xman11 asked if anyone tried pushing the coolant out with a vac blower. So, I tried this today. It worked very well in that it was possible to consistently remove 3/4 gallon of fluid. This is about 1/2 of what the system holds, which is enough that when the remaining fluid is "clean" distilled water it is easy to install the new 3/4 gallon of 100% strength coolant.

Here is what I did:
1. Ran engine with heater on high and heater fan on low. Just until coolant was warm to hot in expansion tank and blown heater air was medium hot. These two conditions tell you the cooling system thermostat is open
2. Drained old coolant by pulling bottom radiator hose
3. Flushed sub-portions of system with distilled water. Achieved by pouring clean distilled water down top radiator hose in both directions at top bleeder valve and into expansion tank. Removed bleeder valve sleeve to achieve this. I used 3/4 to 1 gallon of water to do this. Water was introduced to hoses and tank by funnel.
4. Used vacuum cleaner blower mode to push distilled water through system. Slipped the blower hose inside the top radiator hose in both directions. Top bleeder valve was removed in step 3. Slipped blower hose inside expansion tank. Used wet shop rag to seal tank opening.
5. Slipped bottom radiator hose back on. No clamp and only about half way down on pipe fitting. Slipped bleeder valve in top hose back into hoses. No clamps and about 3/4 way on.
6. Filled system with clean distilled water in both directions of top hose and expansion tank. Note: pour slowly and air is displaced
7. Repeated step 1; also had top hose bleeder valve open and expansion tank top off
8. Repeated step 2
9. Repeated step 4
10. Repeated step 5
11. Completed one draining of old fluid and 3 "batch" flushes. Fluid drained after 3rd batch flush was almost as clear as water
12. Slipped bottom radiator hose all the way on to stops and clamped it. Filled system with 100% strength coolant. Poured coolant into top radiator hose, both directions, and expansion tank. This is where slow pouring really pays. Reinstalled bleeder valve sleeve and clamps.
13. Hosed spilled coolant from underside of car and anywhere in engine bay that coolant spilled. Applied armour all (silicon spray) to rubber clutch actuator boot and a few other rubber bits that were contacted with coolant
14. Ran engine with bleeder valve open and expansion tank lid off. Watched air bubbles and steam emit from valve and tank. Let engine get hotter this time and add clean distilled water when level in expansion tank fell

The catch pan I used when draining fluid was designed for holding mixed cement when laying bricks. Long, deep enough, but sides not too high. You can get them at Ace hardware.

Next time I'm going to insert a T valve into the coolant hose. Instead of using it to introduce water at moderate pressure to flush system, it'll be discharge (effluent) valve when the engine is running. I'll introduce clean distilled water through the expansion tank at a rate equal to or greater than the discharge rate. I've had automobiles in the past that had valves like this at the bottom of the radiator and on the engine block. A hose will be temporarily connected to the T valve so the discharged fluid is conveyed to a catch can.

Additional note: if doing batch mode, don't put cold distilled water in a very hot engine block. That'll shock the metal and crack the block. I have seen this occur in the hot desert outback in Utah by a traveler who did not know much about automobile maintenance. This is one of the reasons I didn't let things get any hotter than described. When flushing with the system open (i.e., dynamic; see suggested T valve use), potential block cracking is avoided.

 

Haven't posted much in recent years, but since my t-stat finally gave-up the ghost, I used the opportunity to also flush the coolant. With only 65k miles on my first week 2003 (Sep 2002 build), I don't drive her all that much...

I used the shop vac method, so thanks much for whoever came-up with the idea. Of note, I also use such for blocked drains...

The problem for me is that I have a couple of the larger shop vacs, with 2.5" hoses. I found a really cool reducer though (at HD and Lowe's) that worked perfectly on different MINI hoses.

Just figured that I'd share...

 

- Is it possible to drain the whole system without using a vacuum? if so how?
- how much fluid will be needed if the old fluid is drained?

 

1 1/2 - 2 gallons of coolant.

This DIY Coolant Change may be of some help to your questions as well.

-Luccia

 

Yes. By removing the silver plug near the rear center of the engine block, and releasing the lower radiator hose, ~99.8% of the entire cooling system will be drained. The remaining bits from the waterpump and lower radiator, can be flushed out with distilled water as outlined in our previously posted how-to. The problem with removing the plug is it's not supposed to be reused since its NPT threaded (NPT seals by tightening until the threads are deformed- in this case against the female engine block threads). So rather than buying new plugs for future coolant changes, we developed a set of simple reusable hoses into a kit, part of which mounts in place of the plug the other part onto the lower radiator hose. This allows draining, filling, bleeding and pressure testing the cooling system without raising or going underneath the vehicle, resulting in a labor time of ~30 min In the shop we refer to this as the coolant drain line (CDL).

~1.5 gal

 

How accessible is this plug?

 

It's best accessed from underneath, with the subframe and passenger side drive shaft removed (plug easily replaced during a clutch R&R). May be possible with only the shaft removed, but this depends on one's tools and skill.

 

Just wanted to say thanks to all that contributed to this thread, you made it possible for me to fumble through my first coolant change. LOL.
Ran into a few problems along the way though... Thought i would share some challenges that may help anyone doing this in the future.
On a 2010 R57
BLEEDER VALVE: Flat head screw driver must be at least 6 inches long. That is omitting the handle part. So the steel part has to be 6 inches long to reach the screw. And the flat head point has to be relatively thin to fit the grooves of the bleeder valve.
- Continuing with the bleeder valve. Refilling coolant into the reservoir with the bleeder valve opened but the reservoir was not draining into the radiator or engine block. Close bleeder... went for a quick drive, once around the block DO NOT GO FURTHER for fear of overheating then opened the valve and it worked like a charm.
- on my model the bleeder valve screw is plastic not copper or brass Be careful not the strip it.
- Make sure you swing by Costco to get some cardboard to lay down under the car.
- I used a pair of vice grips for the hose clamp on the lower radiator.
- Drained the lower radiator with the reservoir cap and the bleeder valve opened. I only Shop vacked the lower radiator hose and got it all out. Concerned as my vacuum was 4 hp so I didn't flush it up the hose Wasn't sure if it would affect the thermostat or any moving parts up the change adversely.
- You'll want to pick up a minimum of Five 1 gallon (3.78 Litres) of deionized water. Its a pain to have to go back to the shop in the middle of it all.
- Make sure you go back and inspect for leaks or coolant level changing for the next few days.


One thing that would've helped is to be able to check the temp in the cars console.
I tried to get into the service part of the display but I couldn't change the LOCK ON to the OFF setting.

Noob mistake and avoid if possible
Try not to do the oil change where you park your car. You could have a panic attack when you smell coolant when you get in your car the next morning as spilling some on the ground doing the oil change was inevitable.

 

I want to do a coolant flush without running the car (2003 R53). I'll remove the thermostat since I'm going to replace it anyway. That will allow me to vacuum out most of the coolant even with the engine cold. If I set the heater controls with the car not running and the engine cold, will the vacuum method purge the heater core?

(Sorry to revive such an old thread but there's a lot of good information here.)