Radiator Leaking when car is not running

[Lou F]

Hello Pogoda Masters,
I took my 1969 280SL Automatic to a Saturday Cars and Coffee and after the car was sitting in the parking lot for 2 hours someone pointed out I had a coolant leak.
The leak is on the right side of the radiator above the bottom tank and above the outlet connection.  My car has air conditioning so I can't get a good look at the core.  The strange thing is the leak stops when the car is running and does not start leaking until the car is off for 10 minutes.  I live near Philadelphia, PA and there are a few radiator repair shops but I do not think they have experience with our cars. Since I can not remove the radiator myself so I was thinking I can take it to my mechanic and have them pull it out and send it to the shop. Personally I don't like middle men but I don't think I can get around it.
When one of you guys encounter a leak like this was is the course of action and what would be a cost estimate?  I don't want to die from sticker schock.
Here is a little background.  I did not have any cooling system problems for the last 5 years.  The previous owner was my father-in-law and I found recites for cooling system repairs that when into the thousands of dollars.  The radiator does have a good size dent on the bottom where the drain pep-cock drain is located, but the leak is not from the dent as far as I can tell.

Thanks for the help.
Lou.

[Mechudo62]

I just bought a brand spanking new OEM "Behr" radiator from the Mercedes-Benz Classic Center for my 1970 280 SL that cost me $900.00. Labor to install either a new or refurbished radiator is the same, but the extra peace of mind of the new Behr radiator is worth the price. Don't take chances with the cooling system, invest in your Pagoda's reliability and prevent costly engine damage caused by overheating.

[Jordan]

Lou, before you start pulling things apart, make sure you check that all your clamps are tight and none of your hoses are cracked.  Try and find the source of the leak before you do anything.  Odd it doesn't leak when the system is under pressure, unless the pressure is helping seal the leak.

[mdsalemi]

Hi Lou,

For what its worth, I had the same kind of leak in the same area, and it turned out to be the lower radiator hose clamp. Needed some tightening.
If that doesn't do it, these radiators are easily repaired. If you don't feel comfortable with your own knowledge, call Tony Labella in Cherry Hill, or Bob Platz at Precision Auto Works in Camden. They might tell you the radiator shops they trust in the greater Philadelphia area.

[badali]

I just had my 230SL radiator recored this year.  I took it out with my son.  We did not remove the hood.  I pulled the car up on ramps and removed the battery and air cleaner.  Then we removed the 3 bolts on each side while I laid under the car and dropped it out the bottom.  The recore was $400.  The car no longer leaks and runs cooler.  It was not a bad do it yourself job...

[Lou F]

Sorry for not replying sooner.
Thank you all for the advice.
I did notice coolant stains on the return hose and clamp and it could be the source of the leak. I guess coolant could squirt out between the hose and connector and make its way to the front of the radiator.   I need to get under the car and get a better look.