coolant changing issues

I want to change my coolant. I checked it and the dipstick there has about 1/8 inch of brown sludge on it. Should this be something I should be concearned with? Should I flush the system.

Also, it changing the coolant as easy as draining it out of the bottom drain valve and re-filling it through the top, or am I missing something here. Thank you for your help.

thats what I did was drain it and refill it and then check it cold and then hot, and check it several more times after that...:)

i would also remove the resorvoir (which is located under the battery) and flush it also. good luck.

I'm not sure how to actually flush the radiator. But I had some sludge too and just changed the fluid and it went away. When putting the fluid back in, make sure you have the coolant lines up in the air to bleed the system. Make sure coolant comes out of both while reconnecting them to make sure all of the air is out. Check coolant level frequently after re-filling as air will escape and the level will drop.

I had that brown sludge all over my dipstick too, leading me to believe that DexCool is NOT good for 150K.

I went to a great radiator shop with a powerflushing system. They flushed my system out real good and filled it up with DexCool for $65 (I brought my own DexCool).

I would not recommend doing it yourself because some LS1 cooling systems have bleeders, and they can be tough to get to. Just to be on the safe side I'd find a radiator shop in your area with a powerflushing system and take it there.

Simple flush:

dump old fluid out. Put draincock back in; tighten down. fill system with water. Start motor. Keep water hose handy and running slowly. remove radiator cap after motor warms. remove draincock. run water thru system while motor running. About 5-10 mins is plenty. Turn off motor. Let all the water run out of system. Secure draincock again. Refill system with DexCool/distilled water mix (max 70/30; min. 50/50)

Flush with additive:

dump old fluid out. Put draincock back in; tighten down. fill system with water and radiator flush product (Ex: Prestone radiator flush... but be careful to make sure it's GM approved). Follow instructions on flush product package. Drain and refill with DexCool mix of 70/30 to 50/50).

This is how I've done it both ways for the last 25 years and seems to work for me.

Daryl

PS- but if $ permits, go for the powerflush by a professional. Just my $.02 worth.

Thanks for your help. I'm gonna try it myself and check in a week to see if a flush is needed.