Radiator / Engine flush

dewc3

Ive read several different ways to flush the radiator and engine block on the 97 lasabre and wanted to know if the bottom radiator hose was disconnected and a water hose put into the filler hole at the top of radiator, then let the radiator fill and turn the car on and the heater, then just let the car run and drain till the water ran clear out the bottom then shut the car off, would this not flush the block also of the nasty brown water it holds? If not what is a better way

thecardoc3

Two of the front timing cover bolts goes all the way into the cooling system, they do that on purpose to help drain the block. Trying to let the engine run could cause it to overheat if an air pocket occurs. You can remove the heater hoses to give you connecting points to change the water flow direction. Most shops have tools that not only use water pressure, they also connect the shop air pressure that causes the water to pulse and vibrates and that helps loosen the debris allowing it to be removed easier. Some engines get very bad if the service is way overdue. In severe cases only full disassembly and manually removing (scraping, and hot tank agitation) removes the sediments.

imidazol97

I've read about owners removing the thermostat and putting water in there with a hose and letting it flush through the radiator, either out the lower hose or opening the drain cock on the bottom of the radiator.

Taking off the heat hoses at the tensioner also can be used to flush the heater core in both directions if you're having trouble. Those have o-rings to replace if I recall correctly.

Frankly, I'd do the thermostat and flush with engine off. Replace. Run engine to full temperature at speed to see how much gets picked up and starts moving around. Drain again. Cool. flush with hose. Fill with proper amount of coolant.

You could also try using a mild system cleaner. BUT I'd prefer to just do repeats of plain water flushing a month or so apart. Even if it means repeating buying replacement antifreeze.

If your car did not come with DexCool and did not have old style green coolant intermixed and then left to age which could leave some globs of stuff that blocked heater cores, I'd stick with the safer effort. My 98 leSabre never indicated a tendency to do either, block the heater core nor leave residue in the engine.