Distressing Fallout From an Oil Change

[Jehu]

on August 17 this year I brought my e34 540 to a location run by a large regional Tire and Auto center for an oil change.

I brought two five liter jugs of Lubro Moly 10w30 oil and a filter.

As I was a bit rushed for work I failed to get the left over oil .. with the engine requiring 7.5 liters I would be able to see how much was added.. I forgot about this and headed off.

Yesterday when checking headlight wires after seeing a "Low Beam" message with the engine idling I heard a distressing noise. It was deeper heavier metal rapping noise.

I checked the dipstick expecting to see low oil and saw it was filled completely covering the entire plastic end of the Dipstick.

So as in the past few change intervals I have had the "Engine Oil Low" warning appear after around 5,000 miles I guess there could have been over a quart in excess of the capacity added at that shop .

I returned today to have them drain off the excess which they did .. I ran it for them a but the only tapping noise I heard sounded like it might have been a sticking Lifter being tapped by a Cam Lobe ... but that was not regularly repeatable.

The oil was then at 1/2 between the two notches right in the middle.

I drove it down the highway holding it at just above 3k RPM for a few minutes to get oil circulation..

Shortly after exiting the highway I approached a stop and the engine was shaking, running very rough, and I heard metal like slapping..

I drove it a few miles more to a gas station and checked the dipstick.

It was down to the bottom notch.. I added oil filling it to the top notch covering the bottom two segments..

I d rove it then a few more miles and when I stopped it idled smoothly with no discernible unusual noises .. This has remained the case for the rest of the night driving about 70 more miles and when I parked it it still ran smoothly ..


WHAT HAPPENED?

I thought back to when this shop drained out some oil.. As it was hot they unscrewed the plug nearly to the point of removal allowing oil to drip out.

They did not open the Filter Housing .. Did leaving that sealed create an air pocket in the oil system which left the engine after the first highway run starved and the chugging , rough idle was induced by friction impeding the smooth movement of internal metal parts like pistons rubbing on cylinder walls and bearings grinding ? I thought the crank vent system would prevent that kind of thing from happening but knowing these have two oil pans I don't know how they interact.

I have been adding Molybdenum additive every change for the past 70,k miles and this change was the product which had the Moly in it already.

[bimmer nut]

Dang, sorry to hear about this. Don't think I can help, but I will wish you good luck so that hopefully everything remains fine. They are tough cars. Thanks for sharing. I'm sure someone will chime in with some insight.

[Jehu]

Dang, sorry to hear about this. Don't think I can help, but I will wish you good luck so that hopefully everything remains fine. They are tough cars. Thanks for sharing. I'm sure someone will chime in with some insight.

Thanks Ed


I was pretty freaked out at first realizing I'd driven almost 3 k miles with over a quart or liter too much oil... then to think after draining some out and feeling I may have been lucky to have this second weird episode of rough running and have to freak out all over again wondering how much damage may have occured from that I am ready for the rubber room tonight...

[632 Regal]

Our cars really only have 1 oil pan. Leaving the filter housing closed shouldn't cause any long term affects. Even if it did get filled with air that would have been removed right after you started it, same goes with an air pocket. I did the over fill thing accidentally and the only thing I noticed was a loss of power, drained the extra and back to normal. Sometimes that air can enter the lifters and take a little while to get filled back up, pretty much normal.

The only thing I can think of off the top of my head is the oil pump. Did you ever go in there and check the pump bolts? When I checked mine they were all loose and 2 were in the pan. If the pump is loose it could possibly be cavitating with air but it shouldn't when over filled (not positive). Same with being overfilled if it is being whipped by the crank it could be causing air to mix with the oil. I know nothing about the oil you are using or how it would react to a situation like that.

I have no idea about the heavy noise coming and going.

[Jehu]

Well I did have a shop replace the lower pan gasket about a year or so ago and they did deal with the pump bolts then... I drove it pretty hard today putting about three hundred miles on it and it didn't repeat any of the scary behavior... I did go and get a new filter and changed the oil just to be as much on the safe side as I could in case any metal was separated during that rough episode..

