87 300e leaking coolant from radiator fitting

[dirtysocks]

My 300e has begun to leak coolant. It appears that it is coming from the highest metal fitting on the left hand side (when looking at it) of the radiator. Is this the tranny coolant pipe?

How would I fix this? I found little when I searched. Is there an o-ring inside this fitting, or is it straight metal to metal? Do I have to buy the whole replacement pipe to fix this, or worse, maybe a new radiator?

Thank you for your time.

[dirtysocks]

In this pic, the fitting that I believe is leaking is being removed. anyone know what I can do about this? Is this uncommon? It seems like the more common leak on this side of the radiator is the lower, third fitting, under the second tranny cooling line. should I check this, too?

thanks for your time.

[dakota]

Personally, if this was my original radiator on my 87 300E, I would replace the radiator, no questions asked. I have heard of so many (and one personally) that seem to last about 100,000 miles or 10 years and then crack at the upper left main hose neck. The replacements have a reinforced neck.

The fitting you are indicating on the right side is for the transmission fluid hose. Is there a crack there? What is leaking? Coolant or Tranny fluid?

[dirtysocks]

The radiator has a sticker on it that says "nissens", and made in sweden. Is this the oem radiator for my car?

Definetely coolant leaking. It forms in small puddles on the bottom tray. Where would I look for tranny fluid in this area? On rare occasions, I smell burning tranny fluid, but this could be from anything.

No visible crack on the fitting, just a line of coolant running from it down to the other tranny cooling line.

[compress ignite]

Time to start pricing radiator...just in case.

crazy me , I tried the "fix the plastic tank + aluminum tabs route on a W126"

Aluminum after many expansions and contractions (the tabs that hold the
PLASTIC tanks onto the aluminum radiator core) suffer from crystalization.

And, what German engineer was smoking What, when He (I know no woman
would come up with such a Detroit idea) decided to machine plastic for
metal A.T.F. fittings?????????????????????????????????????????????????

[I bought an aftermarket old stlye COPPER radiator for the W126!]

[dirtysocks]

wait a minute... is the tranny cooled by sending Tranny fluid up to the radiator, or by sending coolant back to tranny? I seriously don't know (damn newbie). Could this be tranny fluid leaking out then? Thanks.

[donbryce]

Transmission fluid goes through radiator to be cooled, in a separate section of the radiator core from the coolant being circulated from the engine. Transmission fluid is reddish or reddish/brown and feels slippery when rubbed between the fingers. Your coolant could be brownish (MB) or green (not good - change it ASAP).

[dirtysocks]

Okay. The metal ATF fittings on the rad are definitely leaking coolant! I am certain this is what it is. Is the coolant leaking into the tranny fluid? Does the tranny fluid continue through a seperate metal pipe inside the radiator, with coolant surrounding it? Do I need a new rad.?

Thanks.

[Gilly]

Yes, I'd say a new radiator.
The transmission fluid is extremely hot and is cooled by circulating it through a wound copper coil inside the side tank in the radiator. It's rare that transmission fluid will leak into the coolant inside the radiator, but it has happened. I really doubt this is the case here.
The new radiator will have the new transmission cooler (not availble as a seperate part).
Gilly

[donbryce]

I'm just a DIY'er, but can't help commenting...If you are certain that this is coolant leaking out at the ATF fitting, and Gilly is correct, which I'm sure he is too, then isn't it likely that the leak is coming from around the fitting, not from inside the copper tube or fitting itself that contains the ATF? Perhaps this can be repaired with JB Weld or something, if the rest of the radiator is still in good condition...just a thought

[haasman]

Try removing the fitting nut hold the line to the radiator. Check that it is good and there are no burrs on the fitting to the radiator.

Inspect the fitting attachment at the radiator for cracks and the line itself. Reattach and see if it continues to leak. If so .... get a new radiator.

BTW-Don't use the green type antifreeze.

Haasman

[MB STARS]

124 Radiator price has been drop from $420.00 two years ago to $184.00 today $184 for Mercedes OE Radiator is VERY GOOD price....don't wait before the price go up again.

[DanielW]

They are not OEM. That was likely Bosch brand. the one Nissens brand I have seen did have the reinforced upper neck so in that regard may have been better.

Use only MB coolant and the plastic parts seem to last longer.

If there is ANY possibility that coolant leak will become serious I would change out the radiator completely.... overheating can ruin the entire motor and break the Bank $$Money for maintence is never wasted, since MB motors will outlast the entire car if cared for well and oil/filter changed regularly.
DanielW

[G-Benz]

The OEM brand of radiator is Behr. I believe Bosch manufactures electrical components...

...both Behr and Nissens reissues have the upgraded reinforced neck.

[DanielW]

That was my "senior moment". I thought Bosch didn't look right but could not remember why??? Behr it is.

Daniel W.
I WAS correct, however, about the logic of replacing any radiator which is questionable regarding leaks!!

DanielW