Lou C
Supreme Mariner
- Joined
- Nov 10, 2002
- Messages
- 13,064
well here is the thing, these are open cooling systems that are not pressurized. As such, in order for them to keep the engine cool, there has to be a flow of a high volume of water in and a high volume of water out to carry away the heat. Either you're not getting enough in, enough out or there are deposits in the cooling passages of the engine that are interfering with heat transfer. Assuming that you do not have blown or leaking head gaskets. We had this on a '98 Subaru, 2x. When the head gaskets on these blow, the exhaust gas pressurizes the cooling system and it causes overheating at anything above low speeds. They did not get antifreeze in the cyls, or out the exhaust. The exhaust gas would push antifreeze out of the radiator and overflow the overflow tank. A dead give away was bubbles in the overflow tank and a black carbony like deposit showing up in the overflow. It did this both times the HGs failed.