Only thing I thought I noticed was slightly poorer fuel economy on the OBC but it was extremely humid like 100% aka torrential downpours.. very low pressure and wet air.. we'll see how things go when the air dries out and cools down.. Hoping for the best but starting to keep an eye open for a stray low mileage M60B40
Our cars really only have 1 oil pan. Leaving the filter housing closed shouldn't cause any long term affects. Even if it did get filled with air that would have been removed right after you started it, same goes with an air pocket. I did the over fill thing accidentally and the only thing I noticed was a loss of power, drained the extra and back to normal. Sometimes that air can enter the lifters and take a little while to get filled back up, pretty much normal.

The only thing I can think of off the top of my head is the oil pump. Did you ever go in there and check the pump bolts? When I checked mine they were all loose and 2 were in the pan. If the pump is loose it could possibly be cavitating with air but it shouldn't when over filled (not positive). Same with being overfilled if it is being whipped by the crank it could be causing air to mix with the oil. I know nothing about the oil you are using or how it would react to a situation like that.

I have no idea about the heavy noise coming and going.

[632 Regal]

Only thing I thought I noticed was slightly poorer fuel economy on the OBC but it was extremely humid like 100% aka torrential downpours.. very low pressure and wet air.. we'll see how things go when the air dries out and cools down.. Hoping for the best but starting to keep an eye open for a stray low mileage M60B40

Overfilled oil will cause worse mileage for sure. On my 530 after the oil light goes on and about another quart lower it would gain probably 20 extra HP. Not sure how much windage go on in these engines but there must be a lot for it to have such drastic effects.

[Bill R.]

If it was overfilled 2.5 liters then its very likely that the crankshaft was contacting the oil and whipping it up like a blender. Making the oil into foam filled with air. This foam won't lubricate the bearings and won't keep the hydraulic valve elements pumped up so the lifters collapse and rattle. This would be consistent with the roughrunning. If they drained enough oil out that it no longer had the crank hitting it, then you went and drove it with this aerated oil still as the bubbles left the oil while cruising the level would drop like you saw. If you've ever seen power steering fluid get aerated from a leak you'd know what i mean. The foam settles down fairly quick within a few minutes or so.

[Jehu]

Thanks for chipping in Bill

Before discovering the overfilling I experienced nothing out of the ordinary in the running of the engine.. ran same as it had until I started to notice that slight irregular low frequency rap after driving close to 3k miles.

I had another one of these similarly overfilled and drove it about 300 miles.. the following morning I started it and found large amounts of smoke from the exhaust.. I let it sit for a day and the following day that smoke was gone so I concluded the frothing you describe had allowed oil to be sucked up viz the crank vent and drawn into the Intake manifold where it dripped overnight onto the valves and burned off when I started it the next day..

I did not experience that with this episode .

The rough running after the drain off stopped after adding more oil.. The level appeared mid section on the dipstick after draining but when I stopped a few miles after it started running roughly the level was down to the bottom notch. That is still as I understand it not too low to normally feed the engines oil requirements so I wondered if opening the drain plug without opening the Filter Housing created an air pocket which then resulted in a period of oil starvation... I have to think though that since the crank case is not strictly speaking in a vacuum since the Crank Vent system opens to the intake and the oil's weight would seem to be enough to defeat a slight vacuum I was unsure... I did not find any electronic connectors loose such as the MAF plug to account for that chugging..

Anyway I am still able to hear the same fairly deep occasional rapping seemingly from just about the line where the head meets the block not from up inside the head but I can't really be completely sure about it due to the over all noise while running, poor hearing and the irregular lack of clear pattern not hearing anything like it anywhere above idle though..

No oil leaks have developed from over pressurization and fuel economy seems about the same as before ..




If it was overfilled 2.5 liters then its very likely that the crankshaft was contacting the oil and whipping it up like a blender. Making the oil into foam filled with air. This foam won't lubricate the bearings and won't keep the hydraulic valve elements pumped up so the lifters collapse and rattle. This would be consistent with the roughrunning. If they drained enough oil out that it no longer had the crank hitting it, then you went and drove it with this aerated oil still as the bubbles left the oil while cruising the level would drop like you saw. If you've ever seen power steering fluid get aerated from a leak you'd know what i mean. The foam settles down fairly quick within a few minutes or so.