Flushing Radiator

I'd flush it - don't think you are going to cause problems by flushing it

Flush and Refill it and be done with it.

What I would do is drain the radiator from the petcock, then pull the lower hose and the thermo housing, and get a garden hose and flush it though the intake and out the lower hose.. This will get most out... You might also want to run some Flush Chemical through it to break all the crap up first. This will insure all of the rust and corrosion will come out of the motor... Do the same with the radiator... Except put the garden hose in the upper hose and let it come out the bottom... You'll be surprised at the crap that comes out... If you have that many miles and never a coolant flush, your coolant should be nothing but rust.... Nasty.

Nick

yep, i would also flush away. i would likely not use any chemicals unless you are prepared to buy new radiator, etc if it leaks (i feel there is less chance of a leak with not using any special products).

i would simply flush well and put it together. then flush again in the not so distant future.

oh yeah, i would toss a new stat and cap on there (as i bet you are planning). i bet your coolant reservoir bottom is nasty.

my two cents. good luck.

How bad is the coolant? If there is a lot of sediments (muddy buildup) then you need to use caution. If there is a lot of sediments, you need to get them out in one pass.

First, drain the radiator. You may want to bypass the heater core because sediments will clog a heater core because they have real small fins and are a PITA to replace. Use the hose and run water throught the lines both ways, this will flush out without the danger of radiator junk clogging it. Then remove the t-stat (this makes it easier, won't have to wait until it heats up) and put the housing back, don't worry if it leaks some on the old gasket, your going to replace anyways when you install the new t-stat. Pull the upper hose. Fill the radiator with water and leave the hose in the radiator while running with the upper hose removed. Start the car and all the water will flush the gunk out. This way no fluid will recycle. When all junk is out, re-attach the upper hose. Add some radiator flush and allow it to run normally, maby take if for a drive. Pull th upper hose, add garden hose again and flush again. Do this until the water comming out looks like the water going in. Drain radiator, install new t-stat, re-attach the heater core, and then fill with coolant.

ehh i say just flush it so you know its been done.