If anyone thinks this post should come down - just say so. I will delete it.

Few cars run as long as ours. Long life , high miles.
Few people get to perform certain kinds of maintenance like we do.

It has been 5 years and 100,000 miles since I last removed the radiator and
cleaned out the fins on the 300SD.

It was running warm on my daily mountain climb and when I removed the radiator and held it up to the light - none came through.
All the fins were clogged.

This is basic radiator cleaning, I start with air, then water pressure, then shop vac.

Still a lot of debris left in the cooling fins. I would have used a pressure washer if I had one.

Read a few years back here about a radiator cleaning solution and decided
to use readily available drain cleaning gel.
Some of my stuff is hair like, and my prior experiments with drain cleaner proved that it dissolves hair.

So I cut a board to fit the radiator (16 7/8 inches by 22 inches I think).
Covered it with a 13 gallon trash bag to resist getting eaten by drain cleaner.

Clamped the bag covered board to the radiator so now one side is blocked
and the solution will settle in the fins and go to work.

I placed this in my wheel barrow (only thing big enough to hold my radiator).
Poured a 64 ounce bottle of drain cleaner on and sort of brushed it in.

After a few hours drained off the wheel barrow in to a bucket and poured the stuff over the radiator again.

Waited overnight and next day went back to a high pressure water rinse
(brass nozzle for driveway washing). Then air pressure.

I wrote this post because this cleaning is the best I have ever gotten.
Short of taking it to a radiator shop for a boil and cleaning this is the best
I can ever imagine getting at home.

All the fins are clean and free of debris.
And my temperatures are now stable even under load.

With rising summer heat here I notice temp changes (was 90 F this last weekend). Now I am ready for summer.

Anyone else used drain cleaner to clean out the fins ?
You folks thinking their radiator is clogged inside - have you checked the
airflow and the fins ?

__________________
80 300D 340K Owned 30 yrs
83 300SD 440K Owned 9 yrs - Daily Driver 150mi/day
02 Z71 Suburban 117,000
15 Toyota Prius 2600 miles
00 Harley Sportster 24k
09 Yamaha R6
03 Ninja 250

Wow. That's pretty thorough. I usually just place Simple Green (or Castrol Super Clean) into a pressure washer with a spray wand. I then spray down the radiator (without removal from the car) on both sides. I wait for 10 minutes for it to work. I then use a garden hose to spray the fins both front and back.

This method is easy, only takes 15 minutes. It works for dirt and grease buildup.

Your method sounds much more thorough. Nice job!

-PE

__________________
83 240D - 4 speed manual - Manilla Beige
189K miles, Tachometer mod, cool wooden shift knob from PeachParts, CocoMats, Original factory paint, manual windows, manual sunroof. Starting to add AudioWrap to this car too!

I use the simple green method with the radiator out of the car doing a drain and flush. I would guess that we all see different types of debris buildup depending on where we are. I don't see so much hair like stuff, but more of a greasy buildup with a few leaves and organic debris. And pine needles. I hate pine needles.

__________________
1985 300D-189k The 'UD', Ivory and Pinkamino
1979 300D-211k Dark Gray, Parchment
A 1980 Harley-~166k and
A 1994 Ford diesel pickup-349k and
A 1990 gasser Volvo wagon-145k

Be sure and rinse it really REALLY well, and don't let it sit for more than 10 minutes. Radiator tubes and fins are very thin, and Simple Green is corrosive to aluminum:

"aluminum is a soft metal that easily corrodes with unprotected exposure to water. The aqueous-base and alkalinity of Simple Green All-Purpose Cleaner can accelerate the corrosion process. Therefore, contact times for unprotected or unpainted aluminum surfaces should be kept as brief as the job will allow - never for more than 10 minutes. Large cleaning jobs should be conducted in smaller-area stages to achieve lower contact time. Rinsing after cleaning should always be extremely thorough - paying special attention to flush out cracks and crevices to remove all Simple Green® product residues. Unfinished, uncoated or unpainted aluminum cleaned with Simple Green products should receive some sort of protectant after cleaning to prevent oxidation. "

From: http://www.simplegreen.com/solutions_faqs.php?search_query=aluminum

__________________
'98 E300 turbodiesel

I take a more preventative approach and have a screen of fine wire mesh covering my radiator. Think old fashioned back porch screen door material.

It doesn't keep out the finer dust particles, I'm sure, but keeps the bugs and larger road detritus out.

__________________
1974 240D "Boldie" 170K.- New timing chain/freshly rebuilt IP/replaced valve seals/injectors/upgraded stereo/new Bilsteins with Yokohamas/fresh paint and rocker panels plus lots of welds.

Do you know what percentage of blockage the mesh creates? I looked at some mesh material one time for this same purpose (on a different car) and found the mesh had only about 68% of open area. I'm not sure that reducing airflow by 32% is a good idea. Although if yours is of a more open design, it probably works fine.

__________________
'98 E300 turbodiesel

I've been doing this for years. well when I got the car from my grandmother she had some screen on there. I've just kept up with it.
I can't tell you about the air flow through the screen, but I can tell you that since I went to an electric fan, the fan only comes on in traffic in the summer time. so I don't think the screen it hurting anything. And it really helps keep the radiator clean. My grandmother lives near the rice fields of the central valley, and my dad lives on a lake netorious for its nats. The bugs can be thick in both places, the screen catches the bugs no problem.

__________________

I never leave any cleaning fluid on aluminum very long, thanks for the heads up about the protectant. I'll have to look into that. I've been thinking about using a product called 'Gibbs', it's been recommended for bare aluminun to me before. Anyone ever use it?

__________________
1985 300D-189k The 'UD', Ivory and Pinkamino
1979 300D-211k Dark Gray, Parchment
A 1980 Harley-~166k and
A 1994 Ford diesel pickup-349k and
A 1990 gasser Volvo wagon-145k