Anyone know of a good way to clean the cooling system? Its obvious that the engine didn’t get cleaned well at the machine shop. Now I have a blood red water and it contaminated the nice new aluminum radiator. COuld see the tops of the vertical tubes clogged. SO I flushed and refilled ran to temp flush and fill, flush fill flush fill. Its still pretty dirty.
Figured its worth asking for alternate ways to do this.
There are several different cleaning agents that you can buy from the parts store that will do what you want, buy the ones that are for cleaning the system as though you were going to repair a cracked block, they work best.
I tell you what works very well is vinegar. Drain the coolant, flush the system with water until it runs clear. Let it dry out overnight.
The next day fill the cooling system with pure vinegar. Let it sit overnight.
The next day drain it and flush again. You will not believe how much rust and crud comes out.
This won’t fix a rotten old radiator. Radiator fins get separated from the tubes, and the tubes get corroded on the inside from people not changing their anti freeze often enough. When a radiator gets that way it has to be replaced.
Truth. I had the same issue with my coolant - just wouldn’t flush fully clean after multiple tries. Turns out there was so much crud and rust from the fins rotting off the tubes that every time I did a new flush, more grime just mixed in. The tough part was that it looked completely fine from the top when I removed the radiator cap; it wasn’t until I pulled the whole radiator and looked from the bottom that I could tell it was shot.
Interesting! I have a crusty old engine w/a freshly re-cored radiator…I always run a special filter on the upper radiator hose, but it doesn’t separate out the super small stuff.
Vinegar cleans everything well. Even use it to clean out the trusty ole Bunn coffeemaker.
Trying the Prestone clean additive. Guess I forgot to mention the engine is a 1965 - C5AE-6015E Which was machined then forgotten in a garage. So obviously the outside looked clean but you never know the internal cleanliness. The rest of the system is all new.
The muck has to be the red oxide/rust on the internal passages of the block.
I never knew about vinegar and will most likely try that next for added cleaning.
Thank you everyone.
Have had some luck putting CLR into a radiator to remove lime scale. I pull the radiator and lay it on its back with the inlets pointing up and then fill it with a strong CLR and water solution and let it sit over night. DO NOT try this with an aluminum radiator. Then I dump the CLR and flush with a garden hose. This won’t fix solder bloom at the ends of the tubes. As Royce says if the radiator has started to separate, this is not going to work. If you have calcium and lime deposits or small rust particles that have stuck in the radiator, this can be effective. Copper and brass don’t really corrode or oxidize like aluminum or iron, but the lead and tin in solder does. If you look at the solder joints at the top of the tubes and it looks like they are blocking most of the opening into the tube, that is called solder bloom and you will to have the core rodded out. Those joints are also weakened so they may break and need to be resoldered. Finding people that have this skill is increasingly difficult. A new core may be your best choice.
I have / had the same thing ~ lots of rusty gunk coming out of the engine block after flushing / cleaning the radiator.
I’m considering taking it to a shop and having them do a cooling system “power flush” to get more of the built up crud out.