I have previously, factory intake manifold, been able to stabilize the idle mixture on my 300ci six in my pickup by placing a cover plate closing the bottom of the heat riser pocket and plumbing engine coolant through holes in the plate into the pocket. The engine is equipped with headers so I don’t have normal heat riser available. Is there a specific anti-freeze to be compatible with the manifold aluminum?
Although the 6019-DP was designed to be used with the factory exhaust manifold and use it as a source of heat for the intake manifold, a 601-9DP can use engine coolant for heat (but it may not be a simple bolt on addition). Manifolds made since 2015 have used a different core box for the exhaust heat area. The different core box makes it less likely that water can enter the intake manifold area. Earlier manifolds, using older core box, may have some porosity issues which would allow water to enter the intake manifold runners. The best way to determine whether your intake can use engine coolant as a heat source is to invert the intake and place water in the exhaust heat chamber and let it sit for awhile. If no water enters the intake runners, you can use engine coolant for heat. If water enters the runner area you cannot use that manifold with coolant for heat.