Fishcakes87

Does anybody have any idea what this milky liquid could be? In small parts there’s patches of pink/red so I’m not sure if it has turned milky or if it is mixing with another leak!?


The puddle is located at the front/centre of the car and biases the driver’s side (U.K.)

TIA,

Lee

user33

Likely coolant. If you check in the engine-bay area, you may find evidence of the leakage. Assuming your reservoir cap isn't loose, suspect hoses, clamps, etc. It would have been good to indicate the mileage on the vehicle.

Fishcakes87

Yes good point - It’s covered 44,000 miles.

No evidence of a leak under the bonnet but can’t see any leaking when looking underneath either. Coolant is baffling, never knew it would do that upon contact with water?

It’s now booked in to be checked over.
additionally,
When checking the oil level using the dipstick, it appears that the oil is well above the ‘max’ line. Car has been stood around an hour & a half so assuming the oil has fully drained into the sump.
It’s hard to read, but I’m convinced it’s been overfilled - No warnings on the dash however.

MatthewJ

When you wiped the dipstick was it that milky color as well?
when was the last oil change?
That is a wide array of drops/puddling so its hard to tell where on the motor its coming from unless you pull the windtray and inspect.
Both coolant tanks show full?

RichardCranium3

If coolant, you'd typically get a sweet, pancake syrup smell from the puddle, or while driving.

user33

So, on a Canadian-delivered car, would that be "a sweet, maple-syrup smell?" #;-))
(sorry, couldn't resist)

Fishcakes87

UPDATE: Took the car in to the garage, they said they pressure tested the coolant system and it was fine.

the car hadn’t leaked since so I was a bit miffed as to where this mystery liquid has come from.

Today I jacked it up at home to see where the oil drain plug was located (I always change my own oil/filter) and while I was looking I saw very small deposits of pink coolant scattered around the lower engine bay/pipe work!

I started the car and saw no drips, coolant levels look OK - but I did notice something odd, the smaller reservoir contained the exact same pink liquid that I saw scattered around the place, the larger reservoir to the left (black) contained what looked like murky water. (picture below)

Should that not be coolant also?

Another question going around my head… is there a pressure relief valve somewhere on the coolant system that might have caused this one-time spillage? I’ve never seen the oil/engine temps go above 100 yet.

MatthewJ

Both of the left reservoirs have the same pink coolant. The black top one is engine coolant and the proper fill level is at the top of the plastic "T" or cross down inside of it. (engine cold).
the smaller and clear reservoir is for the liquid to air intercooler. Has the same level indicator inside of it.
Both should be a nice pink and translucent color, not what you have pictured in the syringe.
Contamination in the black reservoir would be most concerning as this would indicate a head gasket failure. I have not heard of this happening yet on any M276.
Was there work done on the cooling system? Could someone have used incorrect fluid to top it off? Any issues with the car overheating at any point in its life?

Fishcakes87

For as long as I’ve had it, it has never overheated, it hasn’t even got close.

I haven’t yet seen the temps go above 100C

-No white smoke from the exhaust
-I performed an oil change and the oil coming out was in quite a good condition.
-No loss of power that I can tell either so I don’t think it’s the HG.

Only mystery is that the ‘coolant’ seems to be water, which to be fair seems to be keeping the temps in check anyway. And the levels were OK too.

I’ll get that system flushed and re-filled and look for any changes to the fluid afterward.

Fishcakes87

LATE UPDATE;

I was head down a couple of weeks ago looking puzzled and suddenly something weird caught my eye - The hose coming from the small reservoir had somehow become un-clipped from a larger one, managing to get trapped in between the engine block and one of the pulley wheels!!

I pulled the hose out and there was a split about an inch long and only dripped when the engine stopped.

Took it to the local dealer and all in including labour cost me £216 to replace it (about 1.5hrs work, part was around £65)

However - Once replaced obviously the leak has ceased, but the reservoir level had dropped after the work (I thought they would have topped it up after losing some during the replacement?)

when I run the car everything seems fine temperature-wise, but when I open the bonnet, the main reservoir is hot, and the one with the replaced hose is cold. Shouldn’t the coolant in there be fairly hot too seeing as the gearbox temp is around 89 degrees??