Easy way to clean out coolant passages in Block?

I posted awhile back about my 2000 Chevrolet Malibu having hesitation issues and loss of power when accelerating. Finally got around to Breaking the engine down only to find that the lower intake gasket was messed up. I need to look at the head gasket but there's coolant in some of my combustion Chambers. I don't have the resources right now to overhaul the block so what is the best way to clean the passages? It looks like there is sludge Gunk inside and i dont wanna cont
minate coolant when reassembling. Is there a solution I can use inside of the coolant passages so that It can just flow back out via drain plug?

I would not worry about the coolant passages at the moment. i would soap out a majority of the coolant out of the cylinders and clean all mating surfaces so can be reassembled. when reassembled you can then deal with a flush of the coolant system. mercedes makes a good citric flush to have done every so often on there diesels but others could be used. before you add any of this you will need to run straight water through the system and drain it multiple times till you pick up no more coolant when draining the system. you can then add the flush to water in the system to clean out any build up and let the motor run for about 30 mins. after this you are going to repeat to draining the coolant till you get clear water. I myself would rather use zerex G05 over dexcool coolant when filling the system back up.

www.ecstuning.com/b-genuine-mercedes-ben...leaner/000989102511/

1mouse3 wrote: I would not worry about the coolant passages at the moment. i would soap out a majority of the coolant out of the cylinders and clean all mating surfaces so can be reassembled. when reassembled you can then deal with a flush of the coolant system. mercedes makes a good citric flush to have done every so often on there diesels but others could be used. before you add any of this you will need to run straight water through the system and drain it multiple times till you pick up no more coolant when draining the system. you can then add the flush to water in the system to clean out any build up and let the motor run for about 30 mins. after this you are going to repeat to draining the coolant till you get clear water. I myself would rather use zerex G05 over dexcool coolant when filling the system back up.

www.ecstuning.com/b-genuine-mercedes-ben...leaner/000989102511/

Thanks for the reply. At first glance I didn't notice but I've come to realize that there's also oil mixed in those passages as well. Are you saying that it is safe for me to put dish soap in the passages and just rinse them out somehow? That was my initial thought at first but wasn't quite sure how safe it was. There's oil coolant sludge in there as well. yuck

I think 1mouse3 might have made a typo --- soak not soap. Soak up what coolant you can spray the bore with aerosol water repellant lubricant. Any coolant in the oil should collect in the botton of the oil pan and can be drained out with the oil.

To get rid of the oil in the coolant a simple water flush may be enough but if you want to do a full system clean out.
To clean out residue in the cooling systems of modern engines which contain aluminium parts you need to start by flushing out as much of the system as you can with fresh water, as a rule (where possible) flushing in the reverse direction from normal flow works best with raddiators and heater matrix. Then fill the system using a dillute organic acid solution as flushing agent. You can buy suitable citric acid or phosphoric acid on ebay or buy citric acid in packs for cleaning out deposits from washing machines and dishwashers.
After you have let it circulate through the engine for 20 minutes or so drain and flush the system with fesh water. Refil with the coolant of your choice, where I am the bigger car manufacturers OEM longlife OAT coolants are the best choice. With the correct concentration of coolant in the coolant in the system will be slightly alkaline with a PH usually between 8 and 9.