bhamg

I mark my ideal coolant level with a magic-marker dot on the reservoir. The times I check the overnight-cool level in the morning, garaged all night with the hood open, the coolant stays rock-steady on the dot for months. After a 150 mile day on Sunday, I checked the coolant level on Monday and it was low about 3/8". Very strange to see it but I thought I would just drive it normally for a day and see what happened. Well this morning I headed out and within a half-mile the car threw a check engine light and had NO power. I was lucky to be able to limp home and pull into the garage. I mean NO power...could barely rev at all.

I left it in the garage, hood up, took a BMW north and just got back now at 2am (long day). I see the coolant is down further to somewhere between 3/4"-1". That's perhaps 10-12 oz of coolant lost in two days. The garage floor is perfectly clean and there is no fluid leak of any kind under the car. Not looking so good, I'm thinking possibly a head bolt or two. If so, I'm lucky the misfiring happened so close to home and I didn't drive with much coolant in the oil. I'll be gone all day tomorrow but will check to see if there are any additional codes other than the P0300 I saw this morning and report back.

norb

Good luck. Hope it turns out to be nothing.

AMG893

Damn.
Subbed.
Hope it works out

mr747

not good b

Let me know what happens I hope it's all good my friend

itzjonjon69

yes please keep us updated!

Ingenieur

sounds like the symptoms on the TSB

what year and how many miles?

ToXicXxX

Throw some UV tracer dye in your resivour, then after 100-200km, hit your car with a blacklight. Hopefully it's just something like a pinhole leak in a coolant line. You may have a phantom leak (common on BMW's), in which the coolant dribbles out of the corner of the rad where the plastic is formed, and dries instantly while moving due to high speed air passing it. It only leaks when the system is under pressure (hence no garage floor drops).

I serviced a 2012 ML350 Bluetech yesterday that was leaking coolant out of the sensor (the coolant had eroded the plastic away and was dribbling past the contacts), so that may be a possibility for your car.

If your head gaskets are going and the car is burning coolant, you will noticed somewhat thick, sweet smelling white smoke. If you don't see this, your car likely isn't burning coolant.

Merc63

Bhamg you know better than to drive the car home with these conditions.

I have studs and my coolant was low a tiny bit the other month. That warning came on in the dash.

PetroC63

Any white smoke coming from the exhaust?

Girard@ACGautomotive

^
This?

Sorry to hear buddy, hope it all works out in the end.

Let me know if there's anything we can do to help.

Ingenieur

low coolant would not cause a CEL and limp mode
unless it is getting into the cylinders and causing a misfire

I don't think he did anything wrong by driving it, no warnings were present
he noticed it was a bit low but no CEL or low coolant warning
the manual says to just add some

the code is for random/multiple cylinder misfire

the fact that is keeps dropping coupled with the misfires does not bode well
exact symptoms as in the TSB

abcut973

For sure this is alarming. But before drawing quick conclusions make sure every troubleshooting steps are explored. I would definitely look for sources of leakage.
The CEL might be or not related to the low coolant as Ingenieur mentioned. Now if you look at the known cases of headbolt issue most of them were showing low coolant warning on the dash. Not everyone monitor its coolant level. In your case could be a sign of a beginning issue hence no warning yet.
GL

bhamg

Car is an '09 with 45k miles.
Codes are P0300 and 01, 02, and 04.

I put the car up on stands this morning and took a look. Didn't see any evidence of a leak and couldn't smell any tell-tale odors. Everything is on hold until my SA gets back to work next Monday and we can speak.

rjej84

Subd. GL.

bhamg

It happened so fast and I was so close to home that I only looked once to see if I was impeding anyone. No white smoke that I noticed but I was barely above fast idle. I GPS'd it this morning and from when it all happened back to my garage door is about 420 yards. The engine was still essentially cold.

mr747

i had these codes come up the other day and it was my oxy sensors

Changed them out and car was good to go

Maybe your oxy sensors are gone

as far as the coolent issue i have no idea

Ingenieur

Check the oil level
See if is higher than normal
Smell for coolant

In the middle of the expansion tank (transition white/black or normal level) the volume is ~17 oz per inch

I've been measuring mine too
Same spot sitting overnight
I use a caliper from lower lip to liquid
Mine dropped 3 mm or 1/8" in over 6000 miles of sustained highway running
2 oz or so

splinter

Ouch! :(

Good luck on its diagnosis.

PetroC63

Check the oil dipstick. If it looks like a milkshake or it has a sweet smell to it coolant has gotten in.

bhamg

Thanks guys. There is no doubt the coolant went somewhere and based on what Ing posted it would be a minimum of 12 oz over a two day period. I checked the oil. No foam and the oil has a familiar clarity but it smells subtly different now...or is it my imagination? It does looks to have a slightly different (slight reddish hue) color on a paper towel though. Again, could be my imagination.

Ingenieur

did the level rise?
you lost ~ 1/3 to 1/2 qt, it would be noticable on the dipstick (what is the range fill/full? edit: 1.6 qt)
a good portion would go into the oil (the remainder thru the combustion chamber)
assuming headbolt or gasket failure

bhamg

I just pulled one L of oil out of the sump via vacuum extraction, 1/2 of the sample from the bottom, then 1/4 out of the middle and the final 1/4 near the top. I'll try to find an oil analysis lab in SoCal and drive the sample there in addition to saving some to send out to Blackstone if necessary. I'll presumably get to the bottom of whether there's any coolant in the oil.

Ingenieur

Let it sit over night in a clear jug
The taller and narrower the better
The water/coolant will settle on the bottom

CPD SLK

Aww dude, that sucks. Best of luck..can't believe Mercedes hasn't taken care of this...fucing BS. Ask ur dealer to contact MBUSA and try and get this covered. It seems to be a case by case basis is what my service advisor says

bhamg

The local/regional angle didn't work out because it seems anyone offering that service outsources it anyway, but Blackstone will have my sample on Mon.