Best way for DIY'er to flush all old coolant out of system?

[steved0x]

I am doing a WP/Thermostat change soon and I do want to flush all the old coolant out of the car because I don't know what is in there, and I am replacing with OEM Porsche coolant. I was going to buy many gallons of distilled water, and then do one of two things:

1. Remove the drain plug at the bottom, and then run the engine while I continuously add distilled water, until it comes out the bottom clear. Then disconnect the big hoses and like it shows in the 101Projects site to remove the remaining distilled water before finishing the job and refilling with 50/50

2. Remove the hose that connects to the thermostat, and then run the engine while I quickly add distilled water to the system, to pump out the old coolant through that disconnected hose. Then shut down, and drain/disconnect the other big hoses/drain as described in 101Projects.

Are these overkill (or bad/dangerous)? If I drain using the drain plug and then disconnect the hoses as described in the 101Projects will that do it for me? Do I need to turn the heat on?

I *think* my old coolant is pink but I am not 100% certain. it might be green. I can check it tonight.

Steve

PS for refilling I have the airlift tool and a compressor. I used it once already when flusing my Tacoma (using method 1 above) and it worked great at refilling.

[woodsman]

In 101 Projects Wayne instructs to position the heater to HI and to turn the fan on and key to it's first click- this allows the heater core to empty . He also instructs to detach the heater lines(2). I am in the middle of changing a rad( and since I'm in there...) and had access to the lower rad hoses as well but have realized that the center rad must still be full...I think I'll blow this out as I'm worried about gelling with the new Porsche coolant.

[BoxsterSteve]

When I did my coolant flush/water pump/160F thermostat job last spring, I drained the front of the system by lowering the back of the vehicle off the jack-stands so gravity could drain it out the two large hoses you disconnect at the engine.
I got out 19 of the alleged 20 litres of coolant this way.
Close enough for me.
I know my car had Porsche coolant in it originally, so I didn't lose my mind by leaving a bit of old stuff in the system.

[j.fro]

Here's how I got all of the system flushed on my 996:



Hook the pic flush tool up to the thermostat hose. This will backflush the system. Use the garden hose for this, then plumb in a funnel and run a couple of gallons of distilled water through. You'll be in good shape.
Be careful about how much pressure you use...the 996/986 system only goes to about 20 psi, which is pretty low.

[Gelbster]

The troublesome part is the refill. Problem with large amounts of air trapped. This can cause overheating and worse ,so it is worth doing some searching to learn how to prevent ait getting trapped.
You'll find mention of "airlift","UView" and similar tools. There are cheap chinese tools on Ebay that seem to work quite well. Just search for terms similar to :"Cooling System Vacuum Radiator Kit Refill & Purge ".
Many newer cars need this ,so a universal kit is probably a reasonable addition to your tool kit.

[steved0x]

Originally Posted by Gelbster

The troublesome part is the refill. Problem with large amounts of air trapped. This can cause overheating and worse ,so it is worth doing some searching to learn how to prevent ait getting trapped.
You'll find mention of "airlift","UView" and similar tools. There are cheap chinese tools on Ebay that seem to work quite well. Just search for terms similar to :"Cooling System Vacuum Radiator Kit Refill & Purge ".
Many newer cars need this ,so a universal kit is probably a reasonable addition to your tool kit.

I've got the UView airlift and it worked like a champ the one time I have used it so far, on my Tacoma. I may try to tackle the job this weekend so I will report back.

Steve

[BoxsterSteve]

I borrowed an Airlift to refill mine.
Wow.
It drank in nearly 6 gallons in under 4 minutes, and no air pockets to worry over and try to burp out.