The GUNK? It does list citric acid as an ingredient ... is it just less harsh? It says water, citric acid, tetrasodium EDTA, potassium citrate and diethylene glycol butyl ether. I could also get a bottle of the Shout that dieselgiant uses instead.

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1987 300D, arctic white/palomino--314,000 miles
1978 240D 4-speed, Euro Delivery, light ivory/bamboo--370,000 miles
2005 Jeep Liberty CRD Limited, light khaki/slate--140,000 miles
2018 Chevy Cruze diesel, 6-speed manual, satin steel metallic/kalahari--19,000 miles
1982 Peugeot 505 diesel, 4-speed manual, blue/blue, 130,000 miles
1995 S320, black/parchment--34,000 miles (Dad's car)

Before dumping any type of flush in see what the coolant looks like coming out. If there is not a lot of particulates floating in it, I would flush until the water comes out clear and refill with proper coolant.

There is a way to draw a vacumn on the system using the overflow hose but for the life of me I cant remember the specifics.

As far as the disposal do you have a 5 gallon bucket? dump the old into that. The parts store around here take old coolant I would check around where you are at.

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86 300SDL. 250,xxx on #14 Head. One eye always on temp gauge.. Cruising towards 300K

What is the exact name of the Gunk product?

http://www.amazon.com/Super-Heavy-Duty-Radiator-Cleaner-32/dp/B000ABE942 Gunk Super Heavy Duty Radiator Cleaner. Looks like there are a few milder products I could try.

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1987 300D, arctic white/palomino--314,000 miles
1978 240D 4-speed, Euro Delivery, light ivory/bamboo--370,000 miles
2005 Jeep Liberty CRD Limited, light khaki/slate--140,000 miles
2018 Chevy Cruze diesel, 6-speed manual, satin steel metallic/kalahari--19,000 miles
1982 Peugeot 505 diesel, 4-speed manual, blue/blue, 130,000 miles
1995 S320, black/parchment--34,000 miles (Dad's car)

I would not use that on a reasonably well-maintained system. Green antifreeze isn't a major issue per se, it just doesn't have as long of a service life as the "proper" HOAT formulation.

Please, please don't use the the citric acid flush on our old cars! Look under my username for more in depth discussion about it. Water is fine.

I toasted two radiators, a water pump, and created a ton of work for myself.

For burping: If you take the upper radiator hose off and fill that (fils the head), and then fill the radiator (or expansion tank on a 300D turbo), you don't need to burp neaery as much. I just put the car nose up on a hill, take the radiator cap off, and rev to 3k rpms a few times. Never a problem. And I have way more experience with flushing and filling than Id like :-)

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'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car