Bummer...it may be new radiator time.

[boneheaddoctor]

Well I noticed my coolant resivour tank was unusually dark at Johnhef's GTG today....but motor was too hot to play with it....well its got something brown in it...not black not redish....but brown.....slight oils sheen but no clumps floating as I have seen with oil....lettting it set to see what floats to the top overnight......I'm guessing Transmission fluid as there is a mahogany tone to the color of the tank. This is a major drag....trans fluid looks fine at the stick...but we shall see. I may pull and flush my parts car radiator and install that during the week if nothing else.

Well if unless somebodies been taking a dump in your reservoir, sounds like tranny fluid!

[boneheaddoctor]

Well what I meant by brown is a residue on the cap and neck.......

That means pinhole leak inside the radiator from the Trans cooler....damn...this is the only registered car with working A/C I can drive to work. Well trans fluid should float..let see what I find in the morning.

Just changed the oil 2,000 miles ago and all was fine then...

[t walgamuth]

reddish?

tom w

Originally Posted by t walgamuth

reddish?

tom w

No, he said it was brownish!

[t walgamuth]

should be reddish. brownish sounds like ordinary coolant system sludge.

tom w

[boneheaddoctor]

The outside of the tank looks a dark reddish brown of real old rosewood furniture....or Mahogony...

the residue wiped off the cap and neck were brown when wiped on a paper towel...

Thats why I am leaning to trans cooler leak inside radiator.

Originally Posted by boneheaddoctor

The outside of the tank looks a dark reddish brown of real old rosewood furniture....or Mahogony...

the residue wiped off the cap and neck were brown when wiped on a paper towel...

Thats why I am leaning to trans cooler leak inside radiator.

Come to think of it, I had a 90 240DL, with this problem. It began by the transmission acting up. It was the radiator. I remember a color you described as mahogany. I remember flushing thr tranny with cheap tranny fluid, about five gallons before a final change to better quality fluid.

[boneheaddoctor]

Originally Posted by BusyBenz

Come to think of it, I had a 90 240DL, with this problem. It began by the transmission acting up. It was the radiator. I remember a color you described as mahogany. I remember flushing thr tranny with cheap tranny fluid, about five gallons before a final change to better quality fluid.

Well tranny isn't acting up...I think it started in the last few days.....but yes I expect to have to flush the tranny afterwards (and drain the converter) sucks the antifreeze is only 4 monts old. But to be fair I believe this radiator to be original.....and thats 26 years of service...

[t walgamuth]

it is unusual for them to leak into the rad. i think. i have owned prob 30 benzes. havent replaced that many rads maybe three or four. always external leaks in my experience. or internal blockage which when boiled becomes a leak.

tom w

[Hit Man X]

Originally Posted by BusyBenz

Well if unless somebodies been taking a dump in your reservoir,

LOL

But sounds like internal stuff, perhaps rust?

[boneheaddoctor]

Originally Posted by t walgamuth

it is unusual for them to leak into the rad. i think. i have owned prob 30 benzes. havent replaced that many rads maybe three or four. always external leaks in my experience. or internal blockage which when boiled becomes a leak.

tom w

Last time I had a trans cooler leak into the radiator it was a 1973 Olds cutlass I had when I was in College.

[t walgamuth]

cutlesses. my bro had a 72. he loved that car. they had a rep for being one of the best us motors ever made, up til then.

tom w

Is this your w116 or your w123?
You could always remove the trans cooler lines from the radiator, put a pressure gauge/plug on one end and charge it with air.
If you get bubbles out the top of your radiator or your gauge looses pressure after the air is applied, you have a leak.

Not sure the feasability of this test but its probably what I would do
How was the GTG?

[Johnhef]

You know, I had noticed that when you were here but forgot to mention it to you. I hope it is just the radiator. I had an '03 E500 last month that shifted like crap. Same thing, trans cooler in the radiator had a leak and was letting coolant into the trans system. That car got a new radiator, torque converter and transmission.