Drop of coolant

[erickh]

Last Nov 2017, there was a leak where white powder was found around the cap.
Replaced the cap and topped up the coolant.
Last week coolant lights came on again, dropped by about 1cm.

3 months ago, my turbo pipe did split and I had to drive down for about 45 mins in limp mode on the M3.

I was wondering they are both related? Eg. engine heating up, drying the coolant up?

Also I shine from the top, can't see anything obvious.
No white residue anywhere.

Any advice?

 

[LostKiwi]

Last Nov 2017, there was a leak where white powder was found around the cap.
Replaced the cap and topped up the coolant.
Last week coolant lights came on again, dropped by about 1cm.

3 months ago, my turbo pipe did split and I had to drive down for about 45 mins in limp mode on the M3.

I was wondering they are both related? Eg. engine heating up, drying the coolant up?

Also I shine from the top, can't see anything obvious.
No white residue anywhere.

Any advice?

Unrelated.

 

[Jim2]

About one week ago, I put some leak finder into the reservoir on mine ( about 50% of the supplied bottle) and it promptly changed the antifreeze from blue to green !!! ( with hind sight, maybe I should have done this before did the change and flush.... ) So far I have driven about 100 mls, but not the slightest sign of any fluorescent anti freeze staining that I can see looking at it from the top. I will have to put it up on a lift and take down some of the mud shields, and see if it shows anything from underneath. It's not leaking much, but even a little leak bothers me ( at least until I find out where it leaking from, and more to the point, where it's going visions of it appearing in the ATF haunt me.....I have got some water miscible test strips to check out the atf. If you find out where yours is leaking from Erikh, would be good if you can share it.

 

[erickh]

About one week ago, I put some leak finder into the reservoir on mine ( about 50% of the supplied bottle) and it promptly changed the antifreeze from blue to green !!! ( with hind sight, maybe I should have done this before did the change and flush.... ) So far I have driven about 100 mls, but not the slightest sign of any fluorescent anti freeze staining that I can see looking at it from the top. I will have to put it up on a lift and take down some of the mud shields, and see if it shows anything from underneath. It's not leaking much, but even a little leak bothers me ( at least until I find out where it leaking from, and more to the point, where it's going visions of it appearing in the ATF haunt me.....I have got some water miscible test strips to check out the atf. If you find out where yours is leaking from Erikh, would be good if you can share it.

Will do. Taking down to get it checked next week when my car is in for the MOT.

How fast yours drop by?

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[Steve@Avantgarde]

You likely have a slow coolant leak from the fuel filter housing which attaches to the side of the cylinder head. It often goes unnoticed as coolant leaks go. Look for dried coolant on top of the inlet manifold.

 

[Jim2]

Will do. Taking down to get it checked next week when my car is in for the MOT.

How fast yours drop by?

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Hi again Erickh, from top-up to the correct level in the reservoir, to the time the low level warning comes on, roughly 3 -4 mths. I changed it recently as I did not want to be diluting the mixture with water, and it can cause complications if you mix different anti-freeze's. So now it has been changed and I know what to top it up with.Ideal of course is to find the leak, and fix it. Steve has made a very good suggestion here on this forum. Check it out for your Merc too.

 

[Jim2]

You likely have a slow coolant leak from the fuel filter housing which attaches to the side of the cylinder head. It often goes unnoticed as coolant leaks go. Look for dried coolant on top of the inlet manifold.

Thanks Steve. I will check that out. So the fuel filter has a water heated element in it?

 

[erickh]

You likely have a slow coolant leak from the fuel filter housing which attaches to the side of the cylinder head. It often goes unnoticed as coolant leaks go. Look for dried coolant on top of the inlet manifold.

I will have a look. Thanks for the tip!

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[erickh]

The garage found a very very small stain on the water pump. However when they pressurised it, the coolant wasn't leaking. Said to keep an eye on the level and go back if it's dropping drastically.

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[Jim2]

Ther

The garage found a very very small stain on the water pump. However when they pressurised it, the coolant wasn't leaking. Said to keep an eye on the level and go back if it's dropping drastically.

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There is a slight water stain on the water pump on my car too, erickh. But even after adding the leak finder to the water, nothing is showing with the ultra violet light. So as soon as I get the chance, I will check out Steve's suggestion re fuel filter housing.

 

[erickh]

Ther

There is a slight water stain on the water pump on my car too, erickh. But even after adding the leak finder to the water, nothing is showing with the ultra violet light. So as soon as I get the chance, I will check out Steve's suggestion re fuel filter housing.

Ah right. I did point out about the fuel filter housing.
But obviously they know better than me. Also nothing came out when the system was pressurised which is the odd bit.

@Jim2 What model is your car?

 

[Steve@Avantgarde]

Thanks Steve. I will check that out. So the fuel filter has a water heated element in it?

The fuel filter housing is also a coolant passage to the thermostat. It bolts to the cylinder head, except its made of plastic, it deforms, and then leaks where the seal to the head is.

 

[Jim2]

Ah right. I did point out about the fuel filter housing.
But obviously they know better than me. Also nothing came out when the system was pressurised which is the odd bit.

@Jim2 What model is your car?

Mine is a 2010 E Class w212, M651.9 engine, 136 HP Blue Tech. erickh. In older Mercs, it was not uncommon for coolant to mix with the trans ATF, via the shared radiator. But I don't think that this happened in newer models. If it was the cause of the coolant loss...would be very problematic...….. So I'm keeping the fingers crossed that its the fuel filter housing.....

 

[erickh]

@Jim2 the issue didn't manifest itself when they pressurised mine. How annoying! I will just keep an eye how quick it drops.

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[erickh]

@Jim2 Do update us please once you have more success finding out yours

 

[Jim2]

@Jim2 the issue didn't manifest itself when they pressurised mine. How annoying! I will just keep an eye how quick it drops.

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Yes it is annoying...if it's just leaking a very small amount "out" of the system, and you keep it topped up, no real problem !!! However, if its leaking "into" something, that's a different kettle of fish entirely...hence my remark about older mercs leaking antifreeze into the trans ATF via the shared cooling radiator.( Google this, for examples )
I regularly check the ATF level, plus I use a water finder tab to check the ATF fluid for water. So far, so good !!! No indication of any water, or a rise in the ATF level. Bear in mind, that the ATF level's can change dramatically, with even a small amount of additional liquid added.
I made a "T" shaped dipstick for checking the level in the coolant reservoir, and cut notch's in it to mark "MIN" and "MAX" levels....now since I have changed the coolant, I'm waiting for the "Low Water" warning to come on. Then I will top it up, taking note of the amount, the date and mileage, and that will give me a reference point to "map" the loss.

 

[erickh]

:-(

I've misread, thinking that we had a similar issue. Hope you will be able to find the culprit soon.

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[erickh]

Any luck @jim?

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[Jim2]

Strange enough erickh...since I drained the old stuff out, flushed it and refilled with the Comma Xtream 48, it does not seem to be leaking as much, bearing in mind that the leak was never a bad leak,,, very minute leakage. But it still bugged me. Since I changed the coolant, ( 2 mths ago ) I have not had to top it up. But this could be due to the fact that I may have overfilled it slightly. I will stay driving it now, and wait until the sensor tells me it need's topping up. In any case, I check all the levels regularly, I have ordered a boroscope, and when I get it, I will check the area around where the heated fuel filter housing attaches to the engine block and try to see if its leaking from there. Seems to be a common leaking point. With a bit of luck, the boroscope will do the job, and I won't have to strip the filter housing + plus some other parts off the check it.