Solvent for cleaning manifold?

[theodore]

NaOH Sodium Hydroxide... Thats whats in oven cleaner also a bunch of other high VOC chemicals, I got it at Home Depot, Heavy Duty industrial degreaser (purple stuff). Water based so mix 50/50 with Hot water and keep it hot if you can. Soak overnight then get out the brushes after breakfast.

 

[Mako]

Burning works well but aluminium can be damaged and significantly weakened if overheated so be careful. I soak for a day in glycerol (biodiesel byproduct) and it washes out clean.

 

[r3dplanet]

I use Berryman's Chem-Dip, specifically the big 5-gallon bucket. Horrible stuff. But you can just drop in the manifold, EGR valve, etc, and let it sit for a day or two and then it's straightforward to remove with a wire brush. Easy-peasy. Your mileage may vary, but it's always worked for me.

 

[Mike_04GolfTDI]

I haven't tried it on an intake, but I suspect furniture stripper would work. It'll remove paint in seconds, which soaking in Varsol or diesel fuel wouldn't touch. It dissolves protective gloves, even epoxy!

It's terrible, nasty, dangerous stuff. Just what you need to clean sludge out of an intake.

Be careful if you try it. Follow all warnings on the label. If it contains Methylene Chloride it can kill you if used improperly (but is available off the shelf in hardware stores).