Top of the radiator 2015 ML350
Just found out that my radiator leaks. Any recommendations for repairs are appreciated

Thank you

 

I have the same issue - same side but it doesn't leak enough yet to be a problem for me. I would not recommend any "stop leak" additives as they can collect in other areas (besides your radiator),

Unless you have a local shop that rebuilds them, you can pick up an off-brand for $250-300 USD online. The Mercedes brand ones are around $600

 

Replace the rad.

 

Super common weak point on radiators used in all W166 (ML/GLE) and X166 (GL/GLS) SUVs. Often fails at well under 10 years/100,000 miles. Might be a matter of when and not if it will fail... Here's a thread on the X166 forum discussing it and a bodge-style repair involving epoxy radiator plastic weld/patch. The safest way to address this longer term (and what all shops will tell you) is to just replace the radiator. On a W166 ML 350, it's a far easier job than on other chassis (book time is definitely inflated...). Shop around, and you might be able to find a new Genuine Mercedes radiator for well under $500 (the more competitive dealership parts depts. in my part of the U.S. list them for less than $450). A Mahle Behr equivalent to that radiator can be found for closer to $250. A Denso aftermarket compatible radiator runs for less than $200. I don't have direct experience with all of these radiators myself, since the Benz shops I deal with only use Genuine Mercedes for these W166/X166 models. Perhaps others can provide their experiences and comparisons with the aftermarket radiators, for those interested?

One last word of advice: I was talking to my mechanic the other week about preventative maintenance on the cooling system. Specifically, I was exploring coming up with a list of components to replace preemptively when getting my serpentine drive belt, pulleys, tensioner, thermostat, coolant expansion tank/reservoir, and coolant flush service done the next time I see them (100,000 mile service). The thermostat housing is plastic, which gets brittle and eventually also leaks...as well as the fitting my mechanic describes in (yes, he's the mechanic with whom I've had these sorts of discussions over the years...and, now, he has a social media presence). I'm also looking into getting the plastic fittings by the firewall going to the heater core replaced before they crack and spray coolant, which they will eventually, in addition to several other hoses and fittings... You might want to consider this, since these are very common failures (much worse on the turbo-charged models).

 

Common failure. Broken attachment lug. Replace the radiator.

 

It's a two-person job to get everything aligned again. I would recommend paying a competent independent to replace. As far as OE vs aftermarket, it's clear the OE is crap so I would recommend going with another manufacturer. Mine recently failed and started leaking too. It was a PIA job.

 

thank you for the update.