Hello,

The vehicle is 1987 300E 3.0L L6 103.983.

How is the cooling system bled? WIth the engine running or off? Engine cold , or warm or hot?

There is a bleed bolt on top of the cylinder head towards the front. I also see a small bolt in the top center of the thermostat housing.

Ideas?

there is a plug on the cylinder head towards the front (14mm if I remember correctly) and you pour coolant until it flows out of there then you put the plug back in and fill the rest of the way.

start the car with the heater on full.

with a completly empty system(drained crankcase) your car should take 9.5 liters of coolant

more info:

http://www.w124-zone.com/downloads/MB%20CD/W124/w124CD1/Program/Engine/103/20-0100.pdf

I've never had a problem. The system will self bleed. Add fluid slowly and when the expansion tank is near full bounce the car up and down a few times. That might drop the level so repeat until the tank won't accept any more fluid.

Start then engine, hold revs at 1500. and with the cap off wait for the thermostat to open. When it does the level in the expansion tank will drop, so add fluid as required.

Put the cap on and go for a short low speed drive. Then check and correct level as necessary, and do this for the next few cold-hot-cold cycles.

System capacity is about 12 quarts, so I fill with 6 quarts of Zerex G-05 and finish off with distilled water.

Duke

The best way to fill up these old engines is to first fill the engine from the top radiator hose into the engine, then connect it and fill from the tank. The radiator then fills up.

You can fill from the tank alone, but very slowly to prevent gurgling air locks.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)