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Oil in water :(

5K views 37 replies 11 participants last post by  M_zver 
#1 ·
Well, i was fettling with my vanos and went to drain some coolant... it had lots of brown sludge in it...

Car is running fine, no codes, no overheating, no smoke from the exhaust and oil is fine...

Car is having the coolant flushed now and a leak down test.

Any chance it could be anything but a head gasket failure?
 
#9 · (Edited)
Hi sailor24,

A new radiator and expansion tank was put in about 3 years ago. I asked for a coolant flush then and even if they didn't flush there should have been a fairly large change in coolant.

A year after that, when the rk heads went on, i also asked for coolant flush. Perhaps they mixed up the types of coolant? Or topped up with Thai tap water? Who knows!

Most of the sludge didn't float, a tiny amount did.

Honestly, I really am hoping that it is old and crappy coolant....
 
#10 ·
It usually takes a long time for it to break down, but if it was the green stuff there are lesser brands that can break down much quicker. I put some cheap stuff in my diesel truck and it only took two years for it to break down. If it was oil then you likely have some transfer the other way. Any signs of moisture in the oil? Usually shows up as white crud on the dipstick or bottom of the oil cap?
 
#13 ·
Um, there's some mistake in what you were told. You say that "the leak down equipment hit the fan and ripped the blades off"....but a leakdown test is done with the engine off, turned by hand with a wrench to each cylinder's top dead center.

It sounds to me like the shop did a compression test, not a leak down test. A compression test is a poor test for bad headgasket, but an ENGINE HOT leak down test is the best test.

The fan hitting the test equipment, whether leak down or compression, is the mechanic's fault. The shop owes you whatever was damaged. But I'd also pin them down, how they had the engine running during a leak down test.

You need to be aware that during the fan hitting something hard enough to break the blades possibly also may have damaged the fan clutch, and possibly even the water pump.

While you'll probably have a hard time convincing a shop to buy a new clutch or water-pump job when the parts aren't obviously broken, you might get the shop to acknowledge responsibility if these items fail in the next couple of months.
 
#14 ·
For reference, copied and pasted from a mechanical forum:

Coolant Changes and Checks

Over the years BMW has changed the replacement interval for coolant from every 2 years to every 4 years. You should replace the coolant according to what your owners manual calls out unless it states that the car has lifetime coolant as some of the latest cars call out. In that case don’t go beyond 4 years on coolant changes and 2 years is even better.

Unless you are meticulous in keeping maintenance records, put a sticker on the radiator showing the date of the last coolant change.

Use BMW coolant mixed 50:50 with distilled water. Tap water contains dissolved oxygen and may contain minerals that will use up the corrosion protection package and shorten the life of the coolant.

Even if you are changing the coolant on schedule it makes sense to periodically check the coolant with test strips and/or do a voltage check. When changing the coolant you must drain all of the coolant using radiator and block drains.

While it is best to top up the cooling system with coolant mix, adding at most a quart of distilled water between changes probably won’t cause any harm. So keep some coolant mix on hand.

From bmwdirtracer:

An electrical charge in your coolant as low as .15 volts destroys aluminum very quickly, and I've seen many cars with twice, even three times, that voltage in their cooling system.

This charge generally occurs because of old coolant which has lost its protection package and begins to swap ions with the aluminum and other metal components, causing the coolant to become an electrolyte, much like a battery, producing its own electrical charge as it eats the aluminum.

Set a good digital multimeter to DC voltage. If it is an auto-ranging type it will start on the lowest scale, but if not set the meter for the lowest voltage scale.

Attach the negative probe to the best ground - ideally, the battery negative post, although the main ground post underhood will do, in a pinch. Ground the positive lead of the multimeter, momentarily, to make sure the meter reads zero.

