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Hi guys, I've been trying to Google some info but coming up blank, I've had my 2014 E220 2.1 cdi AMG for a couple of months & been really happy with it but ive noticed a leak from the front end, Its coming from the auto transmission cooler, I took it back to the garage I bought it from & they are sure its coming from the water side rather than the oil side but they said they are having a hard time finding the o ring part number or even the hose for the car, Would anyone have an idea of the o ring size or a part number for the o rings or hose on the water side on the cooler A0995002300 if you are looking from the front of the vehicle its the connection on the left rear of the cooler.
If it's water that's leaking out then that answers your question as to which it is. As for where it's leaking, I can't help you because it looks fine in the pix. O-rings are a problem so I'd bet that over a hose.
If you can't find the exact O-ring then I'd just pull it out and find one local that's close. I'm sure it's metric but O-rings are far from precision so I've never used a metric one on a metric part and I often use a size up or down depending on the situation. In this case it's low pressure so not a big deal and close it good enough. No clue where you live but I'm the US and I don't recall ever seeing metric available except online.
If you don't want to remove it first to find out the size, and nobody pipes up here, then I'd just buy a bunch that are in the general size range. I have hundreds of O-rings on hand for situations like this. I'd say the O-ring is most likely ~.140" thick which is very common. Then I'd eyeball where it goes say it's ~3/4" then buy several around that size. AS568 is the spec for O-rings sizes if you want to google charts online. I'd imagine it's a -115 or so? Eg AS568-115. Or the local hardware store which usually size then by fractions of an inch but you'll figure it out. Just don't buy from Harbor Freight or other misc cheap place because their O-rings suck. Like if you get a pack of 250 or something for $10, you don't want 'em.
Thanks for the advice, After being on the phone to our local Merc parts department & even giving them the part number for the cooler they couldn't help with the o ring or hose as they couldn't see it on their system, No idea how they think the coolant gets into the system, Anyway the mechanic went to a local engineering workshop & managed to get a few around the same size & got one to fit.
What an amazing amount off hassle just to get an o ring but hopefully that's the last time it has to go anywhere near a garage until its in for its next service 👍
A quick update, I got the car back from the garage & was told it has all been sorted, I drove it back to my work & after checking under the bonnet the leak was still their, I told the garage about it & they told me they would try & order a new hose, As its a 120 mile round trip back to the garage I got one of the fitters in my work to give me a hand & we tried several different size o' rings but the leak is still there, The new hose will be delivered to my works address tomorrow but I was just wondering if anyone has had problems with these connectors or is it more likely to be the actual oil cooler that's faulty & needs to be replaced.
Crap. Well, it's hard to say so what I do when in question is clean it all up then fire it up and watch to see where it leaks. Optionally clean it and wrap strips of paper towel around various parts to see which gets wet first.
The hoses would be my next suspect. I assume the mech knows this but you have to clean that puppy out when swapping O-rings because any leftover corrosion, dirt, O-ring bits or whatever can break the seal on the new O-ring. Same for the groove where the O-ring sits, which might be corroded and that caused the leak so a new O-ring over it might stop if for a while, or just slow it down for a while. So if leaks less than before then I'd suspect the O-ring surfaces. If it leaks more than before it could be debris in there or the manhandling of the hose made its leak worse. So many scenarios but on avg that's my opinion.
The hoses I usually do by feel because they break down and get softer, and usually you can feel one spot is extra soft. Some hoses get harder over time and as a result the hose clamp doesn't really do the job anymore and even clamping harder may not help. From the pix it looks like the hose is just fine. With that in mind, are we sure the leak is coming from there? Could it be something else that is "framing" your trans cooler? Happens a lot fyi. Drips and follows a line or surface from elsewhere, or sprays, or the fan blows it. I've even seen where they won't leak until after the car is off because often pressure is highest several minutes after shutting down on a hot day.
So imo, clean it, dry it, fire it up and look for the leak. No leak, let it fully warm up, shut it down at watch.
The cooler itself can leak too, but not sure how often that happens. Never happened to me, never seen it happen that I can recall. The hose and O-rings are pretty much guarantee to leak sooner or later.
05-25-2022, 03:35 PM
