Sometimes things are better when left alone.

[Rick_Grff]

I noticed the radiator water in my 99 Tahoe was looking dirty. So I drain it take out the thermostat and put therm cover back on. Hook my hose to the hot water and began flushing. Until the water ran clear. Put everything back together and filled it up. It was getting dark so I quit working on it. Next morning theres a puddle sure enough the radiator got a hole in it. I presume its from flushing all the rust out.

 

[Fless]

Better to have it happen at home as opposed to out on the road.

 

[Doubeleive]

gm seems to think it is ok to run coolant to 100k. it's not, not by a long shot. I always recommend flushing the coolant annually.

 

[OR VietVet]

Yep, "looked dirty", meaning what color. If brown looking, you let go far too long before addressing the cooling system. I did notice that after the flush, you were gonna "put everything back together". Replace the thermostat when you do the radiator. Also, check the water pump weep hole for a stain. That may be close behind for failure. Hoses may be close too because they wear from the inside out. In other words, that dirty coolant eats from the inside out and the entire system is suspect.

 

[YukonGTmaster]

I'm on my 3rd Radiator on my '97 GT. They all failed where the plastic end caps are swaged to the radiator core.

 

[Eman85]

Your radiator failed because it's old and plastic.