AMD[H]unter
Registered User
We just finished working on my buddy's 93 SC, and he is having a problem with something. This has happened before and after we took the top half of the motor apart. When under boost, water is pushed into the overflow reservoir, and it will not suck it back into the cooling system. At first, we thought it might be a seeping HG, so we wrote it off for a couple weeks because we were doing the rebuild then. The car has a new radiator, different heads, MLS HG's, head studs, and lower intake. The heads were checked for warpage, and they were fine. What could be the issue here? If more info is needed, let me know.