Posted by Greg Coffin [172.68.1.162] on Sunday, August 17, 2025 at 09:01:31 :
In Reply to: Goo in Radiator posted by Torvald [162.158.42.134] on Saturday, August 16, 2025 at 17:02:48 :
What color is it? If it's orange it's rust, probably from the engine block. The block may not have been cleaned well enough when it was rebuilt. I've seen a similar goo on cooling systems, and on irrigation pumps with high iron content in the water.
You can drain the coolant and run a batch of Evapo-Rust in the engine for a few weeks. That will clean it out very well. I buy it in 5 gallon buckets from Summit Racing. It's much cheaper that way, and they will ship for free if you reach a minimum dollar amount. A huge savings on 40lbs of material
Follow Ups: