how basic is the procedure/ any one know of any post or tutorial that can show me how to do it? I wanna make sure i do things right.

http://www.bonnevilleclub.com/forum/...=article&k=100

Go to walrmar and get a FlushnFill kit for about $4.00, 2 gals Prestone mix with all (not pre mixed) and maybe some Superflush or Super radiator cleaner

Follow the directions on the FlushnFill kit. The air purge vavle is on top of the thermostat housing for when you are at the 'bleed the air out' step.

All in all, its pretty simple.

I have have 3800 L27, Same prodcedure apply?

I would follow the same procedure for the L27. It may not be as prone to trap air in the intake manifold as the L36, but filling at the thermostat opening as described in the Techinfo article (linked for you above by twobonnies) is still a good idea.

If you have the time, and energy, and have a nice warm place to work with a sanitary drain nearby, you might want to try this method for flushing. http://www.bonnevilleclub.com/forum/...ic.php?t=84203
Following that method, you will perform a true reverse flush for the radiator, engine, and heater core. Using the flushing Tee alone will not provide a reverse flush for the heater core or for the entire radiator, just the side tank on the passenger side.

Reversing the direction of normal flow through the system is more effective in flushing sediment from narrowed and blocked passages in the system than flushing in the normal direction of flow. Normal flow is from the bottom of the radiator to the water pump, from the water pump to the engine block both sides, up into the cylinder heads and intake manifold, out of the intake manifold passenger side through the coolant elbow, to the heater core through the top heater hose, back from the heater core through the lower heater hose to the water pump, out of the intake manifold driver'* side to the radiator top hose through the thermostat (only when open) across the radiator from the driver'* side to the passenger side, out the bottom of the passenger side tank.

Does this link still work? http://www.bonnevilleclub.com/forum/...=article&k=100
Want to make sure I do this raditor collant flush correctly and get all the air out of the lines especially after the thermostat.

This thread is old and some of the links are part of the old system that has not been recovered...that'* why they no longer work.

No need to use a chemical flush unless you have visible corrosion and rust in the radiator. Just drain and capture the old fluid for recycling. The valve on top of the t-stat housing is used to bleed the system. You'll need to open and close that a couple of times to get all the air out.

I know this is an old thread, but today I am dropping the necessary coin to 'repair' my manifold (upper and lower). As far as flushing coolant, I read that GM uses Dexcool, and cannot be mixed with other coolant brands, and you cannot entirely flush the system to rid it of Dexcool. Also of note is that Dexcool was known for dissolving the manifold gasket. I had to ensure that I was getting the retooled GM gasket to avoid the same issue down the road.

Make sure your engine is cold lol, unscrew the lower part of the radiator hose to get rid of all the coolant, then close up hose and add water to the radiator, let the motor run for like 10min then release hose again and fill up radiator with half Dex-cool and water and your set. Change the thermostat while your at it. Remember let the motor run with the radiator cap off until it starts bubbling, your most likely gonna have to top it off few times.

dex cool??? hell naw... dats the **** that melts your intake gaskets.. i'd definitely go with prestone or any other antifreeze/coolant mix other than dex cool