300CE 175k
I just finished replacing upper timing chain seal, tensioner, belt, etc. I pulled the radiatior to have some more room to do the work. Got everything re-assembled and running smoothly. No more oil leaks, but apparently I did not handle the radiatior carefully enough. I must have bumped something. It is now leaking at the crimped plastic-to-metal seal on the driver's side. The oil drips in my driveway have been exchanged for coolant drips. Damn. So I have to put in a new radiator. Ordered it from Phil.

Would it make sense to do a thorough flush with the old radiator in? Then drain, install new radiator and refill? Or install new one then do a flush? Does it matter? My search of the site said to use citris flush. Can anyone reccomend a brand?
Thanks

Definetly flush with the old one! Any crap in your water pump, hoses, or reservoir will land in your radiator....

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2006 BMW M5 "Heidi" @ 109,000 miles
2005 MBZ C55 AMG "Lorelai" @ 165,000 miles
1991 MBZ 300E "Benzachino II" @ 165,000 miles
1990 MBZ 500SL "Shoshanna" @ 118,000 miles

(On the hunt for a good used M103 engine as of 6/10/23, PM me if you have one to sell!)

Why not try to crimp the crimp a little? (of course there is the risk of breaking something, but still...could save some $$)

No sense in flushing with the old radiator in place. Besides, I imagine most of the "flushing" would be for the benefit of the radiator anyway.

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It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D

There are some strategically located flushing valves located throughout the system, one is at the lower right (passenger) side of the radiator, the other below the exhaust manifold, and the vent above the thermostat. I would imagine that with the radiator removed and a garden hose you could do a really nice job of flushing out the block, head, and water pump. After that, install the radiator and plain water. Warm up the system, turn on the heat, and then empty the system. I wouldn't run it with plain water for long since it can damage the water pump due to lack of lubrication. I am always very hesitant to load up the cooling system with a flushing chemical, since I think the only thing it is likely to do is deterioriate the fragile head gasket. (and it's not wise to let it flow all over the driveway).

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89 300te 222,222
92 300e 190,000

You want to do a citric acid flush -- if I remember correctly, this is a 10% solution, run engine for 10 min, drain, fill with clean water, circulate, drain, repeat until clear (and no longer acidic). Doesn't really matter if you do this first, or replace rad first, athough it's nice to install a clean rad on a clean engine.

Replace the thermostat, too, and hoses if at all hard.

Any citric acid (without sugar, of course!) will work -- I'd try to find an industrial source. I missed out on a 50 lb bag at work, didn't get around to telling the hazardous waste guy I wanted it before he got rid of it. The MB stuff is ridiculously expensive.

You will need about a kilogram (2.2lbs) of the stuff.

Sold in the grocery store as DipIt coffee pot cleaner, but you won't want to buy a kilogram of it that way!

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

One day and I have my parts from Fastlane Phil is the best.
Larry - Tried to re-crimp with those wide jawed vice grips - made it worse. And I don't ever want to risk over heating.
RP - Mine's a M103 so I will risk a gentle flush.
PSFRED - What can I say? Couldn't have done the tensioner, etc. work without your posts. Will continue to follow your advice. Crocus through the snow today here. Thanks again.