Oil cooler/radiator, rustproof

[HarryMead]

The oil cooler on my 280SL is steel and tends to rust.  I have a second unit which I bought new and installed, but it rusted after being caught in the rain.  I recently had it stripped down to bare metal and am painting with Rust-Oleum spray cans, beginning with the red primer.  I cannot figure out how to get the paint inside the chamber on the left side of the frame, which has three small holes therein.  I have the cooling fins pretty well coated with paint, but not the inside of the long, rectangular chamber which extends out on the left side.  Before I go to all the trouble of removing the radiator again, I would like to rustproof it to the extent possible.  I have been taking the radiators, water & oil, out from the bottom to avoid removing the hood, but it is still a big job for a non-professional.  Harry Mead (1970 280SL, no air conditioning, 4-speed)

[pkiefert]

I don't believe you're supposed to paint the cooling fins on any radiator type device as it degrades the heat transfer.

[George Davis]

Shooting from the hip here, but you might consider getting non-spray paint and thinning it down to the consistency of water.  Pour it into the chamber, cover the holes and slosh it all around, then drain the excess out.  Might work, or I might be nuts.  Another idea is to use an air brush, spray throught the holes and hope the mist covers everthing inside.

Pkeifert is right that cooling fins shouldn't be painted, but it's done all the time on the old copper/brass radiators.  In this case, since one must compromise between rust protection and most effective cooling, the best bet is to minimize the paint thickness.  I'd always assumed the oil cooler is aluminum, but I guess not.

George Davis
'69 280 SL Euro manual

[HarryMead]

quote:Originally posted by George Davis

Shooting from the hip here, but you might consider getting non-spray paint and thinning it down to the consistency of water.  Pour it into the chamber, cover the holes and slosh it all around, then drain the excess out.  Might work, or I might be nuts.  Another idea is to use an air brush, spray throught the holes and hope the mist covers everthing inside.

Pkeifert is right that cooling fins shouldn't be painted, but it's done all the time on the old copper/brass radiators.  In this case, since one must compromise between rust protection and most effective cooling, the best bet is to minimize the paint thickness.  I'd always assumed the oil cooler is aluminum, but I guess not.

George Davis
'69 280 SL Euro manual

Harry Mead (1970 280SL, no air conditioning, 4-speed)

[HarryMead]

I apologize for not doing this right the first time, but I thank you for your answer about the paint.  I will get the same paint in a can and thin it as you have suggested.  My oil cooler (1970) is definitely magnetic and too heavy to be aluminum.

quote:Originally posted by George Davis

Shooting from the hip here, but you might consider getting non-spray paint and thinning it down to the consistency of water.  Pour it into the chamber, cover the holes and slosh it all around, then drain the excess out.  Might work, or I might be nuts.  Another idea is to use an air brush, spray throught the holes and hope the mist covers everthing inside.

Pkeifert is right that cooling fins shouldn't be painted, but it's done all the time on the old copper/brass radiators.  In this case, since one must compromise between rust protection and most effective cooling, the best bet is to minimize the paint thickness.  I'd always assumed the oil cooler is aluminum, but I guess not.

George Davis
'69 280 SL Euro manual

Harry Mead (1970 280SL, no air conditioning, 4-speed)

[n/a]

I'm about to replace my radiator. How does removing from the bottom work as it sounds a lot easier than taking the hood off? I have access to a lift or ramps so this might be a good option.

Shawn Rock
Philly, PA USA
1968 280 SL 4 speed

[HarryMead]

Dear Shawn: I have owned the car, 1970 280SL 4 speed, for almost 34 years and have removed the radiator both ways, from the top and from the bottom, and I prefer the latter.  Tying the hood torsion bar and getting the hood spaced properly upon replacement are difficult for me.  The captive nuts in the hood where the hinges attach were a pain to find when putting back.  I don't remember any particular tricks in removing from the bottom.  I have always jacked up with a floor jack and set jack stands, insulated with rubber strips, under the side frame rails, but I am sure the ramps would work as well.  A lift would be the best of all.  The radiator is about 21 inches high so the bottom of the radiator must be elevated at least that distance from the floor, which should be easy.  Just drain both radiators and disconnect all hoses.  I think that I removed the battery, which is not too difficult when the oil hoses are disconnected.  I cannot remember whether the air cleaner housing need be removed, but that is easy.  I think that there is a braided copper ground strap which must be disconnected in the neighborhood of the battery.  My oil hoses disconnected easily with open end wrenches, but if you want to replace them, the connections to the metal pipes are best removed with six point tubing wrenches or 6-point crowfoot wrenches, one on the pipe and one on the hose.  The radiators are removed as a unit; I think there are three screws on each side.  I did not have a helper, just dropped them very slowly, and used boxes of the correct height to rest them on when reinstalling, but a helper would make it a lot easier when the last screw is taken out.  I hope that I have not omitted anything important, but it is an easy job for an amateur if one has patience.  After all, it is a hobby, not a job, and can be done slowly. I learned not soon enough not to be in a hurry, or one can break something irreplaceable.  If I can do it, anyone with patience can.  Sorry to be so verbose.

quote:Originally posted by srock

I'm about to replace my radiator. How does removing from the bottom work as it sounds a lot easier than taking the hood off? I have access to a lift or ramps so this might be a good option.

Shawn Rock
Philly, PA USA
1968 280 SL 4 speed

Harry Mead (1970 280SL, no air conditioning, 4-speed)