MCF

Started getting Low Coolant warning a couple days ago. Checked today and coolant is low. Any anti-freeze sufficient (in Houston) or should I just top it off with water? Also, anyone else experience this? Only way coolant could get low would be a leak, correct? Thanks!!

Live Oak

. . . or an engine gasket --- maybe you are burning coolant now??

MCF

Also. I can see the fluid in the reservoir but it is low, below the halfway point in the reservoir. I can't even tell where the full point is based on the manual schematic. Been reading and have seen people are saying just use water to top it off. Thought??

CEB

Depends on how low. Adding a cup or so of distilled water won't do any harm but much more than that and you'll need to mix with the appropriate anti-freeze.

Anti-freeze not only protects against freezing but also increases the boiling point.

Normally, if all is well, you'll see the "low coolant" at the beginning of winter but it is unusual to see it during the hot months.

Dealers often aren't careful when the do the new car prep to check for appropriate levels so it could have been low and a bit more evaporated to push it over the edge.

Add distilled water and keep an eye on it - checking it always at the same engine temps. If it drops again then you need to get it checked.

mleskovar

Despite being a 'closed' system coolant occasionally needs topping. Some cast alloys can be porous and with all alloy engines topping seems to be needed more frequently....but changing/flushing less frequently (to lifetime) because of no contamination.

CEB

Not sure what you find odd. Coolant evaporates and some will leak, but the loss will virtually be imperceptible.

If you need to add coolant more than once a year then you have a problem. It is impossible to tell in the OP's case because he has no baseline - he can't say "I checked it last month (week, year, whatever) and it was fine.

The only car I've ever owned that drank coolant was my mid '80's Rover 3500 VdP - virually identical in appearance to the car below (but mine was LHD). One had to top off coolant at almost each gas-up.

mleskovar

The graphic means the same as +1....not "odd". Where does evaporated coolant go in a closed system? It should condense back into liquid.

CEB

Not sure what I was thinking. I read that as "weird", not "werd"

Perhaps "some coolant loss" would have been more appropriate than "evaporate" but we're both saying the same thing - top it off and keep an eye on it.

Arrie

The cooling system is a "closed" system but it really is not. If it was you would not have the expansion ganister under the hood where you can see the coolant level or should see, at least.

Coolant can be lost due to evaporation/expansion under extremely hot conditions when the coolant in the engine expands under the heat and runs thru the pressure valve built in the radiator cap in the expansion ganister. This coolant can be so hot it boils when it gets in the ganister under normal pressure and vents thru the drain in the ganister. If lots of the coolant enters the ganister it can just push some out if the ganister is full too.

When the temperature gets lower again the cooling system sucks the coolant back in the radiator and the level in the expansion ganister gets lower. When it does this cycle a few times you can get to the low coolant condition..

Above does not mean there is no problem with the cooling system. You need to re-fill it and I would go to a dealer and get MB approved coolant. A gallon of it cannot be that much and if you feel like it any good quality coolant from any car parts store will do it. Just tab water will work fine too for some amount. I don't know why some valued members talk about distilled water.... A cooling system is not a battery... But don't replace the coolant with water too much as you will lose corrosion protection.

CEB

Right. Buy the coolant from the dealer.

As far as distilled water is concerned, a couple of cups of tap water won't hurt anything but for larger amounts I'd always go with distilled water.

Depending on where you live, that tap water can have lots of minerals and - just like bad tap water can corrode and junk up the water lines in your house or give you kidney stones, so can those same minerals junk up your cooling system.

The coolant in your system is "lifetime" so whatever water you pour in there will stay in there quite a while. When it comes time to flush the system I would flush with tap water to get the old coolant out and then flush with distilled water to get as much of the tap water out as possible - then add MB antifeeze and distilled water.

MCF

Thanks guys. I am going to swing by the dealer in the morning. I talked to advisor and he said they seem this quite often with the W212 in Houston. Hopefully they will just give me a complimentary 'top off' and I will be on my way. I figure with a $60K car it is worth the 3 minute drive to the dealer and have it on record in case there is a leak or something.

hyperion667

dang MCF, you're had a slightly frustrating car eh?

good luck man

MCF

I wouldn't say that..in 3 years of ownership the only real problem was a rattle that turned out to be a suspension component that took many visits to the dealer for them to isolate. Only other issue was a 'whistle' due to cabin filter not being seated correctly. Now this minor issue. Other than the first rattle issue it has been pretty trouble free.

BTW, I just want to bite her a$$!!

hyperion667

CEB

You know, your sig line is making MBWorld NWS - not that I'm complaining...

Arrie

Also check the radiator for coolant level. You have some coolant in the reservoir but so did I with one car I had when the engine overheated and the radiator was empty. Took almost two gallons to fill it up.

Some internal engine problems can cause the coolant to leak inside the engine and be burned never dripping under the car and at the same time the system pressure keeps the coolant from the reservoir from flowing in the system.

Do you have any brownish milky liquid in the reservoir or is it just clean coolant?

hyperion667

first off, the guys at work should be working
and second, if your wife sees that and gets jealous......well, she should be because that is what it's all about......the girl is so fine and has such a great body!

MCF

Dealer fixed it. No wait. A whopping cup of water out of a normal water jug. Says if the warning comes back to bring it in but advisor seriously doubts their is a leak. As long as it goes another 3 years without a low level I'm not concerned.