i got some engine coolant and wanted to ask you guys if this is fool proof? i have the bently manual but want to know if anything could possibly go wrong.. have you done this and was it easy?? i have an '87 240 Dl. Thanks!!!

Combine the other responses and you have the way to do it. If you have the plastic and aluminum radiator, be careful when disconnecting the lower radiator hose so you don't break the plastic neck the hose is clamped on. When you remove the thermostat, be sure to remember which way it is mounted and that the little jiggle valve is at the top when replacing. The only problem I've had is a leaking hose connection. After the engine gets hot and there is pressure in the cooling system, take a flashlight and carefully search for any leaks at the hose connections and watch the coolant level in the tank.

It's not hard to accomplish. There are several methods. What I did was remove the coolant filler cap, loosen the bottom radiator hose at the radiator and pull it off the radiator. Lots of coolant flowed out the radiator hose and radiator mostly into a clean oil-changing catch pan. I didn't flush anything out with water in my case because I saw no sign of any loose scaling, etc. Then I removed the thermostat which is really easy, 2 nuts, and put a new gasket on the thermostat which is cheap and simple. Next, I hooked up the lower radiator hose again, poured new 50/50 coolant water mix into the thermostat hole in the head to fill the block with coolant. Then I added coolant through the regular f!ller spot, at the overflow tank up to the correct level between the high and low marks. Next I topped off the coolant again at the thermostat hole in the head and replaced the thermostat with the new gasket. If the two radiator hoses are old, it's a great time to replace them before you start adding the new coolant. Finally, after all four radiator hose clamps are tight, I run the engine with the normal filler cap removed. Add coolant as necesarry. Measure how much fluid you removed and be sure at least the same amount of new fluid goes back in. Check it every morning for several days to be sure. Clean up the mess. It's poison to cats and kids especially. Good luck. This is just the way I do it. There are various way to accomplish the job.
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Thanks to everyone for the help, Doug C. 81 242 Brick Off Blocks, stock; 86 240, 129K, once in Rolling, now smashed quarter panel thanks to driver of an F150. Daughter safe in her Volvo.

13mm wrench loosens the brass valve on rear passenger's side of block. I have a section of clear tubing I attach after opening to drain into a container on the ground (expect two gallons). Remove radiator cap to increase flow rate. Flush with water- make sure heater valve is open. In subfreezing weather I premix the coolant and water to avoid possible unmixed water freezing (possibly not necessary but I sleep better). A water flush may leave some pure water in the system so I mix a little light on the water portion.

After pouring in the mixture start car and watch temperature gauge. Sometimes you can get an air lock at the thermostat and it will spike the temperature because coolant isn't really flowing. This will be something to really keep an eye on if the system didn't accept at least 7 quarts of liquid. Sometimes the air lock will be bridged if you allow the car to cool down after attempting to spike, other times it takes a couple of these cycles. If you really want to get on with it you can "burp" the system by loosening the thermostat housing to allow the air lock to escape.

Be aware that coolant is a poison that pets and children are attracted to because of its sweet taste.

Randy

This has happened to me on several different cars. What seems to work is as the car starts to run hot, I grab the upper radiator hose and quickly squeeze and release until you will all of a sudden feel that hose heating up.

Just a thought for next time.
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'75 Jeep CJ5 345Hp ChevyPwr and two motorcycles: it wasn't Volvos safety , it was Longevity that sold me