With all the discussion on changing thermostats and OAT, Dexcool, standard green coolant and WaterWetter I wish we had a writeup for the correct method for a complete flush and coolant swap out. I see a lot of conflicting recommendations also, for instance:

Open 2 drain plugs
There are no drain plugs
Flush with tap water
Only flush with distilled water (seems like you need a lot of that)
OAT or Dexcool will ruin your engine
OAT or Dexcool will save your engine
Ensure you get all OAT out or your car will turn into a flesh eating gremlin



Here is my situation: I need to R&R my throttle heater plate and gasket and swap the thermostat for the 180 D model. And I figure based on the recent knowledge base here I will switch the coolant to the 50/50 standard green coolant. My short block was replaced 30K ago and my radiator and connected major hoses were new about 20K miles ago.

If I understand the RAVE manual I need to:
1. Remove exp. tank cap
2. Loosen radiator bottom hose and drain fluid into a pan
3. Remove left and right hand block plugs
4. Flush with water (distilled or out of a hose???) via the T hose fitting
5. At this point I will R&R T.H. plate and swap thermostat and reattach hoses and install block plugs.
6. Release top hose from radiator cowl lugs and rest on lugs
7. Remove bleed screw from T hose connection
8. Remove coolant exp. tank from bracket and raise and fill with about 4 Lt coolant
9. Keep filling until coolant runs out of bleed hole
10. Install bleed screw and continue to fill until fluid reaches base of filler neck
11. Install exp. tank cap and refit tank to bracket
12. Start engine and check for leaks, heat to operating temp and shut off.
13. Check for leaks and top up exp. tank when cool enough to open
14. Dispose of used coolant correctly or EPA will knock on your door
15. Sit down and have a cold beer! or 2 or 3!

Followup questions:

1. Should I attempt to back flush the radiator just to ensure I got as much debris as possible out?
2. What about flushing the heater core? I'm thinking I will swap out those hoses as they are originals with 120K miles on them although here in the south I don't use heat a lot but I want to ensure I get all the OAT out.

 

- I read that the block drains are a huge pain as they are a square bolt and usually corroded in. When I flushed out my block sealer treatment, I taped a leaf blower to the upper coolant hose and blew everything out of the water pump.

- I think Buzz posted an Official Dexcool Eradication Procedure on the forum. Search should come up with it.

 

I am sure that my method is not based on any extensive knowledge, but rather what made the most sense to me. I do the garden hose as well as possible and both directions, then rinse out the tap with distilled, then put back together, start the fill bleed procedure

 

Funny how much the LR designers loved those square headed plugs, they must have been plumbers in their former lives.

 

The block drains, in my experience, aren't that bad provided you use an 8pt socket.
I never flush with distilled water. I just use the garden hose and back flush it, including the heater core. If I need to I install a 'T', that will accept a garden hose, in one of the heater hoses.
Once that's all done if I'm feeling OCD that day I'll fill it with just distilled water and run it up to temp to fully disperse any residual tap water minerals, then drain and fill with coolant (50/50 homemade with Peak Long Life full strength/distilled water). The Peak is on sale this month at Advance Auto for $9.99 a gallon.

If you're going to all that trouble it would probably be a good idea to flush the radiator too.

 

This is great!! I have got to try this next time Duct tape handy mans secret weapon.
Block drains are a pain if you don't have a lift. I used a garden hose and probably killed every stray animal near here. Also there is no graceful way to drain the system. It just goes everywhere.
My 2 cents.