How much fuel in the oil is OK? - Page 2

gobuffs · 10th April 2006, 00:43

Quote:

Originally Posted by fast4door

when the lights go off on the tachometer it is at operating temp. which doesn't take that long to acheive.. so how is that a different issue ?? what you start the car for a minute and call that a trip ?? you might as well walk then....

When the lights on the tach all go off the COOLANT is at operating temp but the oil isn't. The oil temp is the important part of the equation, not the coolant temp. I am actually amazed at how quickly both fluids come up to temp on my E39. My E30 M3 the oil takes a good 10-15 minutes of driving to get it up to temp.

I am jsut telling you like it is, not the way you want it to be. Short duty cycles where the oil doesn't get up to operating temp is not good for the engine. Why in BMW's infinite wisdom did they choose to make the warm up lights on the tach correspond with colant temp and not oil temp is beyond me. The owner's manual of older BMWs stated this clearly. I can't remember what the E39 owner's manual states.

BKH · 10th April 2006, 01:01

Quote:

Originally Posted by gobuffs

When the lights on the tach all go off the COOLANT is at operating temp but the oil isn't. The oil temp is the important part of the equation, not the coolant temp.

That's exactly right, and it does take some time for water and fuel to evaporate out of the oil, probably quite a bit longer than one might think.

ard · 10th April 2006, 01:02

Quote:

Originally Posted by gobuffs

When the lights on the tach all go off the COOLANT is at operating temp but the oil isn't. The oil temp is the important part of the equation, not the coolant temp. I am actually amazed at how quickly both fluids come up to temp on my E39. My E30 M3 the oil takes a good 10-15 minutes of driving to get it up to temp.

I am jsut telling you like it is, not the way you want it to be. Short duty cycles where the oil doesn't get up to operating temp is not good for the engine. Why in BMW's infinite wisdom did they choose to make the warm up lights on the tach correspond with colant temp and not oil temp is beyond me. The owner's manual of older BMWs stated this clearly. I can't remember what the E39 owner's manual states.

Actually I've monitored oil temp (OELTEMP) on the 'hidden' IKE display and correlated it to the tach lights.

First orange light is off at 41C, second at 51C, last at 61C... so the engine is NOT at what I would consider operating temp when the last light is off. I usually wait for 70-75C before getting much over 5k

Forgetting what the manual says, if there is fuel in the oil and it is not getting hot, it will not evaporate...

Thanks for the tip on the breather valves. (Doesn't this also lead to oil in the plenum? I should check...)

A

jaj · 11th April 2006, 08:19

The S62 has a large and efficient oil-to-water heat exchanger that acts as an oil-cooler when running hard. When warming the engine, it heats the oil up nearly as quickly as the water heats up. Otherwise the S62, with its aluminum block and large pan would a very long time to warm the oil.

I'm not sure of all of the causes for oil in the plenum - when my 2001 had it, it was because of a broken o-ring on a VANOS component. That flooded the breathers and then backed up into the plenum which overflowed into the air filters. Others have had the problem for other reasons, but I am not sure what that was about. I know about mine because the dealer showed me.

Maybe heavy blow-by could cause oil in the plenum, but I am not sure why that would actually happen if something else wasn't wrong.

Cheers
JJ

mottati · 11th April 2006, 19:06

I had an increase in manganese as well, but was told that could be caused by changes in our california gas recently. No other changes in my fuel, flashpoint or insolubles.
Adam, i'd try the basics first, on your dime most likely. Get a fresh set of plugs in the car and some of the vw mafs, you'll be surprised how much better it will run. You can do this yourself for $100 or so.
Mike