gauge responds at acceleration.

[phil2810]

Originally Posted by ForcedInduction

Check the two little o-rings a the end of the oil filter cap's stem. If they are missing, they will cause a long delay.

oh crap..... is that where the little brass rings go that come with a new filter? I feel like an idiot.

I thought they went on top of the filter. Let me be sure I understand this..... You slide the filter on the cap's stem, THEN put the rings on? I was afraid the would fall off in the filter housing.

I guess while my pants are down, I'd better ask where the bigger O ring is supposed to go........?

BTW, ambient temps have been in the 30's at night.

THANKS

Phil

Originally Posted by phil2810

oh crap..... is that where the little brass rings go that come with a new filter?

No. They are two rubber o-rings. When you have the filter lid off with no filter on it, there are two rubber rings at the end of the long shaft/stem. they seal the main pressurized oil from the oil returning to the oil pan from the bypass section of the filter.

If they are missing/damaged, the filter will lose it's oil prime every time you stop the engine and will take time to refill the oil filter housing.

[pj67coll]

Originally Posted by phil2810

I thought they went on top of the filter. Let me be sure I understand this..... You slide the filter on the cap's stem, THEN put the rings on? I was afraid the would fall off in the filter housing.

The brass ring that comes with the filter is the crush washer for the oil pan drain plug. It has nothing to do with being on top of the oil filter! The two rubber O rings in question go on the end of the shaft of the Oil filter cap. As in this picture...

They do not come with the filter, you have to get them separately.

- Peter.

[toomany MBZ]

The large "o" ring goes on the filter cap. Don't know what the other metal washer goes to. Haven't used it yet. The small "o" rings in the pic from pj67coll are available from *************** 1-800-240-4620 part #0159979448

[SUNRG]

if all O-ring are found to be in place, i second the 5w-40 option - or 0w-30. i have ELF Full Tech 0w-30 MB229.5 - LINK

i live in Roanoke, VA and yesterday it was ~20 degrees when i started my 240 at 5:40am. she eagerly started and the oil pressure launches from 0 to 3 bar (with the ELF Full Tech 0w-30 compared to a 15w40).

not cheap though - but it should last a long long time.

here's an example of a TDI owner running ELF Full Tech for 19,600 miles with three lab analyses confirming optimal oil performance the whole way - LINK

i pick mine up at www.TDIparts.com

cheers!