Removing / replacing end tanks is a complicated not always successful operation that takes special tools. ( The tabs are usually partly cracked during the initial bending and won't survive another open close operation. )

My 97 SL had weeping end tanks and I contacted Behr for service centers. Tools to do the repair are not really out in the wild so I ended up replacing the rad.

Years ago I has a customer with a Renault Fuego that removed the side tanks and epoxied them back on. It seemed to work as long as I saw the car.

I would first try AlumaSeal, which is powder you shake into the coolant. You need to put in the top hose, not the remote reservoir. It has worked for me on several cars to seal small coolant leaks, and it is more benign than the silicate solutions which can clog your radiator.

I wouldn't put any of that stuff in a car I planned on keeping. I have a feeling the heater core will be blocked in no time.

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$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment

I've used the AlumaSteel a lot over the years, also the small rubbery black ball sealant. Never had a problem with a heater core getting plugged.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Epoxy does work for a bit but may fail since it is less flexible than the plastic tanks.

Plastic tanks fail a few ways, Pressure cycles and degradation of plastic.

Everytime the cooling system builds pressure, the tank balloons out. The constant flexing eventually leads to a crack. Filling the crack stops the leak but does little to keep the tank from flexing. If you do make this type of repair, be sure to get epoxy in the crack and spread it around as an reinforcement. JB weld is more of a putty and seems to need help sticking to the surface.

Brass tanks aren't immune to flexing either.

When plastic degrades over time, epoxy only works in the very near term as there just isn't enough stuff left to glue to.

I have used JB Weld on radiator tanks with poor results, as in, it worked for a few months and fell off. I am with the "radiator sealant" group. I have Barrs Leaks in my 606 now. It has sealed a head gasket that was leaking water to the outside, for the last two years. I like this brand as I can mix it with removed coolant and allow it to settle for a few minutes before pouring about 3/4 of it back in. This allows the removal of the large particles that might plug anything important and would certainly settle out in the block. I have never plugged a heater core, that I know of. About 30 years ago some of the manufacturers of antifreeze sold a coolant with leak sealer in it as a value added. I'm guessing they stopped because brown sludge on the bottom of the jug was off putting to those who forgot to shake the jug.

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'97 E 300 D

I have drug more than one BMW in off the interstate with cracked plastic cooling system parts that have been successfully repaired with JB Weld radiator repair material and sent on home. If you are in a bind then I say use it. Otherwise the most reliable, long term solution is to replace the radiator every say, 250k miles.

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Jim

I once used a syringe (no needle of course) to inject epoxy into a radiator crack. This caused the epoxy to "splay" on the inside, forming an nice seal on the interior of the crack. Never did leak again.

It's too bad you only got 200K miles out of the first one. You suppose it's still under warranty?

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Jackson
Rockford, Michigan

1985 500SE gray market
1982 Porsche 928
1985 Mercedes 300CD X 2

LOL....

mine's got 320k on her

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-Justin

I believe in extreme automotive perfection whenever possible.......there is no such thing as "It doesn't matter" !!!

1985 300 CDT - 287k miles

1980 240 D - 340k miles

With extras !!

http://facebook.com/BenzDieselTuner

http://facebook.com/SWFLAlternativeFuelsClub

http://facebook.com/SWFLBenzClub

http://SWFLBenzClub.com

i use AMSOIL coolant, which also has this feature.....it "foams" (technicaly, not literally) out through any hairline cracks, such as block, head, gasket, radiator cores, etc, and this then hardens, which stops the leak....and it stays a nice bright yellow so you can see where you had a leak.....neat stuff.....

i cant remember seeing any coolant with stopleak before, as far as i recall.....

though this is happening constantly, and hardening up as it should and stopping the leak, when the temp cools off, probably due to the contraction, it begins to seep out again.....

i appreciate all the input so far.....between everyone's experiences, i can make a educated assumption of what i am going to do...

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-Justin

I believe in extreme automotive perfection whenever possible.......there is no such thing as "It doesn't matter" !!!

1985 300 CDT - 287k miles

1980 240 D - 340k miles

With extras !!

http://facebook.com/BenzDieselTuner

http://facebook.com/SWFLAlternativeFuelsClub

http://facebook.com/SWFLBenzClub

http://SWFLBenzClub.com