Hi Folks,

wondering if this is normal or not.

I usually drive my 82 240D approx 20 miles before changing the oil. I don't do this purposely but because thats how far it is to get to my parents house where I can change it. Thus the oil is nice and hot when its drained.

Sequence is that I pull the drain plug and drain the pan. While thats happening I remove the filter, clean the filter canister lid - install new o-rings and re-install the filter and canister lid. I do not fill the filter with oil.

Then I re-install the drain plug and fill it up with about 6.5 quarts. check for leaks and check the dipstick and start it.

I've noticed on the last two oil changes that when i start the car it it does not build oil pressure, the engine will actually start to clatter. Then I shut it off. Restart it - engine starts to clatter, and it will build half a bar of oil pressure slowly, then rise to 3.

This all happens in a matter of 10-20 seconds but seems like forever when its happening. Am I doing something wrong? this is how I have always changed oil.

Should I be pre-filling the filter canister with a quart of oil or something?


For reference when the car has sat for any period of time (even over night) it fires up and immediately builds 3 bar oil pressure. Hot oil pressure is 1.75 bar and coming off the high way on a summer day when I've been cruising at 65-70mph it will be a hair above 1 bar, then rise pretty immediately as the oil cools a bit to 1.5 bar.

Lastly, why do I always get two large o rings in the filter kit? one is thick and one is usually thinner.. I just use the thicker on under the canister lid and pitch the other one?

thanks!

I see no flaw in your procedure. The clattering seems wrong though. What kind of oil are you using? ...weight?

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Shell Rotella 15w-40 (non synthetic)

Have you ever changed the two small o-rings on the shaft under the canister lid? They will get hard and no longer seal well and should be changed every third or fourth oil change.

Not in the filter change kit but are available at the dealer or any big box parts place as part of a metric o-ring assortment.

If you don't want to wait for the oil pump to fill it up, fill it yourself. (Install the filter element first.)

Believe it or not, one oil filter can have multiple applications. The part that doesn't fit is for an engine that you don't have.

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When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

The oil pressure being slow to build after an oil change is normal. The oil pump has to fill the oil filter housing before anything makes it out to the engine. Your changing procedure is the same I use and my car takes about the same amount of time to fill the canister as well. Mine doesn't start clattering though - that part doesn't seem normal. As has been suggested, if you don't want to wait for the pump to build pressure, dump some in the oil filter housing. Be aware that you won't be able to fill it since you have the stem out for access (don't go over-filling the crankcase trying to fill the filter housing is the point here...).

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Roger Diseasel.

The oil canister cap makes an airtight seal when in place. Any oil poured into the canister without the cap in place will simply drain into the crankcase.

It's all a matter of timing. If you wait half a day to install the cap, you have a point.

Fact is, cold oil not under pressure doesn't exactly flow through a filter at the speed of heat.

__________________
When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

I'd change the little o rings Rocky mentions. After that, if the rattling persists, I'd suspect the oil pump being worn. If that is the case then a rebuild is in order. I'd just drive it and save my money for a rebuild.

I don't know if it is possible to change the oil pump without doing more to the engine or not. I'd suspect the pump may be changeable just by dropping the small oil pan.

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

If desired, before installing the new oil filter, you can pre-soak it in fresh oil,
by placing it in a clean container (metal coffee or juice can) and pouring in enough fresh oil.


This may not be the cause of the startup noise reported by the OP,
but one more thing to consider...the return flow pipe (shaft of the oil canister cover) can get blocked by dirty oil.

When I change the oil, I change the return flow pipe o-rings.
I also flush the return flow pipe with brake cleaner.

Doing both assures finely filtered oil from the bypass section of the oil filter can actually make it back to the oil pan.

W126 FSM 18-005 pdf

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78 W116 300SD 'Desert Rose' new as of 01/26/2014
79 W116 300SD 'Stormcloud' RIP 04/11/2022

I don't normally fill the filter cannister, but seems prudent. Maybe I did a few times. I would if I heard the valve-train clattering on startup, but maybe you hear such because you worry more. For sure, run your hands all under the cannister cover to insure you didn't clamp down on a vacuum tube. I did that once and you wouldn't believe how fast oil pours out. My oil filters usually have a single large O-ring and several copper washers I don't know where to use, so I put in my Harbor Freight kit. I save the old O-rings when not too flattened and recall using one somewhere. Occasionally, I change the little O-rings on the cover shaft w/ ones from my Harbor Freight kits (using Viton when one fits).

Next time, unplug the glow-plug relay so it won't fire and crank until you see oil pressure on the gage. That will spray raw fuel into the cylinders, which you might worry about, but diesel is a fairly good lubricant (why diesel blocks last so long). In summary, you are doing good and your engine should last a long time. Worry more about the things that might kill it, like that vacuum pump. If it starts making noise, be ready with new bearings (cheap) and a rebuild kit.

__________________
1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

I replaced the little o rings last oil change.. perhaps I used the wrong sizes, I just grabbed what i had on hand out a cheap parts store kit.

a rebuild of the pump or the whole motor?

I feel that if the pump were actually worn out it would take a long time to build pressure on a cold start.. no?

Remember that the oil pump has to move ~1 liter of oil into the filter before it's going to circulate to the rest of the engine. At idle, the pump doesn't move a whole lot of oil, so it takes 10-15 seconds before the canister is full and oil gets pushed out to the rest of the engine. When you're waiting for it, it seems like it's taking forever!

As suggested above, it may be a good idea to tie down the stop lever and crank on the starter until oil pressure builds. You could have the idle speed set too high and the noise you're hearing is due to heating of moving parts. Just a thought...

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

The oil pump can be changed easily by dropping the lower oil pan; however, they don't fail often. I'd check a main bearing for excessive clearance by using plastigage if taking the lower pan down.

What brand oil filter, any changes there?

Replace the o-rings as mentioned with the exact ones and check the tube that the o-rings attach to for blockage. The tube has a passage in it that can get blocked.

What is the hot oil pressure at idle? 1.75? Or is the 1.75 hot above idle?

Good luck and keep us posted!!!

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer

Just curious: what brand of oil filter are you using? Have you considered using another brand? The ones I have used are Mann and STP.

Dkr.