C-63AMG

Hey guys,

I don't think it's anything major but wanted to confirm.

Twice in the last 12,000kms I've gotten to scares when I woke up.

They were both on cold start:

As I switch the engine on, I get a engine code saying coolant level low, refer to owner's manual.

I checked the oil and I checked the water. No water in oil, no oil in water. I topped it up by like 100 - 150ml and then went on my way. All was fine. I did an OBD check and there was no errors or no faults being showed. That went well and I was relieved.

Then around 6000 - 7000kms later, two days ago, I get the same message. It says 'Coolant Level Low - Refer to Owner's Manual'. I checked oil, checked water. All is fine. Didn't check OBD. Again was short by 100ml.

Is it possible I am just using 100ml of water over 6000kms or so? I wouldn't know if there's a leak at this amount of water being used. It must be a drop a day or so.

How can I rule out the headbolt issue? It doesn't sound it to me? Temps in Dubai are very high and I drive it like it's stollen and my last day on earth.

Help Please!

johnnyblaze

check your windshield fluid level. I kept getting that message when my washer fluid was really low, freaked me out too, took it to Benzworks and Serge had a good laugh at me. I havent had the message since.

Point2Point

How did you confirm that there was no water/coolant in your oil. Did you send your oil out for analysis?

C-63AMG

Thanks JohnnyBlaze, I hope it's nothing.

Point2Point, as I am sure you're very well aware, oil and water do not mix. I drained the oil and looked at the drained oil. There was no water in it.

johnnyblaze

to clarify what I said, having low washer fluid caused the low coolant message on my car. I once I topped off the washer fluid all was good again.

C-63AMG

No buddy, I know what you said. Thanks man. I really hope that's it.

But I find it really bizarre that it would say coolant level low, refer to owner's manual. Why not just say top up washer fluid etc. Why would they scare people like that. Maybe that's what it was. I really hope so

Thanks buddy

CarHopper

My guess would just be something along the lines of what you stated last... Being that you just have a very small leak somewhere.

I would at least do what I could to rule that possibility out now that you seem confident that the oil/coolant are mixing.

Just my 2 cents

Merc63

Don't know if you know, but water boils off at 100C when you're driving the car any water in the oil will be boiled off.

That's definitely not a good way to check.

Take it to the dealer and have them pressure test the system. If there is a leak, it will detect it.

jvanbrecht

Water may boil off at 100C, but coolant does not. Also, the oil system is a pressurized system, whether or not the water changes phases from liquid to vapor is irrelevant, as the vapor cannot escape, and will return to a liquid as the car cools down.. unless you have a leak, in which case then it might..

jvanbrecht

Also, water can exceed 100'C very easily without boiling, its called super heating, and very dangerous as if you break the surface tension, it can explode and burn the crap out of you.. However, this is not possible with water that has impurities.

Merc63

Wrong


The oil system is not completely pressurized. There is a valve to the intake manifold where crank case pressure escapes.

He's looking for water visually in his oil won't work. Coolant has water in it.

Where do you think condensation in the block goes?? Just gathers in the block and makes a swimming pool?

jvanbrecht

Okay, I stand corrected on the pressure issue. As for looking for water, while it may have dissipated, the glycol part of the coolant would remain, and most likely separate from the oil. There would be telltale signs of contaminated oil

C-63AMG

Thanks guys - the first OBD showed no signs of anything.

If I did have the head bolt issue and it started when I lost some small amount of coolant 10,000kms ago, isn't it likely I would have had issues since then considering how hard I drive it? The only other thing is the same warning message 10,000kms later and just topped up by 100mls or so.

It definitely could be the windscreen washer fluid and don't want to rule that out but I'd still like to rule out the headbolt issue. Thanks

Roswell

U should be fine Sam, topping up 100ml every 10k km is not so bad. I doubt it's the headbolts as u would get limp mode pretty quickly once it fails.

Jons95c36amg

I have a 09 C63 and the coolant level stayed full for the last 4years. I have 28k miles. I open it up many times too.

Mort

If you send an oil sample in for analysis that will tell you if there is a high level of water/glycol in the oil. Just ask if the sample is tested for coolant and how they test for it.

Merc63

You shouldn't be loosing any coolant. It's a sealed system.

andrew c230k

How have you determined that your only 100ml of coolant short?

Sounds to me like your not topping it up enough... 100ml wouldn't make much difference in the tank especially if it low and your on a hill etc. The coolant is supposed to be at the level of the tank where the clear top meets the bottom black plastic. If you look inside there is a sensor with two metal rods it could be faulty I doubt it but you never know.

If your coolant is mixing with the oil normally if you open the oil filler on most cars you will see a whiteish light brown foam... at least in other cars that's the case because the Mercedes filler is on the valve cover it might not be noticeable.

Whats your engine temp like when your pushing the car hard?

motoman

Per Mort contact Blackstone for an oil evaluation. Why guess. Although most say head bolt symptom is sudden, it may not be. Perhaps some weeping first.

C-63AMG

Thanks guys, I live out in Dubai so not sure where I can do the oil analysis out here. Re the 100-150ml, I saw the coolant tank and saw it was just ever so slightly below the level line so just topped it up by that. It's fine and I never had the message after topping it up the first time for more than 6000kms or so and then I topped it up again now somedays back and no more message came up.

Temp wise, even when pushing it, I generally run at between 96 and 98 degrees. Thanks

Merc63

Head bolts are torque to yeild.

They could getting more stress than they are able to handle and stretch more. You would have a consistent leak over time.

morganb

I had to top up my Radiator once between services and then had the sudden failure. Prevously and since repair have not had to top up.