500SEC COOLANT PROBLEM

[mercedes dentist]

The joys of owning a sec, suddenly loosing coolant, I check levels weekly, a few days ago it was low, I topped up to level and drove 18 miles and then 18 back ( went to my service specialist, John Haynes) on another matter, It took half a litre to top up again, no sign of leaks on the garage floor, temp. steady, no smoke, looked in oil filler cap, all ok, please help and advise, my pension is taking a battering this year, but that's life as they say.

 

[LostKiwi]

Get some UV dye (kits on eBay). Add to coolant and look for tell tale using the torch in the kit.

 

[mercedes dentist]

Get some UV dye (kits on eBay). Add to coolant and look for tell tale using the torch in the kit.

Get some UV dye (kits on eBay). Add to coolant and look for tell tale using the torch in the kit.

already done that, no signs.

 

[LostKiwi]

If it's not leaking the only other place it can go is out the exhaust..

 

[Dean Fletcher]

I had this once turned out to be the water pump. I was putting in about a litre a week.

 

[star]

If it's not leaking the only other place it can go is out the exhaust..

Could be heater matrix but very rare. More likely rad or water pump. Did have a header tank split underneath.

 

[Jim2]

Does this model have the fuel filter which is water heated ?

 

[star]

Does this model have the fuel filter which is water heated ?

No, never seen one.

 

[mercedes dentist]

No, never seen one.

A little water from the tailpipes after starting cold but no more, could the coolant be drawn in to the pipe that runs in to the wing, I understand a plastic container is in the wing, if this is so what happens to that coolant?. no sign of leakage around the pump or flexible pipes, yesterday I ran the car in the drive for 30 minutes, no overheating and no loss, I am old and bewildered. I was told sometime ag that when mixing coolant boiled water was best.

 

[Jim2]

No, never seen one.

Thanks Star...I guess that the heated filter is only in the OM651 Engine, as in the w212 merc's?