Autotechnica

Hey guys,

So I've been losing coolant on a steady basis for the past 6 months. Up until now I couldn't see any leaks. I could just smell heavy coolant fumes. Today, low coolant light came on and I saw a trail of coolant behind me as a I pulled away.


Doesn't looks serious I hope. My rad has been replaced with a BEHR about 2 years ago. It looks like it's leaking from the internal clamp/seal. What a pain that Mercedes uses such complex fitments. Why can't I just have a normal radiator neck and clamp. Anyways, any idea if this is a common issue or possibly what parts I need? I think I've replaced the upper rad hose ages ago so I don't recall how to remove it. Anything in particular I should be looking for? Does that metal piece between the hose and rad look seated properly? I just hope the neck isn't cracked.

thanks.

Bry

Gramma_Benz

Hey man, just count your blessings and realize how lucky you are that the leak is there and not your intercooler eating coolant!

Good Luck!

bdougert1220

My 55 was leaking from right underneath the upper rad hose and.when i replaced it it ended up just being a small hair line crack that leaked pretty good and since i had 90k on the original rad it was time for it to be replaced anyway dont want to get my trans fluid contaminated

Autotechnica

lol, I'm sure that's comming, don't worry. My car is an early model 2002, so considering it has the AMG builders plaque on the S/C (which early models apparently didn't have), I'm guessing the S/C was already replaced by the previous owner. Hopefully the I/C was replaced

If/when my S/C goes, I'm considering a turbo build.

BTW, do you guys think I'm looking at just the rubber O-ring then? A bit disappionting since the hose itself is quite new. I noticed that a lot of online stores sell the entire hose with the O-ring on it. Can I buy just the o-ring seperately? Anyways, will pull apart tonight to confirm it's not a cracked rad neck. I was losing coolant in the overflow tank and my coolant systems are isolated w/ the needswings iso kit, so I knew it wasn't my S/C. Had to be something on the engine side.

thanks.

Autotechnica

The C55 probably didn't suffer from the Valeo gycol contamination issue since it's already a later M/Y. If the neck is cracked, might try repairing with JB Weld. I've rebuilt cast aluminum waterpump housings from JB Weld that held without problems.

Gramma_Benz

is your coolant clear? my mechanic put a green dye in mine to help trace any leaks. Then he uses a black light and the coolant glows to see where its leaking.

trbo2nr

Mine takes about 18 days or so, then low coolant comes on. Dealership pressure checked it and was fine. Maybe on the next nice day, I will see if I can find where the coolant is going. My car runs great, nice and strong with 103k on the odometer.

Bob

Speedriven1

Very common issue. Either its the hose coupling itself or a hair line crack under the hose in the radiator.

trbo2nr

Thanks. Will check...It's been bugging me and I finally have time to look at it this weekend. I've been riding around with the MB coolant premixed in a jug- tucked in the trunk...

johnng117

My leak was the intercooler, small crack on the sides. Very hard to see until we took out the intercooler to pressure test.

trbo2nr

Oh ok. Good to know and thanks.

Bob

trbo2nr

Looks like the coolant tank is at fault. It appears the seal where the black top portion meets the white/clear bottom. My question is whether or not I need to order oem or aftermarket? oem looks like $130 vs others are much less.

Bob