Then dip the positive probe of the meter into your coolant. If you see a voltage of 0.15 or above, it's time to change your coolant.​

The car makes it possible, but the driver makes it happen.
Jim Levie, Huntsville, AL
NASA & BMWCCA Certified Instructor
NASA MidSouth Spec E30 Series Director
 
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#15 ·
Thanks for clarfying the difference between leak down and compression :)

The shop has already ordered the fan, I'll talk about the water pump/fan clutch with them and bring up exactly why they were doing compression when i asked for leak down.

Thanks again.

Sigh, it was supposed to be a coolant flush and a simple leak down test....
 
#16 ·
When you've paid a good BMW shop to do something, you have paid them to do the job CORRECTLY.. When they screw up (which does happen), they owe you for expense caused by their error. If they acknowledge that, and take responsibility, you've found a good shop. There are still some of those out there.

There will always be a tough call, whether the technician or an old crusty part, is at fault, when something old breaks. But if test equipment got in the way of the fan, yeah, that's my fault, if I'm the tech, doing a compression test. (If I were doing a leak down test, and broke the fan, I'd be a dumb ***. I try to avoid that particular label.)

Is your new coolant blue? If it is not, you need to find a different shop.
 
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#19 · (Edited)
Got my car back, they fixed the broken fan, replaced belts and the damaged pulley. They say they pulled the heat exchanger and pressure tested it; no leaks

After putting new coolant in, the system ran clear initially but then muddied up again.

Could be old gunk that has moved or new gunk being formed.

Anyhow.... I took a sample of coolant and gunk into work. Dropped some of the gunk in water; immiscible. Dropped some in hexane;miscible.

So. It's oil (or at least a non polar liquid less dense than water) and not random old coolant stuff.

Pic from left to right:

sample taken from expansion tank. gunk dropped in distilled water. gunk and hexane.
 
#22 ·
Hi sailor24,

The first picture is the sample I took from the expansion tank. Most of that is the red coloured coolant that got put in this weekend. The shop has it's issues as I'm sure you've read.... It'll be drained and replaced with BMW fluid I have at home this weekend. The top layer is the tan gunk that keeps appearing.

The second photo is distilled water and the gunk added. The gunk just floats on top.

The third photo is the gunk added to hexane and it dissolved immediately. Hexane is non polar and engine oil is essentially non polar. In simple terms, like dissolves like; oil will definitely dissolve in hexane.

Different antifreezes will certainly have different properties, but there is no getting around the fact that water is a polar solvent and the other liquids in antifreeze also tend to be polar.

Cheers
 
#25 ·
Most of the sample in the hexane looks like it is floating. Some has gone to the bottom, but that could be veg oil that is added to some anti freezes as a pump lube. I am no chemist but I thought veg oils separate from the hexane but petros dissolved and needed another step to get out of the hexane. The little I know of it was using it to extract oil from soya beans. Have you ever added water pump conditioner/lube?

If it was me I would use a cleaner/flusher and do a complete flush/clean then drain every drop after I had done several water rinses. With the heater on full. Fill it up with water only and drive for a couple of weeks. I assume it is warm enough now that it does not freeze. In a couple of weeks you will get an idea of what it is and how much. If it is small I would contemplate a block sealer.

The thing is: it does not make sense that you can have oil in the coolant without coolant in the oil. If it is head gasket or internal to the engine. If there is a passage between the two at some point the coolant will have a higher pressure than the oil pressure and flow into the oil.

That said it does look like it could be oil, but I don't see how it mixed so well in your first post.
 
#26 ·
Hi Sailor24,

I have never added any conditioners/lubes. I have never asked any shop to add any, but who knows..

Vegetable oil should dissolve in hexane. The molecules that make up vegetable oil do have polar section but they are mostly non polar. Hence why veggie oil won't mix with water (a polar solvent).

A volatile non polar solvent can be used to extract an oil from something (bean or otherwise!). The oil dissolves into the non polar solvent, then you remove the solvent easily due to it's volatility.

Your plan is exactly my plan; flush several times then watch very carefully. I also don't understand how there can be only oil to coolant and not the other way around.

I'll update in a week or so.

Thanks for everyone's input.
 
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